New Zealand HMS Fisheries

Transcription

1 New Zealand HMS Fisheries Medium Term Research Plan /09 to 2009/10 August 2008 Prepared by the Ministry of Fisheries Science Group, the HMS Fisheries Managers & the HMS Fisheries Research Planning Group

2 TABLE OF CONTENTS INTRODUCTION HMS PROJECT LIST GENERIC RESEARCH ISSUES TUNA BILLFISH PELAGIC FISH TAKEN AS BYCATCH GAMEFISH TAG RECAPTURE PROGRAMME PELAGIC SHARKS OBSERVER COVERAGE HMS Medium Term Research Plan

3 INTRODUCTION The goal of the Ministry of Fisheries is to maximise the value New Zealanders obtain through the sustainable use of fisheries resources and protection of the aquatic environment. The Fisheries Act 1996 (the Act) provides the legislative framework to achieve this goal, with the purpose of providing for the utilisation of fisheries resources while ensuring sustainability. The main management measure provided for in the Act is the total allowable catch (TAC), which is set by the Minister. The Minister is required to set a TAC that maintains a stock at, or above a level that can produce the maximum sustainable yield (MSY). In determining the rate at which a stock is moved towards MSY, the Minister must consider relevant scientific, economic, social and cultural factors. A significant part of New Zealand s HMS fisheries are based on highly migratory stocks whose range extends beyond New Zealand fisheries waters. For these stocks it is not currently possible to estimate MSY specifically for the part of the fishery found in New Zealand waters and other management measures are required that meet the purpose of the Act and New Zealand s international obligations. In this context information is required to contribute to the assessment and objective setting for management of international stocks. Ultimately the actions of the Minister will be underpinned by the availability of high quality scientific, economic, social and cultural information; however, for New Zealand s HMS fisheries there is generally a paucity of information in each of these categories. Notwithstanding the need for information covering the range of research disciplines above, information on the status of HMS stocks and the effects of fishing is arguably the most essential at this stage; and to this end, there is a need to focus research efforts on obtaining basic biological information (e.g. growth and natural mortality), catch information, non-target catch information and time series of abundance indices for most species so biomass and sustainable yield can be estimated and effects assessed. Although biological research currently dominates this medium-term research plan, in time, research on economic, social, cultural and ecological aspects of the fisheries will be required. Research Planning Process The Ministry of Fisheries has a planning process to establish the future directions and priorities for fisheries research in conjunction with fisheries stakeholders. The Ministry has set a longer term direction of determining research priorities in the context of fisheries plans developed for fish stocks and/or fish stock complexes. Until this approach is fully implemented the Ministry will continue its existing research planning process as follows. The Ministry convenes a Research Co-ordinating Committee (RCC) annually. Its membership consists of Approved Parties for consultation on the nature and extent of required fisheries research services, and Ministry staff. The main purpose of the RCC is to serve as a consultative forum with fisheries stakeholders to discuss, evaluate, and make recommendations on the future directions for fisheries research. These recommendations come from Research Planning Groups (RPGs) that contribute to the process in specific research areas (e.g. the HMS Fisheries Research Planning Group HMSRPG). The Ministry also convenes the research planning groups with membership composed of Ministry Science and Fisheries Management staff, representatives of stakeholder organisations and science providers. HMS Medium Term Research Plan

4 Both the RCC and RPGs are involved in the development of the following plans for fisheries research: the Ministry of Fisheries Strategic Research Directions document: containing strategic context, strategic directions, goals, strategies and strategic objectives for research for the next five to ten years; the Medium Term Research Plans: containing research plans for a species or fishery or topic over three to five years. These plans will be consistent with the Strategic Research Directions document; and the annual Fisheries Research Services Plan/Statement of Intent: containing details on each research project to be undertaken in the next fishing year. These are used as the basis of consultation on the nature and extent of required fisheries research services. These plans will be consistent with the Strategic Research Directions document and the relevant Medium Term Research Plan. The Ministry of Fisheries research planning process involves consultation, planning and project development. This process is informed by the results of previous research through the stock assessment working group process (e.g. for HMS fisheries the HMS Fisheries Stock Assessment Working Group HMSWG). Development of the Ministry of Fisheries Strategic Research Directions Document and its Research Goals, Strategies and Strategic Objectives The Environment 2010 Strategy states the goal for sustainable fisheries is to conserve and manage New Zealand s fisheries for the benefit of all New Zealanders by providing for sustainable utilisation of fisheries resources, including commercial, recreational and Mäori customary take. In the Act ensuring sustainability means maintaining the potential of fisheries resources to meet the reasonably foreseeable needs of future generations; and avoiding, remedying, or mitigating any adverse effects of fishing on the aquatic environment. The Act also defines utilisation as conserving, using, enhancing, and developing fisheries resources to enable people to provide for their social, economic, and cultural well-being. In addition, the Fisheries Act 1996 requires that, in relation to the utilisation of fisheries resources or ensuring sustainability, the following environmental principles shall be taken into account: (a) associated or dependent species should be maintained above a level that ensures their long-term viability; (b) biological diversity of the aquatic environment should be maintained; and (c) habitat of particular significance for fisheries management should be protected. The types of research required by the Minister of Fisheries to achieve the goal of sustainable utilisation fall into nine key research areas, namely: Fisheries Resources; Harvest Levels; Aquaculture & Enhancement; Aquatic Environment; Disease & Exotic Organisms; Cultural, Economic and Social Factors; Customary Maori; Marine Biodiversity; and, Marine Biosecurity. The research goals, strategies and strategic objectives for each key area are detailed in the Strategic Research Directions document. HMS Medium Term Research Plan

5 Scope of the Medium Term Research Plan for HMS Fisheries Research New Zealand s HMS fisheries resources include the highly migratory species (tunas, billfish, pelagic sharks and associated non-target fish species) found throughout New Zealand fisheries waters at different times of year, have been exploited at various rates, are usually assessed through international fora, and the distribution and abundance of these species within New Zealand fisheries waters is generally poorly understood; and This plan also contains information and research planning for generic research programmes of direct relevance to HMS fisheries: the gamefish tag programme that relates specifically to a variety of HMS species (striped marlin, mako shark and yellowfin tuna); and the observer programme and its data collection for all HMS fisheries. Intent of the Medium Term Research Plan for HMS Fisheries Research This medium term research plan for HMS fisheries research has been developed using the goals, strategies and strategic objectives contained in the Strategic Research Directions document, and in the context that maintaining stocks at or above the stock biomass capable of producing the maximum sustainable yield for most domestic fish stocks is a requirement in the Act. For highly migratory stocks where the maximum sustainable yield cannot be estimated, alternative management measures are also required to be consistent with the purpose of the Act. It is recommended that you also consult the Report from the Fishery Assessment Plenary, May 2006: stock assessments and yield estimates, which contains a complete account of the stock assessment information. This medium term research plan for HMS fisheries research is a working document that the Ministry of Fisheries intends updating annually. The update will occur through internal Ministry of Fisheries analysis, and through input from interested parties in the research planning consultation process (comments can be forwarded at any time to Stephen.brouwer@fish.govt.nz). This medium term research plan for HMS fisheries research is intended to: indicate the current research approach being taken for individual HMS fisheries with respect to sustainability and ecosystem issues, and identify the research and monitoring that is required to meet information needs; assist in determining priorities for research in the next year; and provide a clear indication to stakeholders and research providers on the medium term research directions being proposed by the Ministry of Fisheries for HMS fisheries. HMS Medium Term Research Plan

6 Layout of the Medium Term Research Plan for HMS Fisheries Research This plan presents a summary for all the currently exploited HMS fisheries resources at a species level, or where appropriate sets of similar species. For each species, or species group, the following information is given: a summary of the fisheries for the species, or species group, including commercial and noncommercial fisheries; a summary of our current knowledge of the status of the stock, or stocks; a summary of the stock assessment approaches for the species or species group; a chronology of research undertaken by the Ministry of Fisheries to date (and other research where appropriate); an analysis of the above information and the research implications; all resulting in a medium term research plan for research for the species or species group including recommendations on priority and observer coverage. Note Details of a series of generic projects that span several HMS species are given only once (the first time they appear in a chronology of research table). After that they are cross-referenced. Those projects by research year are: ENV9702, PEL9701, REC9701 ENV9802, REC9803, TUN9801 ENV1999/03, TUN1999/01 PEL2000/01, MOF2000/03G PEL2001/01, TUN2001/01 PEL2002/01 PEL2003/01, PEL2003/02, TUN2003/01 REC2004/01, REC2004/02, TUN2004/01, OBS2004/05 PEL2005/01, TUN2005/02, OBS2005/05 PEL2006/01, PEL2006/02, TUN2006/02, and OBS2006/06. PEL2007/03, OBS2007/05 HMS Medium Term Research Plan

7 HMS Project list (23 rd September 2008) 1. Management of data from the gamefish tag recapture programme. 2. Multi-year stock monitoring of striped marlin including logbook programme implementation. 3. Albacore maturity data collection. 4. Stock monitoring of albacore. 5. Catch-at-age of Southern bluefin tuna. 6. Characterisation of New Zealand tuna fisheries for international obligations including sharks and full gear and observer. 7. Commercial catch sampling programme for highly migratory species. 8. Blue shark conversion factors???? GENERIC RESEARCH ISSUES This section briefly highlights issues that are of relevance to all HMS fisheries and will need to be addressed in future research planning. These issues have been raised by the research planning process and many are also issues for other fisheries research planning groups. Obtaining Efficiencies in Catch Sampling Programmes programmes in fish sheds or at sea occur for many species throughout New Zealand. Some programmes are single-year/single-area projects, whilst most are multi-species and occur over several years. There are efficiencies that can be gained by combining shed sampling programmes where sampling occurs in the same sheds during the same period for different species. Investigation of how best to obtain such efficiencies needs to occur. This is an issue across HMS species and also species dealt with in the Inshore Research Planning Group. Multi-year Research Programmes Where a research programme is generally rolled over from year to year, efficiencies can be obtained by tendering for a multi-year project. However, in an uncertain medium term planning environment (e.g. the development of fisheries plans) these potential efficiencies may be sacrificed to allow future flexibility. In order to purchase research services more efficiently, effectively and economically in future, exploration of the potential for partnerships with selected research providers is required. Regional Stock Assessment and Biology Projects For tuna, pelagic sharks, billfish, and other highly migratory species encountered in fisheries within New Zealand fisheries waters, the stocks are usually found over a wide area (e.g. South Pacific Ocean). Furthermore the stocks are generally assessed (if at all), by Regional Fisheries Management Organisations (e.g. the Commission for the Conservation of Southern Bluefin Tuna [CCSBT]) or through collaborative efforts among individual countries. Research into these species must be sufficient to allow for local monitoring of the subcomponents of these stocks to meet domestic fisheries management requirements, but also provide a contribution to the wider understanding and sustainability of these species at the level of the greater stock. In the future such work could be in the form of collaborative research projects among interested countries. It may be necessary to establish an alternative mechanism for funding New Zealand participation in regional collaborative projects. HMS Medium Term Research Plan

