3 Deep-water siki sharks in the Northeast Atlantic (IV XIV)

Transcription

1 ICES WGEF REPORT 2009ICES WGEF REPORT Deep-water siki sharks in the Northeast Atlantic (IV XIV) 3.1 Stock distribution A number of species of deep water sharks are exploited in the ICES area. This section deals with Centrophorus squamosus and Centroscymnus coelolepis, which have been the two species of greatest importance to commercial fisheries. For the purposes of this section, the term siki is used to describe the combination of leafscale gulper shark and Portuguese dogfish. Although these species have very different biological traits, it has been necessary for ICES to combine them for assessment purposes. This is because landings data for both species were combined for some of the main countries for most of the time since the beginning of the fishery. The term siki as used here does not have the same meaning as in French commercial fisheries, where it encompasses all commercially exploited deep water sharks. Leafscale gulper shark (Centrophorus squamosus) has a wide distribution in the NE Atlantic from Iceland and Atlantic slopes south to Senegal, Madeira and the Canary Islands. On the Mid Atlantic Ridge it is distributed from Iceland to the Azores (Hareide and Garnes, 2001) The species can live as a demersal shark on the continental slopes (depths between m) or have a more pelagic behaviour, occurring in the upper 1250 m of oceanic water in areas with depths around 4000 m (Compagno and Niem, 1998). Available evidence suggests that this species is highly migratory (Clarke et al., 2001; 2002). Recent information revealed that in contrast to other NE Atlantic areas, where males are predominant, the sex ratio at the Faroes was approximately 1:1 (Vinnichenko and Fomin, 2009 WD). Available information reveals that pregnant females and pups are found in Portugal, both the mainland (Moura et al., 2006 WD) and Madeira, whereas pre pregnant and spent females are found in the northern areas (Clarke et al., 2001; 2002; Garnes, pers. comm.) and in the Faroes (Vinnichenko and Fomin, 2009, WD). In the absence of more clear information on stock identity, a single assessment unit of the Northeast Atlantic has been adopted. Portuguese dogfish (Centroscymnus coelolepis) is widely distributed in the NE Atlantic. Stock structure and dynamics are poorly understood. Specimens below 70 cm have been recorded very rarely in the NE Atlantic. There is a lack of knowledge of migrations, though it is known that females move to shallower waters for parturition and vertical migration seems to occur (Clarke et al., 2001). The same size range and maturity stages exist in both the northern and southern ICES continental slopes. This information may suggest that, contrary to leafscale gulper shark, this species is not so highly migratory, though it is widely distributed. Preliminary genetic work (Moura et al., 2008 WD) did not reject the null hypothesis that there was no significant difference between the northern and southern areas. In the absence of more clear information on stock identity, a single assessment unit of the Northeast Atlantic has been adopted. This does not consider that the biology and available information on distribution of these two species is different. However in the absence of better data, it is the best approach possible. Further genetic and other studies are still required on both species.

2 50 ICES WGEF REPORT 2009ICES WGEF REPORT The fishery History of the fishery No new information was available in Fisheries taking these species were described extensively in ICES STECF, 2006 presented a review of available information on deep water shark gillnet fisheries. After the ban on gillnet fisheries in the northern area, gillnet and longline fisheries developed in Subarea VIII and Division IXb in Analyses of the French fishery were available from industry science partnerships (Biseau, 2008b WD). This document demonstrates that there has been only a little change in the mean depth fished by the deep water French fleet since 2000, but that new areas have been fished in this period. Biseau, 2008a WD revealed that there has been a slight tendency for catches of deepwater sharks to come from shallower depths, in the period This possibly reflected the change in fishing pattern The fishery in 2008 C. squamosus and C. coelolepis are both taken in several mixed trawl fisheries and mixed longline fisheries. They are taken as a bycatch in other fisheries, for example the anglerfish gillnet fishery. There was a directed Spanish (Basque country) longline fishery in Subarea VIII from , this stopped in 2006 (although bycatch was still taken), re started in 2007 and ceased in Information on deep water shark bycatches made by Russian vessels operating in 2008 in other areas (Vinnichenko and Fomin, 2009 WD) is summarized below ICES advice applicable In 2008, given the very poor state of Portuguese dogfish and leafscale gulper shark, ICES recommended a zero catch. This recommendation was based on cpue information available. Portuguese dogfish and leafscale gulper shark were considered depleted despite the fact that the rates of exploitation and stock sizes of deep water sharks could not be quantified. In 2006, ICES noted substantial declines in cpue series for both C. coelolepis and C. squamosus in Subareas VI, VII and XII, suggesting that the stocks of both species were depleted. Cpue for both species in the northern area (VI, VII and XII) had displayed strong downward trends leading to the conclusion that the stocks were being exploited at unsustainable levels. In Division IXa, cpue series, although short, appeared to be stable. In 2006, ICES advised that no target fisheries should be permitted unless there were reliable estimates of current exploitation rates and stock productivity. ICES advised that the TAC should set at zero for the entire distribution area of the stocks and additional measures should be taken to prevent by catch of Portuguese dogfish and leafscale gulper shark in fisheries targeting other species Management applicable The TAC adopted for deep sea sharks in Community waters and international waters at different ICES subareas are summarized in the table below. The