8 Research to Address the Ecosystem Approach to Understanding Fisheries Exploration of ecosystem level effects of fishing is generally not feasible at the scale of an individual fishery within a specific management area. Accordingly generic studies are required to address ecosystem scales. Generic programmes are generally of benefit to all fishers harvesting with a particular method or within a specific ecosystem. However, to address ecosystem scale issues in one research project is also generally not feasible. Rather, a start needs to be made with smaller projects to explore specific issues that will collectively broaden our understanding of the entire system. Cumulative efforts over several projects and years will need to be reviewed to provide the information basis for an ecosystem approach to understanding fisheries. Broader ecosystem issues, especially in relation to any predator/prey relationships have not yet been considered for New Zealand s HMS fisheries. In terms of the Fisheries Act, the interdependence of stocks may be an important determinant in setting a catch limit that maintains a stock above the level which will produce MSY for prey species to allow for predation and ecosystem functioning. Pelagic prey species include pilchards, anchovies, jack mackerels, blue mackerel, kahawai and trevally. There are also a variety of issues relating to the removal of apex predators such as billfish, tuna and kingfish from pelagic ecosystems (such as prey fitness) that are poorly understood. Co-ordination with the Aquatic Environment Research Planning Group is required to ensure an effective research programme on the effects of fishing for HMS fisheries at an ecosystem scale. Biomass Estimates for HMS Species Fishery independent estimates of biomass are not available for many of the small- and medium-sized pelagic species found in New Zealand. The suite of methods available for fisheries independent estimates have been reviewed and were generally found not to be cost effective in the New Zealand context. However, as these methods develop and our knowledge of fish stocks improve we will need to review whether fisheries independent indices of abundance can be reasonably obtained. Recreational Harvest Estimates For some HMS fisheries, one of the fundamental problems in assessing stock status and the effectiveness of management measures is the lack of robust estimates of recreational harvest. Research to address this issue is undertaken through the recreational working group, but is of fundamental interest to the HMS fisheries research planning process. Data describing recreational catch/effort time series may also be important for some species in a regional stock assessment context. Customary Harvest Estimates For some HMS fisheries, one of the problems in assessing stock status and the effectiveness of management measures may be the lack of robust estimates of customary harvest. Research to address this issue is undertaken through the customary fisheries research planning group, but is of fundamental interest to the HMS fisheries research planning process. Data describing customary catch/effort time series, and especially substantial changes in the quantity of this take, are therefore of considerable interest to the HMS fisheries working group. Improving Catch/Effort Data Collection For several HMS fisheries, commercial catch/effort data are still collected on basic forms with only gross spatial resolution and limited or no information on catch of non-target fish species. To improve information available for assessments in future, there is a need to review the data collection forms for these fisheries and update catch/effort forms as appropriate. This work will occur via the Ministry of Fisheries Research Data Management group in accordance with the Catch Effort Strategic Information Plan. The forms for tuna longline fisheries have recently been reviewed. In HMS HMS Medium Term Research Plan

9 fisheries, forms for purse seine fisheries and troll fisheries have been identified as of most immediate urgency for future review. Utilising international research opportunities Several of the HMS species found in New Zealand fisheries waters occur in other countries waters and on the high seas (e.g. yellowfin tuna). As a result several other countries and international organisations undertake research into the biology, ecology and abundance of HMS fish stocks. This research may be or direct relevance to New Zealand (e.g. a stock assessment of South Pacific albacore by the Scientific Committee o the WCPFC) or of indirect relevance (e.g. the development of a new method of estimating HMS fish stock abundance by aerial sightings in the North Atlantic). Tracking new developments of relevance to New Zealand s HMS fisheries are therefore crucial in avoiding research duplication and ensuring maximum value is obtained from sharing information. In some cases, it may be in New Zealand s best interests to co-operatively undertake research with other countries to achieve objectives that we can not achieve independently or to reduce costs. Postgraduate research opportunities From time to time the HMSWG and HMSRPG identify research questions that for various reasons are not suitable for funding through the annual research planning process (generally these are questions that would be nice to know but are not considered as a high enough priority for the fishery). In some cases these questions are tangible in a one-two year period, of benefit to fishers and fisheries management and relatively low cost. Such questions may make ideal post-graduate projects for university students. The HMSWG and HMSRPG intend to keep a record of such questions and would like to work with universities to see some of these questions answered. HMS Medium Term Research Plan

10 TUNA Albacore tuna (Thunnus alalunga), bigeye tuna (Thunnus obesus), Pacific bluefin tuna (Thunnus orientalis), skipjack tuna (Katsuwonus pelamis), southern bluefin tuna (Thunnus maccoyii) & yellowfin tuna (Thunnus albacares) The Fisheries Bigeye (Thunnus obesus), Pacific bluefin (T. orientalis), southern bluefin (T. maccoyii), and yellowfin tuna (T. albacares) were introduced into the QMS on 1 October 2004, each under single fishstocks BIG 1, TOR 1, STN 1, and YFN 1. These tuna were added to the Third Schedule of the 1996 Fisheries Act with a TAC set under s14 because they are highly migratory species and it is not possible to estimate MSY for the part of the stock that is found within New Zealand fisheries waters. Southern bluefin were also added to the Sixth Schedule of the 1996 Fisheries Act with the provision that a commercial fisher may return any southern bluefin tuna to the waters from which it was taken from if it is likely to survive on return and the return takes place as soon as practicable after the southern bluefin tuna is taken. With the exception of southern bluefin, management of all tuna stocks (those above plus skipjack and albacore tuna) throughout the western and central Pacific Ocean (WCPO) will be the responsibility of the Western and Central Pacific Fisheries Commission (WCPFC). Under this regional convention New Zealand will be responsible for ensuring that the management measures applied within New Zealand fisheries waters are compatible with those of the Commission. To date, this Commission has passed binding measures in relation to yellowfin, bigeye, and south Pacific albacore tunas ( Management of southern bluefin tuna throughout its range is the responsibility of the Commission for Conservation of Southern Bluefin Tuna (CCSBT) of which New Zealand is a founding member. Current members of the CCSBT also include Australia, Japan, the Republic of Korea, and the Fishing Entity of Taiwan. The Republics of South Africa and Indonesia have expressed interest in becoming members of the Commission. Determination of the global TAC and provision of a national allocation to New Zealand is done by the CCSBT. New Zealand was allocated a catch limit of 420 t (whole weight) at the 11 th meeting of CCSBT in October This allocation has been at the same level since HMS Medium Term Research Plan

11 Commercial The species captured in this multi-species fishery are albacore (Thunnus alalunga), bigeye, pacific bluefin, skipjack (Katsuwonus pelamis), southern bluefin, and yellowfin tunas. Recent catches (based on Monthly Harvest Returns or Licensed Fish Receiver Returns) by fishing year within New Zealand fisheries waters for all tunas (t) and the TACs (t) and TACCs (t) for bigeye, Pacific bluefin, southern bluefin and yellowfin tuna are: Albacore BIG 1 Skipjack STN 1 TOR 1 YFN 1 FMAs All All All All All All TACs TACCs / yr range In addition to the catches within New Zealand fisheries waters, some fishing occurs in the high seas and in the zones of other nations. New Zealand has four large-scale purse-seine vessels that fish on the both inside and outside the New Zealand EEZ. In the past five years these vessels have taken annually between 10,000 and 15,000 t of skipjack tuna and 2,500 to 4,000 t of yellowfin and bigeye tuna outside the New Zealand EEZ. Albacore Albacore caught in New Zealand fisheries waters are part of a single South Pacific Ocean stock that ranges from the equator to about 45ºS. Recent annual catches from the south Pacific stock have ranged between 25,000 and 40,000 t; about 75 % of which is caught by longline vessels with the rest taken mainly by trolling. The New Zealand fishery is predominantly a summer fishery in which over 95% of landings occur before May. Trolling is the main method used by domestic fishers (77.4 % of all reported catches) followed by longlining (21.1%). Bigeye Bigeye caught in New Zealand fisheries waters may be part of a single Pacific Ocean stock ranging from about 40 N to 40 S across the entire Pacific Ocean basin, but are assessed and managed based on two assumed stocks, east and west of 150ºW. In New Zealand bigeye is caught throughout the year but mainly from November to May (about 75 % of landings occur during this time). Domestic longliners account for over 99 % of all reported bigeye catches within New Zealand fisheries waters. Pacific bluefin Pacific bluefin caught in New Zealand fisheries waters are probably part of a single Pacific Ocean stock ranging from about 40 N to 40 S across the north and southwest Pacific Ocean. Recent electronic tagging has indicated that fish that are found off the WCSI in August / September remain in NZ waters until at least February. Skipjack Skipjack caught in New Zealand waters may be part of a single Pacific-wide stock that ranges between 40 N and 40 S, but are assessed and managed based on two assumed stocks, east and west of 150ºW. In New Zealand, fishing for skipjack occurs is in the Bay of Plenty and along the east and west coasts of the northern part of the North Island. Southern bluefin Southern bluefin tuna are part of a single stock found in the Atlantic, Indian and western Pacific Oceans, primarily from S. Only a small amount of the global southern bluefin catch is taken in New Zealand waters, with most occurring in high seas areas of the western HMS Medium Term Research Plan

12 Indian Ocean, off South Australia and off Tasmania. Southern bluefin tuna are caught in New Zealand waters all year round but the main fishing season is from June to August. Longlining is the main method currently used by domestic fishers. Yellowfin Yellowfin may be part of a single Pacific-wide stock that ranges between 40 N and 40 S, but are assessed and managed based on two assumed stocks, east and west of 150ºW. Yellowfin catches in the Pacific have almost doubled since the 1980s to be about 380,000 t. In New Zealand waters, yellowfin is taken all year round but it is predominantly a summer fishery (January to April). There is little targeting of yellowfin, it is mainly a bycatch species of the bigeye longline and albacore troll fisheries. Recreational Allowances for recreational catch have been set for the introduction of some tunas into the QMS from 1 October The total recreational allowance was set at 8 t for BIG 1, 1 t for TOR 1, 4 t for STN 1, and 60 t for YFN 1. A recreational allowance for albacore and skipjack tuna has not been set to date. Tunas, in particular yellowfin tuna and more recently Pacific bluefin tuna are prized gamefish often targeted by recreational anglers. The two smaller tunas, skipjack and albacore are the species most commonly encountered by recreational anglers, with skipjack predominantly used as bait. Bigeye tuna is less commonly encountered by recreational fishers. No recreational harvest estimates are available for tunas, as they were not included in the national marine recreational fishing surveys, but it may be possible to obtain estimates of those fish landed through gamefishing clubs, which are thought to make up the majority of the recreational catch of the larger tunas (e.g. yellowfin, bigeye, and the two bluefin species). New Zealand recreational catches will be extremely low in terms of overall stock removals. Customary non-commercial An allowance for customary catch has been set for the introduction of some tunas into the QMS from 1 October The total customary allowance was set at 4t for BIG, 0.5t for TOR, 1t for STN, and 30t for YFN. A customary allowance for albacore and skipjack tuna has not been set to date. There is no information available to allow estimation of the amounts of tuna taken in the traditional Mäori fishery, but catches are assumed small in the context of the overall removals. Stock Status Albacore Albacore are assessed as a South Pacific stock. The 3rd meeting of the WCPFC Scientific Committee (SC) provided the following summary on the status of south Pacific albacore: A full stock assessment was not undertaken for south Pacific albacore in 2006, but the 2005 assessment was updated using new data for 2004 and The key conclusions were similar to those of the 2003 and 2005 assessments, i.e. that overfishing is not occurring (Fcurrent / FMSY <1) and the stock is not in an over-fished state (Bcurrent / BMSY >1). Overall, fishery impacts on the total biomass are low (10%), although considerably higher impacts occur for the portion of the population vulnerable to longline. The model estimates that recent recruitment is below average and, consequently, the portion of the population vulnerable to longline is predicted to decline further in the next 2-3 years. The assessment conclusions were relatively insensitive to a range of different assumptions regarding the key biological HMS Medium Term Research Plan