3 ICES WGEF REPORT 2009ICES WGEF REPORT deep sea shark category includes the following species: Portuguese dogfish, leafscale gulper shark, birdbeak dogfish (Deania calceus), kitefin shark (Dalatias licha), greater lantern shark (Etmopterus princeps), velvet belly (Etmopterus spinax), black dogfish (Centroscyllium fabricii), gulper shark (Centrophorus granulosus), blackmouth dogfish (Galeus melastomus), mouse catshark (Galeus murinus), and Iceland catshark (Apristurus spp).

4 52 ICES WGEF REPORT 2009ICES WGEF REPORT 2009 FISHING OPPORTUNITIES V, VI, VII, VIII, IX X XII (INCLUDES ALSO DEANIA HISTRICOSA AND DEANIA PROFONDORUM 2005 and (1) (1) (1) 10 (1) 25 (1) (2) 0 (2) 0 (2) (1) Bycatches only. No directed fisheries for deep sea sharks are permitted. (2) Bycatches of up to 10 % of 2009 quotas are permitted. 3.3 Catch data A number of effort regulations also apply to these deep water shark species. Council of the EU Regulation (EC) No 2347/2002 sets maximum capacity and power (kw) ceilings on individual member states fleets fishing for deepwater species. Council Regulation (EC) No 27/2005 sets a limit of effort (kilowatt*days) at 90% the 2003 level for 2005, and in at 80% for Council Regulation (EC) No 1568/2005 bans the use of trawls and gillnets in waters deeper than 200 m in the Azores, Madeira and Canary Island areas. Council Regulation (EC) No 41/2007 banned the use of gillnets by Community vessels at depths greater than 600 m in ICES Divisions VIa, b, VII b, c, j, k and Subarea XII. A maximum bycatch of deep water shark of 5% is allowed in hake and monkfish gillnet catches. This ban does not cover Subareas VIII or IX. In 2006, the ban on gillnetting applied to waters deeper than 200 m, but this was revised to 600 m, in 2007, following advice from STECF. Council Regulation (EC) No 881/2008 prohibited fishing for deep sea sharks in Community waters and waters not under the sovereignty or jurisdiction of third countries of V, VI, VII, VIII and IX by vessels flying the flag of Portugal. A gillnet ban in waters deeper than 200 m is also in operation in the NEAFC regulatory Area (all international waters of the ICES Area). NEAFC also ordered the removal of all such nets from these waters by the 1st February Landings Figure 3.1 shows landings trends by country, and Figure 3.2 shows trends by area. The Working Group estimates of total landings of mixed deep water sharks, believed to be mainly Portuguese dogfish and leafscale gulper shark but possibly also containing a small component of other species, are presented in Tables In 2006, WGEF produced estimates of landings of each of these species (ICES, 2006). This has not been updated since. In 2008 France presented a split of French landings, by species (Biseau, WD 2008a), but the ratios were not used by WGEF because they were derived from 1990s data on species abundance by depth which is no longer valid, as a consequence of the declining relative abundance of Portuguese dogfish. It can be seen that landings have declined from around t from 2001 to 2004, to about 1400 t in 2008 (Figures 3.1 and 3.2). Recent (2008) landings are the lowest since the fishery reached full development in the early 1990s and