13 parameters included in the model, although the analysis highlighted the need to refine some of these key parameters. The New Zealand catches represent 10% of the total. The stock is presently above the level necessary to produce the maximum sustainable yield. The WCPFC SC reported that Current catch levels from the South Pacific albacore stock appear to be sustainable and yield analyses suggest that increases in fishing mortality and yields are possible. However, given the age specific mortality of the longline fleets, any significant increase in effort would reduce CPUE to low levels with only moderate increases in yields. CPUE reductions may be more severe in areas of locally concentrated fishing effort. Bigeye Bigeye tuna are assessed as two stocks, one in the western and central Pacific Ocean (WCPO) and one in the eastern Pacific Ocean (EPO). Since the 1990 s total catches of bigeye from the Pacific Ocean are between 180,000 and 220,000 t per year. Both assessments are uncertain due to problems with catch statistics, nevertheless abundance in the EPO is estimated to have declined below the level that will support the MSY and current catches are not sustainable. The 2006 assessment for the WCPO stock was updated from 2005 and presented to the Commission. The 2006 assessment results were reviewed and confirmed as consistent with the 2005 assessment, although the point estimate for F current /F MSY was slightly more pessimistic in this assessment. The assessment using the 6 region model indicates that there is a high probability that overfishing of bigeye has been occurring in the WCPO (F current /F MSY 1, with >99% probability) since While the stock is not yet in an overfished state (B current /B MSY > 1, with >99% probability); further biomass decline is likely to occur at levels of fishing mortality at long-term average levels of recruitment, moving the stock into an overfished state. The greatest impact from the fishery is in the equatorial region, while the temperate regions are estimated to be moderately exploited. Furthermore, the attribution of depletion to various fisheries or groups of fisheries indicates that the longline fishery has the greatest impact; the purse seine fishery operating on associated sets has a lesser, but still substantial effect, particularly in the equatorial regions. New Zealand domestic catches represent 0.2% of the total removals from the stock. The stock is presently above the level necessary to produce the maximum sustainable yield. Current catches from the stock are not sustainable and will move the stock towards and then below a size that will support the maximum sustainable yield. Pacific bluefin The Interim Scientific Committee (ISC) is currently developing a detailed stock assessment for this stock. At this stage the assessment is preliminary and thus uncertain. It is not known if current catches are sustainable or will help the stock move toward the level that will support the MSY. There is concern about the high fishing mortality on juvenile fish. Skipjack Skipjack tuna are assessed as two stocks, one in the WCPO and one in EPO. Since the 1990 s total catches of skipjack from the Pacific Ocean have been between 964,000 and 1,482,000 t per year. The EPO assessment does not contain tagging information and is very uncertain, abundance is estimated to vary greatly from year to year with very little estimated impact of HMS Medium Term Research Plan

14 fishing on abundance. The WCPO is more reliable and also indicates that biomass is variable and that the reduction is abundance attributed to fishing is low. The 2nd meeting of the WCPFC provided the following summary on the status of the WCPO stock: No new assessment was conducted for skipjack in 2006 so there was no basis to modify the conclusions from The 2005 stock assessment indicates that for the skipjack stock in the WCPO over fishing is not occurring (F current / F MSY < 1), that the stock is not in an overfished state (B current / B MSY > 1) and that exploitation is modest relative to the stock s biological potential. Catches increased in 2005 from their previous historical high in These high catches are sustainable unless recruitment falls persistently below the long-term average. However, any increases in purse seine catches of skipjack may result in a corresponding increase in fishing mortality for yellowfin and bigeye tunas. The most recent assessment was undertaken in 2005 and covered the western and central Pacific stock. There are currently no concerns relating to the current status of this stock though there are concerns that any increases in fishing effort on this stock could adversely bigeye and yellowfin tuna. New Zealand catches represent 1.5% of the total catch. The stock is presently above the level necessary to produce the maximum sustainable yield. Current catches from the stock are likely to be sustainable. Current catches will move the stock towards a size that will support the maximum sustainable yield. Southern bluefin Southern bluefin tuna are assessed as a single Pacific Ocean/Indian Ocean/Tasman Sea stock, with the New Zealand catch accounting for approximately 2.5% of the global total. The CCSBT- Scientific Committee provided the following summary of the status of the stock: Because of the uncertainty in historical catch and CPUE a series of alternative scenarios that encompass a range of possible circumstances was evaluated. The outcomes of these scenarios and their management consequences are consistent with each other. The scenarios are also consistent with the 2005 SAG report regarding overall stock status and suggest the SBT spawning biomass is at a low fraction of its original biomass and well below the 1980 level as well as below the level that could produce maximum sustainable yield. Rebuilding the spawning stock biomass would almost certainly increase sustainable yield and provide security against unforeseen environmental events. Recruitments in the last decade are estimated to be well below the levels in the period All scenarios suggest that recruitment in the 1990s fluctuated with no overall trend. Analysis of several independent data sources and the scenarios indicate low recruitments in 2000 and 2001, and the scenarios suggest low recruitment in 2002 and 2003, although the low estimates of 2003 year class strength is inconsistent with the Japanese length frequency data from The most recent assessment was undertaken in 2005 and covered the entire stock. On a regional level there are concerns relating to the current status of this stock and the level of fishing effort. The stock is presently well below the level necessary to produce the maximum sustainable yield. The global catch limit has been set at a level considered to reduce the possibility of further decline in the stock and hopefully lead to rebuild. Yellowfin HMS Medium Term Research Plan

15 Yellowfin tuna are assessed as two stocks, one in the WCPO and one in EPO. Since the 1990 s total catches of yellowfin from the Pacific Ocean are between 593,000 and 889,000 t per year. Both assessments indicate that these stocks are near fully exploited. The 3 rd meeting of the WCPFC Scientific Committee provided the following summary on the status of the stock: The 2007 stock assessment conclusions differ slightly from the 2006 assessment, particularly in relation to the ratio of the current estimate of fishing mortality compared with the fishing mortality at maximum sustainable yield (F/F MSY ), with the threshold in the 2007 assessment being slightly more optimistic than that in the 2006 assessment. While the point estimate of F/F MSY remains slightly less than 1.0 (0.95), the probability distribution associated with the fishing mortality-based reference point indicates that there is almost an equal probability that the value of F/FMSY is less than or greater than the reference point. Therefore, the possibility of overfishing is still relatively high (47%). The reference points that predict the status of the stock under equilibrium conditions are B/B MSY (1.10) and SB/SB MSY (1.12), which indicate that the long-term average biomass would remain slightly above the level capable of producing MSY at average fishing mortality. Overall, current biomass exceeds the estimated biomass at MSY (B/BMSY >1.0) indicating that the yellowfin stock in the WCPO is not in an overfished state, although there is a small probability (6.2%) that it is in an overfished state (Figs. 3 4). The change in the estimated MSY in 2007 from that in 2006 may reflect changes in the data structure, fishery designations and levels of uncertainty in the assessment, especially in estimating absolute values, and the change in the scenarios modeled between years. New Zealand domestic catches represent 0.02% of the total WCPO catch (average ). Current catches from the stock are not sustainable. Current catches will move the stock towards and then below a size that will support the maximum sustainable yield. Research Approach and Information Requirements The stock assessment approaches for tuna are given in Table 18. The proposed levels of observer coverage and information to be collected by observers in relation to tuna species are given in Table 19. A chronology of tuna related research undertaken since 1995/1996 is given in Annex 10. Table 18: Tuna - current use of information and stock assessment approaches (items in italics are specifically related to the regional stock assessment). Species Albacore Bigeye Assessing stock status Monitoring catches, catch sampling, and a regional stock assessment Monitoring catches, catch sampling, and a regional stock assessment Information available Catch effort, length frequency data, abundance index for the domestic troll fishery, and tag recapture information Catch effort, length frequency data, and tag recapture information Stock assessment current MULTIFAN- CL assessment undertaken by the SPC in 2005/06 MULTIFAN- CL assessment undertaken by the SPC in 2005/06 Stock assessment future MULTIFAN- CL assessment undertaken by the SPC MULTIFAN- CL assessment undertaken by the SPC Research needs Continued catch monitoring Abundance index for the purse seine fishery in the tropical regions, domestic LL CPUE and continued catch monitoring Pacific Monitoring catches, Catch effort, length MULTIFAN-CL MULTIFAN-CL Abundance index for HMS Medium Term Research Plan

16 bluefin catch sampling, tagging, and a regional stock assessment frequency data, and tag recapture information assessment undertaken by the ISC assessment undertaken by the ISC Japanese troll fishery and continued catch monitoring Skipjack Monitoring catches, catch sampling, and a regional stock assessment Catch effort, length frequency data, and tag recapture information MULTIFAN- CL assessment undertaken by the SPC in 2004/05 MULTIFAN- CL assessment undertaken by the SPC Abundance index for the purse seine fishery in the tropical region and continued catch monitoring Southern bluefin Monitoring catches, catch sampling and tagging, and a regional stock assessment Catch effort, length frequency data, and tag recapture information Various assessment methods and analysis of indicator Management Procedure Tag recapture data and continued catch monitoring Yellowfin Monitoring catches, catch sampling, and a regional stock assessment Catch effort, length frequency data, and tag recapture information MULTIFAN- CL assessment undertaken by the SPC in 2005/06 MULTIFAN- CL assessment undertaken by the SPC in 2006/07 Abundance index for the purse seine fishery in the tropical region and continued catch monitoring Table 19: Tuna observer coverage Species Proportion of fishery to be covered Reason for coverage Information to be collected Albacore Longline: 827 target tuna longline days (459 domestic plus 368 charter) for 2008/09 Troll: 50 target albacore troll days To estimate catches of target species and of fish and non-fish bycatch as required under international obligations To describe the troll fishery, particularly with respect to potential measures of effort Bigeye Longline: 827 target tuna longline days To estimate catches of target species and of fish and non-fish bycatch as required under international obligations Pacific bluefin Skipjack Southern bluefin Longline: 827 target tuna longline days Purse seine: 170 target tuna purse seine days (70 small domestic, 30 super seiners in NZ waters, and 70 super-seiners outside NZ water) Longline: 10% of catch to be observed by fleet and area (part of 827 fleet-wide days) To estimate catches of target species and of fish and non-fish bycatch as required under international obligations To estimate catches of target species and of fish and non-fish bycatch as required under international obligations To estimate catches of target species and of fish and non-fish bycatch as required under international obligations Yellowfin Longline: 827 target tuna longline days To estimate catches of target species and of fish and non-fish bycatch as required under international obligations Catch estimates and biological samples and estimate non target catches Descriptions of operational procedures and interpretation of reporting requirements in the troll fishery Catch estimates and biological samples and estimate non target catches Catch estimates and biological samples and estimate non target catches Catch estimates and biological samples and estimate non target catches Catch estimates and biological samples and estimate non target catches Catch estimates and biological samples and estimate non target catches Implications for Research Sustainability Stock assessments for the major western and central Pacific Ocean tuna species are undertaken by the Oceanic Fisheries Program of the Secretariat of the Pacific Community (SPC), and have historically been reviewed by the Standing Committee for Tuna and Billfish (SCTB). HMS Medium Term Research Plan

17 The Western and Central Pacific Fisheries Commission (WCPFC) reviews assessments of these species (except southern bluefin). Southern bluefin tuna is assessed by Commission for the Conservation of Southern Bluefin Tuna (CCSBT). New Zealand participates in both the WCPFC and CCSBT. In New Zealand, research activities to date have largely been to determine catch and effort statistics for target tuna species, and developing standardised catch rate indices. The information, analyses, and reports provided by New Zealand form an important technical input for maintaining New Zealand access to the international tuna fisheries. As New Zealand is at the extreme southern range for most of these species, changes in fisheries in New Zealand fisheries waters may be important indicators for overall stock status. There is an ongoing need for: monitoring of landings and effects of fishing New Zealand fisheries waters; review of CPUE for key species in New Zealand fisheries waters every 2-3 years; monitoring the catch composition of major longline target species; catch sampling of albacore, as a contribution to the albacore stock assessment; contributions to the stock assessment of the major tuna species; production of fishery and status reports; and analyses on southern bluefin tuna as required by CCSBT. Effects of Fishing The New Zealand tuna longline fisheries often catch non-targeted species. Data from the Ministry of Fisheries Observer Programme are used to quantify the extent of fish bycatch caught on tuna longlines in New Zealand waters. The species most commonly recorded by observers are blue shark (Prionace glauca), albacore tuna, and Ray s bream (Brama brama). Other pelagic shark species are often taken as bycatch: porbeagle and school sharks have shown constant levels of catch in recent years. Mako sharks have been fairly consistent over recent years, though catches in were slightly higher than normal. Teleosts show a different pattern. Catches of oilfish, moonfish, and rudderfish have all increased recently. Tuna longline fishers (primarily domestic vessels) in northern waters also catch striped marlin but these are not retained. Both catch per unit effort and total estimated catch of this species show a great deal of inter-annual variability: there are no consistent trends. The CCSBT established an Ecologically Related Species Working Group (ERS-WG) to consider the impact of SBT fisheries on other species and the impacts of other species on SBT. Critical work from the ERS-WG has included work on mitigation of sea bird catches and considerable education materials for sea birds and sharks. Research has also been considered on trophic interactions that include SBT. There is considerable interest from conservation agencies regarding the incidental capture of protected species (in particular seabirds). The Ministry of Fisheries proposes to collect information on these catches and incidental captures and the factors that influence the catches and incidental capture levels. Research has also been undertaken (in the Aquatic Environment research area) to determine the levels of non-target fish and non-fish species taken as bycatch in tuna longline fisheries and the factors that influence these bycatch levels. HMS Medium Term Research Plan

18 Also, the larger tuna perform a role as apex predators in their environment and there are a variety of poorly understood issues relating to the removal of apex predators from pelagic ecosystems. Medium Term Research Plan for tuna Bold = research to be proposed for 2009/2010 Italic = multi-year research programme Species 2008/ / /11 Regular Albacore Bigeye Pacific bluefin Skipjack Southern bluefin Yellowfin Effects of fishing Troll CPUE Estimation of nonfish bycatch (seabirds) Full Age-at-maturity Full Full Full (including ex-nz waters Purse seine fleet) Full Catch-at-age Full Estimation of non-fish bycatch (e.g. seabirds, turtles, and marine mammals) RFMO summaries RFMO summaries RFMO summaries RFMO summaries RFMO summaries Catch-at-age RFMO summaries Estimation of non-fish bycatch (e.g. seabirds, turtles, and marine mammals) Full of tuna fisheries (every 4-5 years) RFMO summaries (annually) (annually) Troll CPUE (3 years) Full of tuna fisheries (4-5 years) RFMO summaries (annually) (annually) Full of tuna fisheries every (4-5 years) RFMO summaries (annually) (annually) Full of tuna fisheries (every 4-5 years) RFMO summaries (annually) (annually) Full of tuna fisheries (every 4-5 years) RFMO summaries (annually) (annually) Catch-at-age (annually) Full of tuna fisheries (every 4-5 years) RFMO summaries (annually) (annually) Full of tuna fisheries (every 4-5 years) Species 2004/ / / /2008 HMS Medium Term Research Plan

19 Albacore observers and produce status reports Fishery Fishery CPUE Stock assessment Bigeye observers and produce status reports Fishery Development of catch sampling programme Fishery Pacific bluefin observers and produce status reports Fishery Development of catch sampling programme Fishery Skipjack observers and produce status reports Fishery Development of catch sampling programme Analysis of purse-seine observer data Fishery Southern bluefin observers and produce status reports Within zone movements Fishery Within zone movements Development of catch sampling programme Fishery Analysis of electronic tagging data Catch-at-age Catch-at-age Within zone movements Yellowfin observers and produce status reports Fishery Development of catch sampling programme Fishery Characterisation of recreational fisheries Effects of fishing Estimation of non-target fish species in tuna longline fisheries Estimation of nonfish bycatch (seabirds) Estimation of nonfish bycatch (seabirds) Estimation of non-target fish species in tuna longline fisheries Estimation of nonfish bycatch (seabirds) Estimation of nonfish bycatch (seabirds) Trophic analysis of large pelagic fishes Species 2000/ / / /2004 Albacore observers and produce status reports observers and produce status reports observers and produce status reports observers and produce status reports Assess current and alternative stock assessments Bigeye observers and produce status reports observers and produce status reports observers and produce status reports observers and produce status reports Assess current and HMS Medium Term Research Plan

20 alternative stock assessments Pacific bluefin observers and produce status reports observers and produce status reports observers and produce status reports Skipjack observers and produce status reports observers and produce status reports observers and produce status reports observers and produce status reports Assess current and alternative stock assessments Southern bluefin observers and produce status reports observers and produce status reports observers and produce status reports observers and produce status reports Within zone movements Yellowfin observers and produce status reports observers and produce status reports observers and produce status reports observers and produce status reports Effects of fishing Estimation of nonfish bycatch (seabirds) Estimation of nonfish bycatch (seabirds) Estimation of nonfish bycatch (seabirds) Estimation of nonfish bycatch (seabirds) Estimation of factors influencing levels of nonfish bycatch Estimation of factors influencing levels of nonfish bycatch Estimation of factors influencing levels of nonfish bycatch Estimation of non-target fish species in tuna longline fisheries Estimation of non-target fish species in tuna longline fisheries Estimation of non-target fish species in tuna longline fisheries Estimation of factors influencing levels of nontarget fish bycatch Estimation of factors influencing levels of nontarget fish bycatch Estimation of factors influencing levels of nontarget fish bycatch Annex 10: Chronology of tuna research Year Project Objectives Reports 1995/96 PITU01: Characterise variation in albacore catches with respect to ocean features PITU06: Status reports on albacore, skipjack and SBT fisheriesmof603: Support for CCSBT PIPE01: Develop relative abundance indices from aerial sightings data SANF01: Assess the nonfish bycatch, especially seabirds, in longline fisheries 1996/97 Support for international Fishing Agreements PITU06: Continued 1. Real time monitoring on SBT. 2. Advice in support of international obligations. 3. Develop models of relative abundance of target tuna. 1. Updates of catch of ALB, BIG, SKJ, YFN and SBT. 2. Status report on albacore, bigeye and SBT. Murray, T., K. Richardson, H. Dean, and L. Griggs Fisheries for albacore, bigeye and southern bluefin tunas in the New Zealand EEZ and adjacent waters with an update on the status of the stocks. Contract report prepared for Ministry of Fisheries Project PITU06 (WLG 97/53). Taylor, P.R Standardising estimates of relative abundance from aerial sightings data using environmental data as predictors in linear regression. Draft NIWA Technical Report. Baird, S. J Bycatch of New Zealand fur seals (Arctocephalus fosteri) in trawl fisheries in New Zealand waters, to Draft N.Z. Fisheries Assessment Research Document 97/xx. xp. Baird, S. J., Report on the incidental capture of nonfish species during fishing operations in New Zealand waters. A Report from Ministry of Fisheries Research Project SANF01 HMS Medium Term Research Plan

21 PIPE01: Continued SANF01: Continued 1997/98 TUN9701: Produce reports on current tuna fisheries. ENV9701: Estimation of bycatch of non-target fish species in tuna longline fisheries in the New Zealand EEZ 3. Coordinate observer data for use in SBT stock assessments. 4. Use RTMP data in SBT assessments. 5. Update standardised CPUE for SBT. 6. Develop standardised CPUE for BIG longline fishery. 1. Processing and analysis of data. 2. Marine mammal and sea-bird carcass recovery. 3. Research to mitigate mammal seabird catch. 1. Size composition, discards, sex ratio and lengthweight of albacore, bigeye, SBT from Scientific Observers and other sources. 2. Update the standardised CPUE for bigeye and SBT. 1. To estimate the total numbers of captures, releases, and deaths of nonfish bycatch species in fishing operations for the to fishing years, specifically: seabirds by species, by fishery, by area (QMA) and by specified time period (e.g. week, month); New Zealand sea lions in the southern squid trawl (SQU 6T and the area adjacent to the Snares Islands), scampi and southern blue whiting fisheries, by area, specified time period (e.g. week, month), and sex; New Zealand fur seals in bottom and midwater trawl fisheries by fishery, area (QMA), specified time period (e.g. week, month), and sex; dolphins in bottom and midwater trawl fisheries by area (QMA) and specified time period (e.g. week, month). Murray, T Stock assessment of tunas in support of New Zealand s international fishing agreements. Progress Report for Ministry of Fisheries Research Project TUN9701. obj. 1. Baird, S.J Estimation of nonfish bycatch in commercial fisheries in New Zealand waters, to Final Research Report for Ministry of Fisheries Research Project ENV9701. obj. 1. Baird, S.J., B.M. Sanders, H.A. Dean, and L.H. Griggs Estimation of nonfish bycatch in commercial fisheries in New Zealand waters, to Final Research Report for Ministry of Fisheries Research Project ENV9701. obj. 1(Revised version January 1999). 1998/99 TUN9801: Stock assessment of tunas and swordfish in support of New Zealand s international fishing agreements See also ENV /00 TUN1999/02: Monitor the stocks of southern bluefin tuna in the New Zealand EEZ and adjacent areas to provide information in support on New Zealand s international fishing agreements See also TUN1999/01 1. To produce reports on the current fisheries around New Zealand for albacore, bigeye, skipjack, southern bluefin and yellowfin tuna, and swordfish. 2. To determine size composition, discards, sex ratio, and length-weight relationships of albacore, bigeye, southern bluefin and yellowfin tuna, and swordfish from biological data collected by Scientific Observers and from other sources during the 1997/98 fishing year for use as inputs to characterise and assess the New Zealand tuna fisheries. 3. To update the standardised CPUE analysis for albacore, bigeye and southern bluefin tuna with the inclusion of data from the 1997/98 fishing year. 4. To determine size composition, sex ratio, and length-weight relationships of albacore tuna during the 1998/99 fishing year from samples collected in fish sheds. 1. Produce a country report on the status of New Zealand fisheries for southern bluefin tuna for the 1999 and 2000 fishing years. 2. Produce a standardised CPUE analysis and report for CCBST on southern bluefin tuna for the 1999 and 2000 fishing years respectively. Baird, S.J Determination of factors which affect nonfish bycatch in some New Zealand fisheries. Final Research Report for Ministry of Fisheries Research Project ENV9701. obj. 3. Griggs, L., Murray, T Determination of size composition, sex ratio, and length:weight relationships of albacore tuna during the fishing year from samples collected in fish sheds. Final Research Report for Ministry of Fisheries Research Project TUN9801. Murray, T., Griggs, L., Dean, H New Zealand Domestic Tuna Fisheries to Final Research Report for Ministry of Fisheries Research Project TUN1999/01. obj. 1. Richardson, K., T. Murray, and H. Dean Models for southern bluefin tuna in the New Zealand EEZ New Zealand Fisheries HMS Medium Term Research Plan