5 ICES WGEF REPORT 2009ICES WGEF REPORT is slightly lower than TACs available (1715 t), although the TAC does include other deep water shark species. Information on deep water shark bycatches made by Russian vessels operating in 2008 in various areas is summarized in Table Discarding No new information on discarding was made available at the 2009 meeting, however it is expected that discarding has increased, as a consequence of management regulations (e.g. bycatch limits; quota may be limited for some fleets) Quality of the catch data Historically, very few MS presented landing data disaggregated by species. Portugal has supplied species specific data for many years. In recent years other MS have increased species specific reporting of landings but some of these data may contain misidentifications. There are no reliable estimates of levels of misreporting of these species but it is believed to be a minor problem. Immediately prior to the introduction of quotas for deep water species in 2001, it is believed that some vessels may have logged deep water sharks as other species (and vice versa) in an effort to build up track record for other deep water species (or deep water sharks). It is also likely that, before the introduction of quotas for deep water sharks, some gillnetters may have logged monkfish as sharks. Since the introduction of quotas on deep water sharks in 2005, it is likely that some underreporting has occurred. However, the introduction of legislation on buyers and sellers registration in the UK and Ireland in 2006 may mean that the reported landings for 2006 onwards are more reliable. IUU fishing is also known to take place, especially in international waters. 3.4 Commercial catch composition Species composition No new information is available on composition of generic landings. In 2005, WGEF split all generic elasmobranch nei landings from the Northeast Atlantic in the period (Figueiredo et al., WD 2005). In 2006 WGEF siki landings were split by species using data available of species proportion by MS, fishery and ICES subarea. When such data were not available for a particular MS the proportion estimated to a similar fishery/subarea was adopted. Although many assumptions were made in order to reconstruct landings, the WGEF considered that they represented the best estimates of recent and historic catches of these species that can be produced Length composition Length frequency information was provided for 2007 from the Portuguese fishery (Moura and Figueiredo, 2008 WD) Quality of catch and biological data WGEF finds it difficult to quantify landings data when MS report data for both live weight and for livers. This potentially can lead to duplication of

6 54 ICES WGEF REPORT 2009ICES WGEF REPORT 2009 data and overestimation of landings. WGEF asks all MS to explain how landings of livers are raised to total live weight, and to report if duplication could be happening. Those nations undertaking scientific fisheries for deep water species can take large quantities of fish (e.g. deep water sharks) and should ensure that these catches are reported accordingly. 3.5 Commercial catch-effort data In 2006, WGEF summarized all the available cpue series. In 2008, standardized lpue from Portuguese longliners data were presented (Figueriedo et al., 2008 WD). 3.6 Fishery-independent surveys In 2009 the deep water survey undertaken by Scotland took place. These surveys are being conducted by Marine Scotland in Division VIa at depths ranging from m since However since 1998 the survey has been reasonably consistent about survey design, gear deployed and area covered (Jones et al., 2005). The survey uses a large commercial trawl (made by Jackson) and is towed for a period of hours at speeds of knots. Initially, the survey was carried out on a biennial basis, but since 2004 has been carried out annually. Ireland carries out a deep water survey each year in Area VI and VII, concentrating on NW Ireland west of Scotland, and the Porcupine area to the west of Ireland. Fishing takes place at 500 m, 1000 m, 1500 m and 1800 m. Parallel tows are carried out in the northernmost area with Scotland for intercalibration purposes. The survey took place in September from The next survey will occur in December After this the survey will become biennial, beginning in Several shark species are sampled during these surveys. Analysis distribution and life history parameters of Centrophorous squamosus and Centroscymnus coelolepis will be presented at the 2010 WGEF meeting. These and other surveys are part of a planned coordinated survey in the ICES area, through the Planning Group on North East Atlantic Continental Slope Surveys (PGNEACS). 3.7 Life-history information 3.8 Assessments No new information since No new assessments were conducted in Quality of assessments 3.10 Reference points No new assessments were conducted in Ulim is set at 0.2* virgin biomass and Upa is set at 0.5* virgin biomass (ICES, 1998). This is in common with other deep water stocks. However abundance indices do not always correspond to the start of the fishery.