22 2000/01 TUN2000/01: Monitoring the length structure of commercial landings of albacore in support of New Zealand/s international fishing agreements MOF2000/02B: Identification of northern bluefin tuna in the New Zealand EEZ. MOF H: Northern Bluefin DNA Sampling and Identification See also PEL2000/ /02 TUN2001/02: Monitoring the length structure of commercial landings of albacore in support of New Zealand s international fishing agreements MOF D: Analysis of Southern Bluefin Tuna Fishing Data See also PEL2001/01, TUN2001/ /03 TUN2002/03: Stock assessment of Albacore tuna 2003/04 TUN2003/02: Characterisation of the New Zealand Tuna Fisheries 1. To determine and report the length composition and length-weight relationships of albacore tuna during the 2000/2001 fishing year from samples collected in fish sheds. The target coefficient of variation (c.v.) for the length composition is 30% (mean weighted c.v. across all length classes). 1. Based on the hypothesis that the absence of the "bust" is a reliable and practical method of distinguishing northern bluefin in New Zealand the following activities will be carried out: 2. Collate the information on field characters and DNA markers used to identify the suspect NBT. 1. Using genetic samples (DNA) to determine whether commercially caught bluefin tuna are southern bluefin tuna, or pacific bluefin tuna. 1. To conduct sampling in fish sheds and determine and report the length composition and lengthweight relationships of albacore tuna during the 2001/02 fishing year from samples collected in fish sheds. The target coefficient of variation (c.v.) for the length composition is 30% (mean weighted c.v. across all length classes). 2. As for 1) for the 2002/03 fishing year. 1. To obtain an estimate of the instantaneous fishing effort and bycatch rate as a function of the time of year, time of day, location, and mitigation measure used. 1. To review and summarise the historical biological data (including length frequency, sex ratio, age, and reproductive condition data) for albacore collected by the MFish Observer Programme, shed sampling programmes and other sources since the start of these programmes and evaluate the use of these data as inputs into stock assessments. 2. To update analyses of length frequency, sex ratio, and reproductive condition data for albacore collected by the MFish Observer Programme, shed sampling programmes and other sources up to December To develop standardised CPUE indices for troll caught and longline caught albacore and contrast their performance relative to nominal CPUE. 4. To describe approaches to the development of a stock assessment, including estimating biomass and sustainable yields for albacore in the New Zealand EEZ. 1. To characterise the New Zealand tuna fisheries for albacore (Thunnus alalunga), bigeye tuna (T. obesus), Pacific bluefin tuna (T. orientalis), skipjack tuna (Katsuwonus pelamis), southern bluefin tuna (Thunnus maccoyii), yellowfin tuna (T. albacares), and swordfish (Xiphias gladius) in the New Zealand EEZ and adjacent areas for the 2002/03 fishing year. 2. As for 1) for the 2003/04 fishing year. Assessment Report 2001/18. 21p Griggs, L.H.; Richardson, K. (2005). New Zealand tuna fisheries, 2001 and New Zealand Fisheries Assessment Report 2005/4. 58p. Griggs, L. and T. Murray Monitoring the length structure of commercial landings of albacore tuna during the fishing year. Final Research Report for Ministry of Fisheries Research Project TUN2000/01. Smith, P., Griggs, L Identification of northern bluefin tuna in the New Zealand EEZ. Final Research Report for Ministry of Fisheries Research Project MOF2000/02B. obj. 1. Griggs, L Monitoring the length structure of commercial landings of albacore tuna during the fishing year. Final Research Report for Ministry of Fisheries Research Project TUN2001/02. Murray, T. (2005). The distribution of Pacific bluefin tuna (Thunnus orientalis) in the southwest Pacific Ocean, with emphasis on New Zealand waters. New Zealand Fisheries Assessment Report 2005/42, 14p. Kendrick, T. (2006) Characterisation of the New Zealand tuna fisheries in and New Zealand Fisheries Assessment Report 2006/28 HMS Medium Term Research Plan

23 ALB2003/01: Stock Monitoring of Albacore See also TUN2003/ /05 See also TUN2004/01, OBS2004/ /06 TUN2005/01: Characterisation of the New Zealand tuna fisheries TUN2005/02: Development of a commercial catch sampling programme for highly migratory fish species ALB 2005/01: Stock monitoring of albacore See also PEL2005/01, OBS2005/ /07 STN2006/01: Catch at age of southern bluefin tuna. 1. To conduct sampling in fish sheds and determine and report the length composition and lengthweight relationships of albacore tuna during the 2003/2004 fishing year from samples collected in fish sheds. The target coefficient of variation (c.v.) for the length composition is 20 % (mean weighted c.v. across all length classes). 2. As for 1) for the 2004/2005 fishing year. 1. To characterise the New Zealand tuna fisheries for albacore (Thunnus alalunga), bigeye tuna (Thunnus obesus), Pacific bluefin tuna (Thunnus orientalis), skipjack tuna (Katsuwonus pelamis), southern bluefin tuna (Thunnus maccoyii), yellowfin tuna (Thunnus albacares), and swordfish (Xiphias gladius) in the New Zealand fisheries waters and adjacent areas for the 2004/05 fishing year. 2. To characterise the New Zealand tuna fisheries for albacore (T. alalunga), bigeye tuna (T. obesus), Pacific bluefin tuna (T. orientalis), skipjack tuna (K. pelamis), southern bluefin tuna (T. maccoyii), yellowfin tuna (T. albacares), and swordfish (X. gladius) in the New Zealand fisheries waters and adjacent areas for the 2005/06 fishing year. 1. To develop and implement a shore-based biological catch sampling programme for swordfish. 2. To describe methods for application of a broad scale shore-based catch sampling programme for all highly migratory fish species. 1. To conduct sampling in fish sheds and determine and report the length composition and lengthweight relationships of albacore tuna during the 2005/2006 fishing year from samples collected in fish sheds. The target coefficient of variation (c.v.) for the length composition is 20 % (mean weighted c.v. across all length classes). 2. To conduct sampling in fish sheds and determine and report the length composition and lengthweight relationships of albacore tuna during the 2006/2007 fishing year from samples collected in fish sheds. The target coefficient of variation (c.v.) for the length composition is 20 % (mean weighted c.v. across all length classes). 3. To conduct sampling in fish sheds and determine and report the length composition and lengthweight relationships of albacore tuna during the 2007/2008 fishing year from samples collected in fish sheds. The target coefficient of variation (c.v.) for the length composition is 20 % (mean weighted c.v. across all length classes). 4. To collect 50 pairs of otoliths from fish of 50 cm fork length or less per fishing year. 1. To age 250 otoliths per year from southern bluefin tuna collected by scientific observers aboard vessels fishing in New Zealand fisheries waters during the 1998/99 to 2000/01 fishing seasons. 2. To age 250 otoliths from southern bluefin tuna collected by scientific observers aboard vessels fishing in New Zealand fisheries waters during the 2004/05 fishing season. Griggs, L. (2004). Monitoring the length structure of New Zealand commercial landings of albacore tuna during the fishing year. Final Research Report for project ALB2003/01, Objective 1 Griggs, L.H., Baird, S.J., Francis, M.P. (2007). Fish bycatch in New Zealand tuna longline fisheries, to New Zealand Fisheries Assessment Report 2007/ p. HMS Medium Term Research Plan

24 3. To age 250 otoliths from southern bluefin tuna collected by scientific observers aboard vessels fishing in New Zealand fisheries waters during the 2005/06 fishing season. TUN2006/01: Commercial catch sampling programme for highly migratory species 1. To continue the shore-based catch sampling programme for swordfish for the 2006/07 fishing year 2. To undertake shore-based catch sampling for other highly migratory species for the 2006/07 fishing year. TUN2006/02: Estimation of non-target fish catches in the tuna longline fishery 1. To estimate the catches, catch rates, and discards of non-target fish in tuna longline fisheries data from the Observer Programme and commercial fishing returns for the 2005/06 fishing year. 2. To describe bycatch trends in tuna longline fisheries using data from this project and the results of previous similar projects. See also PEL2006/02, OBS2006/ /08 STN2007/01: Catch at age of southern bluefin tuna 1. To age 250 otoliths per year from southern bluefin tuna collected by scientific observers aboard vessels fishing in New Zealand fisheries waters during the 2006/07 fishing season. 2. To age 250 otoliths from southern bluefin tuna collected by scientific observers aboard vessels fishing in New Zealand fisheries waters during the 2007/08 fishing season. TUN2007/01: Characterisation of New Zealand tuna fisheries for International obligations 1. To characterise the New Zealand tuna fisheries for albacore (Thunnus alalunga), bigeye tuna (Thunnus obesus), Pacific bluefin tuna (Thunnus orientalis), skipjack tuna (Katsuwonus pelamis), southern bluefin tuna (Thunnus maccoyii), yellowfin tuna (Thunnus albacares), and swordfish (Xiphias gladius) in the New Zealand fisheries waters and adjacent areas for the 2006/07 fishing year and 2007 calendar year. 2. To estimate the catches, catch rates, and discards of non-target fish in tuna longline fisheries data from the Observer Programme and commercial fishing returns for the 2006/07 fishing year and 2007 calendar year. 3. To characterise the New Zealand tuna fisheries for albacore (T. alalunga), bigeye tuna (T. obesus), Pacific bluefin tuna (T. orientalis), skipjack tuna (K. pelamis), southern bluefin tuna (T. maccoyii), yellowfin tuna (T. albacares), and swordfish (X. gladius) in the New Zealand fisheries waters and adjacent areas for the 2007/08 fishing year and 2008 calendar year. 4. To estimate the catches, catch rates, and discards of non-target fish in tuna longline fisheries data from the Observer Programme and commercial fishing returns for the 2007/08 fishing year and 2008 calendar year. TUN2007/02: Commercial catch sampling programme for highly migratory fish species 1. To continue the shore-based catch sampling programme for swordfish, southern bluefin tuna, bigeye tuna, Pacific bluefin tuna, and yellowfin for the 2007/08 fishing year HMS Medium Term Research Plan

25 2. To continue the shore-based catch sampling programme for swordfish, southern bluefin tuna, bigeye tuna, Pacific bluefin tuna, and yellowfin for the 2008/09 fishing year HMS Medium Term Research Plan

26 BILLFISH Black marlin (Makaira indica), blue marlin (Makaira mazara), striped marlin (Tetrapturus audax), shortbill spearfish (Tetrapturus angustirostris), and swordfish (Xiphias gladius) The Fisheries Swordfish (Xiphias gladius) were introduced into the QMS on 1 October 2004 under a single fishstock SWO 1. In 1988 a prohibition on the commercial taking of striped marlin, blue marlin, black marlin, swordfish, shortbill spearfish sailfish and any other billfish was applied in the waters of the Auckland Fishery Management Area. In 1991 an amendment to regulations removed swordfish from this prohibition. Also in 1991 a prohibition on the commercial take of striped marlin, blue marlin and black marlin was applied to all New Zealand fisheries waters. The prohibition on the commercial taking of shortbill spearfish, sailfish and any other billfish still applies in the Auckland Fisheries Management Area. Management of swordfish and other billfish throughout the western and central Pacific Ocean (WCPO) is the responsibility of the Western and Central Pacific Fisheries Commission (WCPFC). At its third annual meeting (2006) the WCPFC passed separate Conservation and Management Measures (CMMs) (binding measures that all parties must abide by) relating to conservation and management of swordfish and striped marlin in the southwest Pacific Ocean ( These measure restricts the number of vessels fishing for swordfish and striped marlin in the convention area south of 20 degrees south. New Zealand existing efforts to conserve billfish through its commercial moratorium were noted in the development of the striped marlin measure. Commercial Commercial fishers can land swordfish and landings of swordfish from pelagic longline fisheries have risen rapidly in recent years. There is also a small by-catch of swordfish in the HMS Medium Term Research Plan

27 arrow squid target trawl fishery. Over 90% of the commercial landings of swordfish have come from FMA 1 (41%), FMA 2 (38%), and FMA 3 (13%). TACs (t), current reported landings (t), and TACCs (t) are: FMAs SWO 1 All TAC 919 TACC yr range For the marlin species, reliable estimates of longline catches based on observer data are only available for striped marlin as the other species are only very rarely encountered. The estimated number of striped marlin caught (these fish are not retained) in the longline fishery estimated from observer data range from fish over the past five years. Based on an average size for striped marlin in New Zealand waters of 104 kg (J Holdsworth, Blue Water Marine Research, unpublished data), the annual total catch of striped marlin in New Zealand has probably ranged from tonnes over the past five years. As described above, with only a few exceptions, none of the marlins are allowed to be landed by commercial fishers in New Zealand fisheries waters. Some incidental catch, in particular of striped marlin, does occur in pelagic longline fisheries and is quantified below. The recent commercial landings, by calendar year, for billfishes estimated in the western and central Pacific Ocean (WCPO) are: Recreational Species Striped Marlin Blue marlin Black marlin Swordfish Area WCPO WCPO WCPO WCPO 5 yr range In New Zealand waters the marlins are the focus of an important gamefish fishery. Striped marlin are targeted and caught in moderate numbers each year although annual variations in summer oceanographic conditions cause wide fluctuations in catch levels. The other marlins are generally infrequently caught as non-target catch when fishers are targeting striped marlin, although some low level of targeting does occur. Swordfish is the focus of a small but developing target fishery and is considered a highly prized target by some recreational anglers. An allowance of 20t was set for recreational catch as part of the introduction of swordfish into the QMS. A recreational allowance has not been set for any of the marlin species to date. Recreational catches are moderately well know, especially those fish landed through gamefishing clubs which are thought to make up the majority of the recreational catch of these species. Data from gamefishing clubs indicate that annual striped marlin catch has ranged from fish per annum over the past decade catches. Up to 50% of these fish are tagged and released. Recreational catches are assumed to be high in the context of the overall New Zealand stock removals for all billfish except swordfish. For swordfish, recreational catches are small in the context of the overall New Zealand stock removals. Customary non-commercial An allowance of 10t was set for customary use as part of the introduction of swordfish into the QMS. A customary allowance has not been set for any of the marlin species to date. HMS Medium Term Research Plan

28 There is no information available to allow estimation of the amounts of billfishes taken in the traditional Mäori fishery, but catches are assumed small in the context of the overall removals. Stock Status Black marlin This species is believed to consist of two or three stocks, one in the eastern Pacific Ocean and one or two in the western Pacific Ocean, on the basis of fishery data and close proximity to shore of areas with high catch rates. There is no current stock assessment for this species so it is not known if current removals are sustainable across the Pacific. Blue marlin Biological and fishery data indicate that there is a single stock of blue marlin in the Pacific Ocean. This assumption is currently used in analyses of the stock status. The most recent Pacific wide stock assessment, though uncertain, indicates that the stock has been relatively stable about the MSY level since 1970 suggesting that current Pacific wide removals are likely to be sustainable. Striped marlin The stock structure of striped marlin in the Pacific Ocean is not well known, but the focus of current research activities. The two most frequently considered hypotheses are: (1) a singleunit stock in the Pacific, which is supported by the continuous horseshoe-shaped distribution of striped marlin; and (2) a two-stock structure, with the stocks separated roughly at the Equator, albeit with some intermixing in the eastern Pacific. The first attempt to carry out an assessment for this stock was undertaken in It was noted that the results should be considered preliminary as there remains significant uncertainty regarding the most important parameters of the model. In the absence of other assessments for this stock the following two paragraphs were developed by the WCPFC Scientific Committee on the basis of the results of the preliminary assessment: Several of the plausible model scenarios investigated indicate that current levels of fishing mortality may approximate or exceed the reference level FMSY and current spawning biomass levels may approximate or be below the biomass based reference point BMSY. On the basis of this preliminary assessment, it is recommended as a precautionary measure that there should be no increase in fishing mortality (i.e. fishing effort) on striped marlin in the southwestern Pacific. This recommendation applies particularly to the area encompassing the Coral Sea and the Tasman Sea as these fisheries account for most of the striped marlin catch in the southwest Pacific. Swordfish It is not known if there are one or several stocks of swordfish in the South Pacific. Catches of swordfish since the 1980s have been relatively stable in the western central Pacific Ocean. Swordfish are caught by tuna longliners throughout the Western and Central Pacific Ocean, usually as non-target catch in pelagic longline fisheries for tuna, though some target fisheries do exist, e.g. Australia. Catch rates in New Zealand fisheries waters have until recently been low (due to the non-target catch nature of the fishery) and stable. HMS Medium Term Research Plan

29 In 2006 the WCPFC Scientific Committee reviewed the first regional assessment undertaken for swordfish in the southwestern Pacific region. Although the estimates of stock status relative to standard biological reference points (e.g. B current /B 0 or B MSY ) could not identify whether the stock was presently overfished or not, this assessment has indicated consistent declines in stock abundance in recent years, and most model projections predict further declines at current levels of fishing mortality. Until estimates of stock status are more certain, the Scientific Committee recommended as a precautionary measure that there be no increases in fishing mortality on this stock, as this is likely to move the stock towards an overfished state. This recommendation applies particularly to the area encompassing the western component of the southwest Pacific as these fisheries account for most of the swordfish catch in the southwest Pacific. It is not currently possible to estimate a long-term sustainable yield for swordfish, or to determine if recent catch levels will allow the stock(s) to move towards a size that would support a MSY. Research Approach and Information Requirements The stock assessment approaches for billfishes are given in Table 14. The proposed levels of observer coverage and information to be collected by observers in relation to billfishes are given in Table 15. A chronology of billfish related research undertaken since 1995/1996 is given in Annex 8. Table 14: Billfish - current use of information and stock assessment approaches (items in italics are specifically related to the regional stock assessment). Species Assessing stock status Information available Stock assessment current Stock assessment future Research needs Black marlin Monitor catches Catch, size composition -n/a- Assessment of the wider stocks maybe undertaken in international settings. Stock structure Blue marlin Monitor catches Catch, size composition A historical Pacific wide assessment using MULTIFAN- CL This assessment will likely be updated in the future in international settings. Stock structure, and standardized CPUE Striped marlin Regional stock assessment and domestic recreational CPUE (logbook programme) Catch, size composition, recreational CPUE Preliminary assessment for SW Pacific undertaken in Unknown Stock structure, catch monitoring, standardized CPUE, and age and growth Swordfish Regional stock assessment and local catch sampling Catch, effort, and size composition Full assessment for SW Pacific undertaken in Joint NZ/AUS assessment in 2008/09 Relative abundance estimates, catch monitoring, and stock assessment Table 15: Billfish observer coverage Species Proportion of fishery to be covered Reason for coverage Information to be collected Black marlin Longline no specific marlin days, but catch sampling to be linked to the 733 days of target tuna longline coverage. To estimate catch Catch, size composition of catch, and fate of released individuals. Purse seine no specific marlin days, but catch sampling HMS Medium Term Research Plan

30 to be linked to the 210 days of target tuna purse seine coverage. Blue marlin Longline no specific marlin days, but catch sampling to be linked to the 733 days of target tuna longline coverage. To estimate catch Catch, size composition of catch, and fate of released individuals. Purse seine no specific marlin days, but catch sampling to be linked to the 210 days of target tuna purse seine coverage. Striped marlin Longline no specific marlin days, but catch sampling to be linked to the 733 days of target tuna longline coverage. Purse seine no specific marlin days, but catch sampling to be linked to the 210 days of target tuna purse seine coverage. To estimate catch, collect biological data and biological samples for age and growth research Catch, size composition of catch, and fate of released individuals. Swordfish Longline no specific swordfish days, but catch sampling to be linked to the 733 days of target tuna longline coverage and elsewhere as possible especially in midwater trawl fisheries. To estimate catch, record catch composition, processed weights, and detailed effort information Catch and effort, size composition of catch, and biological samples. Implications for Research Sustainability Billfish that occur (generally seasonally) within New Zealand fisheries waters represent important recreational and commercial (for swordfish) fisheries. Swordfish were introduced into the QMS on 1 October 2004, but the other billfish species are not being considered for the QMS at this time. It is proposed that swordfish will be introduced onto the Sixth Schedule of the 1996 Fisheries Act with an allowance to return small individuals to the water if there are in good condition this will have implications for future research and presents an opportunity for a fishery based tagging programme. Stock structure is generally poorly known for these species and stock assessments are only available for blue marlin at this time though the first regional assessments for swordfish and striped marlin are near completion. Thus, stock status of these species is largely unknown. For striped marlin, the fish caught in New Zealand represent some of the largest individuals encountered in the Pacific and therefore are of considerable interest for stock assessmentrelated research. As New Zealand catches for these species are low in terms of overall stock removals it is unlikely that New Zealand will undertake its own assessments or take a lead role in regional-level assessments, however, well directed research (e.g., stock structure and growth studies) and continued monitoring of commercial and recreational catches and landings, will allow New Zealand to contribute to future stock assessment processes. Effects of Fishing Juvenile habitat and adult spawning grounds have not been identified within New Zealand fisheries waters for these species. Sub-adult swordfish occur in New Zealand fisheries waters, but most of the marlins taken in the zone are adult fish. As noted above, billfishes are generally taken as bycatch of target tuna longline fisheries. As marlins cannot be retained, these must be returned to the water dead or alive. Pelagic longlines also catch a range of fish and non-fish bycatch and assessing the status and productivity of the major bycatch species is the focus of considerable current research. Also, billfishes perform a role as apex predators in their environment and there are a variety of poorly understood issues relating to the removal of apex predators from pelagic ecosystems. In 2006/07 a target fishery for swordfish developed which was based around shallow setting of longlines during daylight hours. On some vessels using this approach, large bycatch of albatrosses were taken. This led to the a ban on the setting of surface longlines during HMS Medium Term Research Plan

31 daylight hours. MFish is currently working with commercial fishers to consider the best approach to mitigate seabird bycatch. There is considerable interest from conservation agencies regarding the non-target catch from tuna fishing (in particular billfish and sharks) and the incidental capture of protected species (in particular seabirds). The Ministry of Fisheries proposes to collect information on these catches and incidental captures and the factors that influence the catches and incidental capture levels. Research has also been undertaken (in the Aquatic Environment research area) to determine the levels of non-target fish and non-fish species taken as bycatch in tuna longline fisheries and the factors that influence these bycatch levels. Medium Term Research Plan for Billfish Bold = research to be proposed for 2009/2010 Italic = multi-year research programme Species 2008/ /2010 Annual Regular Black marlin Blue marlin Shortbill spearfish Striped marlin Swordfish All billfish No research at this time annual New Zealand fisheries waters catch by all methods assumed less than 100 fish No research at this time annual New Zealand fisheries waters catch by all methods assumed less than 200 fish No research at this time annual New Zealand fisheries waters catch by all methods assumed less than 200 fish Gamefish Tag Recapture Programme Logbook and recreational catch monitoring Logbook and recreational catch monitoring Gamefish Tag Recapture Programme Full Logbook and recreational catch monitoring Full Analysis of tagging data Reducing uncertainty in the stock assessment Full Logbook and recreational catch monitoring Gamefish Tag Recapture Programme Logbook and recreational catch monitoring Logbook and recreational catch monitoring Full of tuna fisheries (every 4-5 years) Gamefish Tag Recapture Programme (annually) (annually) Logbook and recreational catch monitoring (annually) Full of tuna fisheries (every 4-5 years) (annually) (annually)cpue and stock assessment (every 3-4 years) Full of tuna fisheries (every 4-5 years) Species 2004/ / / /2008 Black marlin Blue marlin Shortbill spearfish Striped marlin No research at this time annual New Zealand fisheries waters catch by all methods assumed less than 100 fish No research at this time annual New Zealand fisheries waters catch by all methods assumed less than 200 fish No research at this time annual New Zealand fisheries waters catch by all methods assumed less than 200 fish Gamefish Tag Recapture Commercial catch estimates from observer Gamefish Tag Recapture Programme Standardised CPUE Gamefish Tag Recapture Programme Stock monitoring of Gamefish Tag Recapture Programme HMS Medium Term Research Plan