7 ICES WGEF REPORT 2009ICES WGEF REPORT Management considerations 3.12 References On the basis of their life history parameters, being slow growing and late maturing, these two species are considered highly vulnerable to exploitation. There is no new information (from 2008), to alter our perception of the status of these stocks, which are considered depleted. The ban on gillnetting in VI and VII has led to some diversion of effort to IVa, VIII and IX and also to West Africa. WGEF expresses concern that new fisheries are developing in new areas without prior evaluation of sustainable catches having been carried out. IUU fishing is known to take place in international waters, and this may be continuing. Further studies of biology and stock discrimination are still required, as fishing on these species expands to new areas. Biseau, A. 2008a WD. French Fishing Industry Science partnership. Preliminary analysis of the French industry database on the deep sea fishery. WD to ICES WGDEEP. Biseau, A. 2008b WD. French landings of deep water sikis sharks by species. WD to ICES WGEF. Clarke, M.W., Connolly, P.L. and Bracken, J.J Aspects of reproduction of deep water sharks Centroscymnus coelolepis and Centrophorus squamosus from west of Ireland and Scotland. Journal of the Marine Biological Association of the United Kingdom, 81: Clarke, M.W., Connolly, P.L. and Bracken, J.J Age estimation of the exploited deep water shark Centrophorus squamosus from the continental slopes of the Rockall Trough and Porcupine Bank. Journal of Fish Biology, 60: Compagno, L. J. V. and Niem, V. H Squalidae. In FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 2. Cephalopods, crustaceans, holothurians and sharks, pp Ed. by K.E. Carpenter and V.H. Niem. FAO, Rome. Figueiredo I., Bordalo Machado, P., Gordo, L.S., and Moura, T WD. An overview of elasmobranch NEI landings from the north east Atlantic in the period Working Document to WGEF. Figueiredo, I., Moura, T. and Bordalo Machado, P WD. Revision and update of landing per unit effort data of deep water sharks Portuguese dogfish and leafscale gulper shark in Portuguese longline fishery ( ). Working Document to WGEF. Hareide, N. R. and Garnes, G The distribution and catch rates of deep water fish along the Mid Atlantic Ridge from 43 to 61 N. Fisheries Research, 519: ICES Report of the Working Group on Elasmobranch Fishes (WGEF), June 2006, ICES Headquarters. ICES CM 2006/ACFM: pp. Jones, E., Beare, D., Dobby, H., Trinkler, N., Burns, F., Peach, K. and Blasdale, T The potential impact of fishing activity on the ecology of deep water chondrichthyans from the west of Scotland. ICES CM 2005/N:16. Moura, T.,Figueiredo, I., Neves, A., Farias, I., Pereira, B. S. and Gordo, L WD. Reproductive data on Portuguese dogfish Centroscymnus coelolepis, Leafscale gulper shark Centrophorus squamosus and gulper shark Centrophorus granulosus commercially exploited in the Portuguese continental slope. Working Document.

8 56 ICES WGEF REPORT 2009ICES WGEF REPORT 2009 Moura, T., Figueiredo, I. and Gordo, L WD. Analysis of genetic structure of the Portuguese dogfish Centroscymnus coelolepis caught in the Northeast Atlantic using mitochondrial DNA (Control Region) Preliminary results. WD to WGEF. Moura, T., and Figueiredo, I., 2008 WD. Portuguese dogfish and leafscale gulper shark from the Portuguese longline fishery. Working Document to WGEF. STECF, Report of the STECF Working Group on deep sea gillnet fisheries. Commission Staff Working Paper. 52 pp. Vinnichenko, V.I WD. Russian deep sea investigations and fisheries in the Northeast Atlantic in Working Document to ICES Working Group on the Biology and Assessment of Deep Sea Fisheries Resources (Copenhagen, Denmark, 3 10 March 2008). Vinnichenko, V.I. and Fomin K.Yu WD. Russian research and fisheries of sharks and skates in the Northeast Atlantic in Working document presented to ICES WGEF 12 pp.

9 ICES WGEF REPORT 2009ICES WGEF REPORT Table 3.1. Deep water siki sharks in the Northeast Atlantic. Working Group estimate of combined landings of Portuguese dogfish and leafscale gulper shark (t) by ICES area IV a Va Vb VI VII VIII IX X XII XIV Unknown Area

10 58 ICES WGEF REPORT 2009 Table 3.2. Deep water siki sharks in the Northeast Atlantic. Working Group estimate of combined landings of Portuguese dogfish and leafscale gulper shark (t) by country France UK (Scotland) UK (England and Wales) Ireland Iceland Spain (Basque C) Portugal Germany Estonia Latvia Lithuania Poland Russia Spain (Galicia) Faeroe Island Norway Total

11 ICES WGEF REPORT Table 3.3. Deep water siki sharks in the Northeast Atlantic. Deep water shark bycatches made by Russian vessels operating in 2008 in ICES Divisions I, V, VI and XII (Vinnichenko and Fomin, 2009 WD). I ICES DATE FISHING GEAR FISHING EFFORT Barents Sea Vb southern part of the Faroes VIb1 Rockall Bank VIb1 Rockall Bank July/August 2008 March, Sept and Nov 2008 Trawl and Longline 1 3 longliners class tonnage 8 Longline Longline Total: 99 fishing day hook Total: 96 fishing days hooks Total: 3 fishing days DEEP- FISHING WATER DEPTH SHARKS 1 t m t m 92.7 t m 20.4 t XIIc July August Bottom trawl 2.9 t Mid Atlantic Ridge Nov Dec 2008

12 60 ICES WGEF REPORT Norway Faroe Island Spain (Gallicia) Poland Lithuania Latvia Estonia Germany Portugal Spain (Basque C) Iceland Ireland UK (England and Wales) UK (Scotland) France Figure 3.1. Deep water siki sharks in the Northeast Atlantic. Working Group estimates of landings, by country. XIV XII X Landings by sub-division IX VIII VII VI Vb Va IV a Figure 3.2. Deepwater siki sharks in the Northeast Atlantic. Working Group estimates of landings, by ICES Subarea.