32 Swordfish data Stock monitoring recreational catches Fishery Stock assessment Fishery of commercial landings Stock assessment Stock structure and habitat use Fishery of commercial landings Stock structure Logbook and recreational catch monitoring Stock assessment All billfish Gamefish harvest estimates Gamefish tag programme review Observer data Estimation of non-target fish species in tuna longline fisheries Estimation of non-fish bycatch (seabirds) Gamefish Tag Recapture Programme Logbook and recreational catch monitoring Species 2000/ / / /2004 Black marlin Blue marlin Shortbill spearfish Striped marlin Swordfish No research at this time annual New Zealand fisheries waters catch by all methods assumed less than 100 fish No research at this time annual New Zealand fisheries waters catch by all methods assumed less than 200 fish No research at this time annual New Zealand fisheries waters catch by all methods assumed less than 200 fish Gamefish Tag Recapture Programme logbooks and observers and produce status reports Gamefish Tag Recapture Programme Factors affecting CPUE logbooks and observers and produce status reports Gamefish Tag Recapture Programme Commercial catch estimates from observer data Age & growth Stock structure logbooks and observers and produce status reports Gamefish Tag Recapture Programme Fishery Fishery Standardised CPUE Annex 8: Chronology of billfish research Year Project Objectives Reports 1995/96 PITU06: Status reports on albacore, skipjack and SBT fisheries AKGF01: Movement and growth of swordfish from tagging 1997/98 BIL9701: Update database containing movement and growth of billfish incl. swordfish from tagging 1. Assess effectiveness of Billfish Moratorium. 1. To review the results of collaborative research into the use of satellite and archival tagging techniques for estimating movement of billfish within and beyond New Zealand s EEZ and the residence time of striped marlin in New Zealand waters. 2. To determine the growth of kingfish from tagging data. 3. To determine the movement of kingfish and mako and blue sharks from tagging Murray, T., K. Richardson, H. Dean, and L. Griggs Fisheries for albacore, bigeye and southern bluefin tunas in the New Zealand EEZ and adjacent waters with an update on the status of the stocks. Contract report prepared for Ministry of Fisheries Project PITU06 (WLG 97/53). Holdsworth, J. and P. Saul Billfish and gamefish and movement annual report, Annual Report for Ministry of Fisheries Research Project AKGF01. Hartill, B., Davies, N. M New Zealand billfish and gamefish tagging, Final Research Report for Ministry of Fisheries Research Project BIL9701. Francis, M. P., Griggs, L. H., Baird, S. J., Murray, T. E., Dean, H Bycatch of non-target fish species in New Zealand tuna longline fisheries. Final Research Report for Ministry of Fisheries Project HMS Medium Term Research Plan

33 ENV9702: Determine the species and level of bycatch from tuna longline fisheries /99 TUN9801: Produce reports on current tuna fisheries DMAN : Billfish and Gamefish Database Upgrade and Tagging Administration See also ENV /00 TUN : Monitor the stocks of albacore, bigeye, skipjack and yellowfin tuna, and swordfish in the New Zealand EEZ and adjacent areas to provide information in support of New Zealand s international fishing agreements 2000/01 See also PEL2000/ /02 SWO2001/01: Factors affecting swordfish CPUE TUN2001/01: Monitoring albacore, bigeye, skipjack, southern bluefin and yellowfin tuna and swordfish in support of New Zealand/s international fishing agreements 2002/03 SWO2002/01: Swordfish structure. See also ENV2002/ /04 STM2003/01: Characterisation of the Striped Marlin Fishery TUN2003/01: Productivity of Important Non-target Species Caught in the Tuna Longline Fishery See also PEL2003/ /05 SWO 2003/01: Swordfish stock assessment data. 4. To update the tagging database with the inclusion of data for the 1997/98 year. 1. Estimate total catch and discard of marlin sp. taken by tuna longliners 1. Size composition, discards, sex ratio and length-weight of albacore, bigeye, SBT, yellowfin and swordfish from observers and other sources. 1. Billfish and Gamefish Database Upgrade and Tagging Administration 1. Produce a report on the status of New Zealand fisheries for albacore, bigeye, skipjack and yellowfin and southern bluefin tuna and swordfish for the 1998/1999 and 1999/2000 fishing years respectively. 1. To analyse available information and determine if catch per unit effort data can be used to obtain a relative index of abundance for swordfish in the New Zealand EEZ. 2. Mark recommendations on methods with which the status of swordfish can be monitored. 1. To produce reports on the New Zealand fisheries for albacore, bigeye, skipjack, southern bluefin and yellowfin tuna and swordfish for the 2001 and 2002 calendar years. 2. To characterise the catch of northern bluefin tuna (Thunnus orientalis) in the New Zealand EEZ by analysing data from the commercial fishery and other sources 1. To determine the stock structure of NZ EEZ swordfish in relation to the surrounding western Pacific/wider Pacific 'stocks' of swordfish. 2. To determine the residency of the swordfish stock caught as non-target catch in commercial longline fisheries in the New Zealand EEZ. 1. To characterise the New Zealand fishery for striped marlin. 1. To determine the growth rate, age at maturity, longevity and natural mortality rate of moonfish (Lampris guttatus). 2. To determine the growth rate, age at maturity, longevity and natural mortality rate of Ray s bream (Brama brama). 3. To determine the growth rate, age at maturity, longevity and natural mortality rate of swordfish (Xiphias gladius). 1. To review and summarise the historical biological data (including length frequency, sex ratio, age, and reproductive condition data) for swordfish collected by the MFish Observer Programme and other sources since the start of these programmes and ENV9702. Griggs, L., Murray, T Determination of size composition, sex ratio, and length:weight relationships of albacore tuna during the fishing year from samples collected in fish sheds. Final Research Report for Ministry of Fisheries Research Project TUN9801. Murray, T., Griggs, L., Dean, H New Zealand Domestic Tuna Fisheries, to Final Research Report for Ministry of Fisheries Research Project TUN1999/01. obj. 1. Francis, M.P.; Griggs, L.H.; Baird, S.J. (2004). Fish bycatch in New Zealand tuna longline fisheries, to New Zealand Fisheries Assessment Report 2004/22. 62p. Griggs, L.H.; Richardson, K. (2005). New Zealand tuna fisheries, 2001 and New Zealand Fisheries Assessment Report 2005/ p. Smith, P. J., Diggles, B., and Kim, S. (2005). Swordfish stock structure. Final Research Report for Ministry of Fisheries Project SWO2002/01 Objective 1 Holdsworth, J.; Kopf, R.K. (2005). Characterisation of striped marlin fisheries in New Zealand. New Zealand Fisheries Assessment Report 2005/ p. Griggs, L., Francis, M. P., and Ó Maolagáin, C. (2005). Growth rate, age at maturity, longevity and natural mortality rate of swordfish (Xiphias gladius). New Zealand Fisheries Assessment Report 2005/ p. Unwin, M., Richardson, K. Davies, N., Uddstrom, M., Griggs, L. & Wei, F Standardised CPUE indives for swordfish (Xiphias gladius) from the tuna longline fishery to using environmental variables. Final Research HMS Medium Term Research Plan

34 TUN2004/01: Estimation of nontarget fish catches in the tuna longline fishery SWO 2004/01: Swordfish stock assessment See also REC2004/02, OBS2004/05, REC2004/ /06 STM2005/01: Stock monitoring of striped marlin evaluate the use of these data as inputs into stock assessments. 2. To update analyses length frequency, sex ratio, and reproductive condition data for swordfish collected by the MFish Observer Programme, shed sampling programmes and other sources up to December To develop standardised CPUE indices for longline caught swordfish and contrast its performance relative to nominal CPUE. 4. To develop a stock assessment, including estimating biomass and sustainable yields for swordfish in the New Zealand EEZ. 1. To estimate the catch rates of non-target fish in the longline fisheries for tuna using data from the Observer Programme and commercial fishing returns for the 2002/03, 2003/04 and 2004/05 fishing years. 2. To estimate the quantities of non-target fish caught in the longline fisheries for tuna using data from the Observer Programme and commercial fishing returns for the 2002/03, 2003/04 and 2004/05 fishing years. 3. To estimate the discards of non-target fish in the longline fisheries for tuna using data from the Observer Programme and commercial fishing returns for the 2002/03, 2003/04 and 2004/05 fishing years. 4. To describe trends in the non-target fish catches in the tuna longline fisheries using data from this project and the results of previous similar projects. 5. To compare and contrast the data provided on the revised TLCELR form implemented in 2003 with the Observer data. 1. To review and summarise the historical biological data (including length frequency, sex ratio, age, and reproductive condition data) for swordfish collected by the MFish Observer Programme and other sources since the start of these programmes and evaluate the use of these data as inputs into stock assessments. 2. To update analyses length frequency, sex ratio, and reproductive condition data for swordfish collected by the MFish Observer Programme, shed sampling programmes and other sources up to December To develop standardised CPUE indices for longline caught swordfish and contrast its performance relative to nominal CPUE. 4. To develop a stock assessment, including estimating biomass and sustainable yields for swordfish in the New Zealand EEZ. 1. To update time series of catches, landings, and size composition data collected from a variety of sources up to the 2004/05 fishing year. 2. To estimate CPUE of striped marlin for the recreational fishery. Report for Ministry of Fisheries Project SWO2003/01, Objective 3. Davies, N., Griggs, L. & Unwin, M Information available for developing a stock assessment for New Zealand swordfish (Xiphias gladius). Final Research Report for Ministry of Fisheries Project SWO2003/01, Objective 4. Griggs, L.H., Davies, N.M. (2007). Biological data summaries for swordfish (Xiphias gladius). New Zealand Fisheries Assessment Report 2007/ p. Griggs, L.H., Baird, S.J., Francis, M.P. (2007). Fish bycatch in New Zealand tuna longline fisheries, to New Zealand Fisheries Assessment Report 2007/ p. TUN2005/02: Development of a 1. To develop and implement a shore-based biological catch sampling programme for HMS Medium Term Research Plan

35 commercial catch sampling programme for highly migratory fish species See also TUN2005/01, OBS2005/ /07 STM2006/01: Multi-year stock monitoring of striped marlin including logbook programme implementation swordfish. 2. To describe methods for application of a broad scale shore-based catch sampling programme for all highly migratory fish species. 1. To update time series of catches, landings, and size composition data collected from a variety of sources for the 2005/06 and 2006/07 fishing years. 2. To update CPUE indices for striped marlin for the 2005/06 and 2006/07 fishing years 3. To implement a logbook programme for striped marlin for the recreational fishery for the 2006/07 SAP2006/11: Collection of striped marlin hard parts for ageing 1. Collection of materials for ageing and reproductive biology studies from 50 striped marlin during 2006/07 SAP2006/12: Analysis of SWO tagging data See also TAG , TUN2006/01, TUN2006/02, OBS2006/ /08 STM2007/01: Multi-year stock monitoring of striped marlin including logbook programme implementation 1. Analysis of PSAT tag data from swordfish tagged during 2006/07 to determine horizontal and vertical movement patterns. 1. To update time series of catches, landings, and size composition data collected from recreational sources for the 2007/08 and 2008/09 fishing years. 2. To implement a logbook programme for striped marlin for the recreational fishery for the 2007/08 and 2008/09 fishing years SWO2007/01: Stock assessment of SWO 1. To update the descriptive analysis of the commercial catch and effort data for swordfish from the longline fisheries with the inclusion of data up to the end of the 2006/07 fishing year. 2. To summarise recent biological data (including length frequency, sex ratio, otoliths, and reproductive condition data) for swordfish collected by the MFish Observer Programme, HMS catch sampling programme, swordfish electronic tagging programme, and other sources for use as inputs into the stock assessment. 3. To update the unstandardised and standardised catch per unit effort analyses with the inclusion of data up to the end of the 2006/07 fishing year. See also TUN and TUN2007/02 4. To conduct a stock assessment, including estimating biomass and sustainable yields for the SWO. HMS Medium Term Research Plan

36 PELAGIC FISH TAKEN AS BYCATCH Moonfish (Lampris guttatus) and Ray s bream (Brama brama) The Fisheries This section describes pelagic species, not covered elsewhere, that have been the focus of research. Currently only two species are included, but this section can be expected to increase further over time. Moonfish (Lampris guttatus) and Ray s bream (Brama brama) were introduced into the QMS on 1 October 2004, each under single fishstocks MOO 1 and RBM 1. These bycatch species were added to the Third Schedule of the 1996 Fisheries Act with a TAC set under s14 because they area highly migratory species and it is not possible to estimate MSY for the part of the stocks that are found within New Zealand fisheries waters. Commercial Estimated commercial landings for the fishing year (t), TACs (t), and TACCs (t) for Moonfish and Ray s bream are: MOO 1 RBM 1 FMAs All All TAC TACC yr range Moonfish Most moonfish (70%) is caught as a bycatch of fisheries using surface longlines (7 th most common bycatch species). The main target fisheries catching moonfish by surface longlining HMS Medium Term Research Plan

37 are bigeye tuna (Thunnus obesus) and, to a lesser extent, southern bluefin tuna (T. maccoyii), albacore (T. alalunga) and yellowfin tuna (T. albacares). Mid-water trawling accounts for 18%, bottom trawling 8% and bottom longlining 1%. The main target fisheries using midwater trawling are for southern blue whiting (Micromesistius australis) and hoki (Macruronus novaezelandiae), and bottom trawling for hoki and gemfish (Rexea solandri). Ray s bream At least three closely related species are thought to be caught in New Zealand fisheries. Two species from the genus Brama, Ray s bream (Brama brama) and southern Ray s bream (Brama australis), are difficult to distinguish from external features and have been reported together in both catch statistics and research survey data in unknown ratios. A third closely related species, bronze bream (Xenobrama microlepis), is more easily distinguished from the other two, but is also likely to have been recorded together in catch statistics. Based on records since 2003/04, most (46%) Ray s bream is caught by mid-water trawl. Bottom trawling accounts for 27%, surface longlining 18%, trolling 5%, and bottom longlining 3%. Ray s bream is caught by mid-water trawlers in all FMAs around the South Island, with the largest amounts in mid-water trawls being taken from Stewart-Snares shelf (FMA 5) and the Chatham Rise (FMA 3). The major catches by bottom trawling have occurred on the Chatham Rise (FMA 3). Ray s bream is taken on surface tuna longlines on the east coast of the North Island, especially in the Bay of Plenty-East Cape (FMA 1). Most of the South Island longline catch comes from the west coast in FMAs 5 and 7. It is also taken by tuna trolling, especially on the west coast of the South Island (FMA 7). Recreational An allowance for recreational catch was set for the introduction of Ray s bream into the QMS on 1 October 2004, but no allowance was made for Moonfish. The total recreational allowance for Ray s bream was set at 10t for RBM 1. Recreational fishers take Ray s bream infrequently, generally as bycatch when targeting bluenose, hapuku and bass over deep reefs. The recreational harvest is assumed low, and is likely insignificant in the context of the commercial landings. There is no information on recreational catch levels of moonfish. Moonfish has not been recorded from recreational surveys conducted by MFish. Customary non-commercial An allowance for customary catch was set for the introduction of Ray s bream into the QMS on 1 October 2004, but no allowance was made for moonfish. The total customary allowance was set at 10 tonnes for RBM 1. There is no quantitative information available to allow the estimation of the harvest of Ray s bream or Moonfish by customary fishers, although customary fishers consider moonfish good eating and may have used moonfish in the past. Any harvest is assumed to be insignificant in the context of the commercial landings. Stock Status Moonfish There is no information on the stock structure of moonfish; however, there appear to be distributed throughout the Pacific Ocean. HMS Medium Term Research Plan

38 While moonfish appear to have moderately productive life history characteristics, the stock status is unknown. It is not known if recent New Zealand catch levels are sustainable or whether overall stock removals are sustainable or are at levels that will allow the stock(s) to move towards a size that will support the maximum sustainable yield. Ray s bream Ray s bream probably come from a wide-ranging single stock found throughout the South Pacific Ocean and southern Tasman Sea. The catch of Ray s bream elsewhere in the South Pacific needs to be considered when assessing the status of Ray s bream within the New Zealand s fisheries waters. Total catches in the South Pacific Ocean for the Ray s bream stock range up to tonnes, the majority of which is taken by Chile in the southeast Pacific area (whether this includes one or more species is unknown). The New Zealand contribution (averaging 640 tonnes annually) to total annual removals from the stocks is low (5-10%). It is not known whether overall removals from the stock are sustainable or if they are at levels that will allow the stock to move towards a size that will support the maximum sustainable yield. Research Approach and Information Requirements The stock assessment approaches for other pelagic species are given in Table 20. The proposed levels of observer coverage and information to be collected by observers in relation to other pelagic species are given in Table 21. A chronology of related research undertaken since 1997/1998 is given in Annex 11. Table 20: Other pelagic fish taken as bycatch - current use of information and stock assessment approaches Species Moonfish Ray s bream Other species Assessing stock status Monitor landings and catch sampling Monitor landings Information available Catch and biological parameters Catch and biological parameters Stock assessment current n/a n/a Stock assessment future Unlikely, but an assessment of the wider stocks maybe undertaken in international settings. Unlikely, but an assessment of the wider stocks maybe undertaken in international settings. Monitor landings Catch n/a Unlikely, but assessments of the wider stocks maybe undertaken in international settings. Research needs Stock structure, relative abundance indices Species composition, stock structure, and relative abundance indices Biological parameters, stock structure and relative abundance indices Table 21: Other pelagic fish observer coverage Species Proportion of fishery to be covered Reason for coverage Information to be collected Moonfish Longline no specific days, but catch sampling to be linked to the 733 days of target tuna longline coverage. To estimate catches and obtain biological samples Catch and effort, size composition of catch, and biological samples. Ray s bream Longline no specific days, but catch sampling to be linked to the 733 days of target tuna longline coverage and the 50 days of albacore troll coverage and elsewhere as possible especially in midwater trawl fisheries. To estimate catches and obtain biological samples, including whole specimen taken in various fisheries and research surveys Catch and effort, size composition of catch, and biological samples. HMS Medium Term Research Plan

39 Other species Coverage in purse-seine, longline, and midwater trawl fisheries Implications for Research Sustainability Little is known about these species with even estimates of stock-wide catches and abundance indices not available. In the absence of such information, the best approach is to undertake studies of the biological characters of these species to determine their productivity and possible vulnerability to exploitation. In instances where bycatch species are shown to be potentially vulnerable to exploitation further research, including collaboration with international researchers may be required. Effects of Fishing The New Zealand tuna longline fisheries often catch non-targeted species. Data from the Ministry of Fisheries Observer Programme are used to quantify the extent of fish bycatch caught on tuna longlines in New Zealand waters. The species most commonly recorded by observers are blue shark (Prionace glauca), albacore tuna, and Ray s bream (Brama brama). Catches of oilfish, moonfish, and rudderfish have all increased recently. Tuna longline fishers (primarily domestic vessels) in northern waters also catch striped marlin but these are not retained. Both catch per unit effort and total estimated catch of this species show a great deal of inter-annual variability: there are no consistent trends. The CCSBT established an Ecologically Related Species Working Group (ERS-WG) to consider the impact of SBT fisheries on other species and the impacts of other species on SBT. Critical work from the ERS-WG has included work on mitigation of sea bird catches and considerable education materials for sea birds and sharks. Research has also been considered on trophic interactions that include SBT. Medium Term Research Plan for other pelagic fish species taken as bycatch Bold = research to be proposed for 2009/2010 Italic = multi-year research programme Species 2008/ / /11 Regular Moonfish Ray s bream Other species Full Full Species Identification Full Full of tuna fisheries (4-5 years) (annually) Species 2004/ / / /2008 Moonfish HMS Medium Term Research Plan

40 Ray s bream Other species logbooks and observers logbooks and observers logbooks and observers Species 2000/ / / /2004 Moonfish logbooks and observers logbooks and observers Age & growth, maturity and natural mortality Age & growth, maturity and natural mortality Ray s bream logbooks and observers logbooks and observers Age & growth, maturity and natural mortality Age & growth, maturity and natural mortality Other species logbooks and observers logbooks and observers logbooks and observers logbooks and observers Annex 11: Chronology of research of other pelagic species taken as bycatch Year Project Objectives Reports 2003/04 TUN2003/01: Productivity of Important Non-target Species Caught in the Tuna Longline Fishery 2004/05 See also TUN2004/01, OBS2004/ /06 See also TUN2005/02, PEL2005/01, OBS2005/ /07 See also TUN2006/02. PEL2006/02, OBS2006/ /08 See also TUN2007/01 1. To determine the growth rate, age at maturity, longevity and natural mortality rate of moonfish (Lampris guttatus). 2. To determine the growth rate, age at maturity, longevity and natural mortality rate of Ray s bream (Brama brama). 3. To determine the growth rate, age at maturity, longevity and natural mortality rate of swordfish (Xiphias gladius). Paul, L.J.; Francis, M.P.; Ó Maolagáin, C. (2004). Growth rate, age at maturity, longevity and natural mortality rate of Ray s bream (Brama sp.). Final Research Report of Project TUN2003/01. Francis, M.P.; Griggs, L., and Ó Maolagáin, C. (2004). Growth rate, age at maturity, longevity and natural mortality rate of moonfish (Lampris guttatus). Final Research Report of Project TUN2003/01. HMS Medium Term Research Plan

41 GAMEFISH TAG RECAPTURE PROGRAMME Striped marlin (Tetrapturus audax), mako shark (Isurus oxyrinchus), blue shark (Prionace glauca), kingfish (Seriola lalandi) & yellowfin tuna (Thunnus albacares) The Programme This gamefish tagging programme is a cooperative project between the Ministry of Fisheries, who contract a research provider for database management and reporting, the New Zealand Big Game Fishing Council that organise the purchase and distribution of tags, fishing clubs and anglers who catch and tag most of the fish and return release details, and commercial fishers in New Zealand and the wider southwest Pacific who report about half of all recaptures. It is intended to get observers to deploy tags opportunistically in future years. Information Gathered on Stocks In many countries large HMS species are tagged in cooperative programmes as it provides the opportunity to opportunistically gather information that is difficult to collect using other means. Tag data provides a description of the size and distribution of fish released by recreational fishers. Recaptures provide information on movement, stock structure, handling mortality, time at liberty, displacement rates, and in some circumstances growth rates of the species involved. Wide-spread tagging and a large number of recaptures may help fisheries managers define stock structure or sub-stock boundaries which may be used in modelling movement between regions and in fisheries management. Research Approach and Information Requirements HMS Medium Term Research Plan