SKJ Skipjack BET Bigeye tuna YFT Yellowfin tuna SCRS 2014

Transcription

1 SKJ Skipjack BET Bigeye tuna YFT Yellowfin tuna SCRS 2014

2 SCRS 2014 SKJ Skipjack (assessed in 2014) BET Bigeye tuna (assessed in 2010) YFT Yellowfin tuna (assessed in 2011) Responses to COM Requests Research and Statistics: Recommendations & Work Plan [SCI-032] Report of the 2014 ICCAT East and West Atlantic skipjack stock assessment meeting. 2

3 SCRS 2014 Assessment of SKJ stocks. Update of recent and some historical catches Reporting of PS catch on free schools and FADs Update of CPUE indices and other fishery indicators Development of a tropical tuna tagging program to support assessment of stock status Development of on-board automated monitoring of PS catches Next assessments planned: [BET 2015] [YFT-2016] 3

4 SCRS

5 A multi-specific fishery Tropical tuna, a multi-gear and a multi-specific fishery SKJ BET YFT 20,000 t Purse seine Longline Baitboat Others Task II data Multi-specific fisheries nature of the Tropical Tuna (TT) fisheries. TT species are strongly associated in the pelagic ecosystem. 5

6 A multi-specific fishery Tropical tuna, a multi-gear and a multi-specific fishery Historic high of the world production in 2012: 4.6 million tonnes of tropical tunas 2.8 million tonnes of SKJ Atlantic Tropical Tuna represents 9% of the world production (380,000 t - average ). 6

7 A multi-specific fishery Tropical tuna, a multi-gear and a multi-specific fishery % average catch in TT catches in the Atlantic were in general decline since the historic peak in 1994 (487,000 t). The tendency changed since SKJ historic high in 2012 (258,000 t) 7

8 A multi-specific fishery Tropical tuna, a multi-gear and a multi-specific fishery % average catch in % of the Atlantic TT are caught by surface gears: (333,000 t - average ). The use of Fish Aggregation Devices (FADs) causes concerns for management. 8

9 A multi-specific fishery Tropical tuna, a multi-gear and a multi-specific fishery 377,300 t in

10 A multi-specific fishery Impact of increasing use of FADs Change in the species composition of free schools. Free schools of mixed species were considerably more common prior to the introduction of FADs. The association with FADs may also have an impact on: the biology (growth rate, plumpness of the fish) and the ecology (distances, movement, orientation) [ ecological trap ] 10

11 A multi-specific fishery Recent changes in the spatial distribution of the EU PS fishery SKJ catches by EU PS SKJ catches by EU PS Latitudinal expansion and westward extension of the fishing area since the early 1990s SKJ catches made by EU PS, vs showing the withdrawal from the Senegal zone (an area of free school fishing) due to non-renewal of fishing agreements. The proportion of SKJ catches on FADs has continued to increase, reaching slightly more than 90% of the catches 11

12 A multi-specific fishery Fishing effort of EU and associated purse seiners Difficult to estimate a fishing effort targeting TT as well as fishing effort on FADs. Nominal PS has decreased regularly since the mid-1990s up to Recent considerable increase: EU PS have transferred their effort (newer vessels with greater fishing power and carrying capacities ) to the East Atlantic (piracy - Indian Ocean) Presence of one new PS fleet operating from Tema (Ghana) Number of PS seems to have remained steady since

13 A multi-specific fishery Review of PS & BB Catches from the Ghanaian fleet New estimates of Task I and Task II catch and effort and size for these fleets for the period Estimates for the period are provisional [compared with previous estimates]: BET & YFT catches were significantly lower [yearly average of 2,500 t (BET) and 4,300 (YFT) ] over the period SKJ catches were significantly higher [yearly average around 9,000 t] : SKJ catches reported were underestimated by around 28%, which gives an average of 12,000 t/year Estimates for are under review and are considered provisional SKJ 13

14 A multi-specific fishery Estimate of the small tropical tuna landed as faux-poisson in the local market of Abidjan in Côte d Ivoire Around 6,600 t/year [ , EU and associated PS]. Around 10,500 t/year [ , all PS in the eastern Atlantic] SKJ represents around 30% of the total faux-poisson. The Committee regularly integrates these estimates in the reported historical catches for the EU-purse seiners since 1982, as well as in the catch-at-size matrix. 14

15 A multi-specific fishery Uncertainty on biological parameters There is a high degree of uncertainty on biological parameters needed to conduct accurate stock assessments: Stock structure and movements. Growth (VB vs two-stanza); differences by sex Natural mortality 15

16 A multi-specific fishery Atlantic tropical tagging program [AOTTP] A multi-species, multi-annual, large-scale tropical tuna tagging program is needed. Never done in the Atlantic: SKJ: , YFT: , BET: ) Successful large programs in Pacific and Indian Ocean => data integrated in SA Importance of simultaneously tag the 3 main species (YFT, SKJ, BET) as well as smalltunas: Comparative biological results (growth, natural and fishing mortality at age) Indication of movements and possible stock structure Analysis of interactions among fleets Effect of FADs on tuna resources Evaluation of management measures (e.g. impact of closures) Tagging program, if successful, provide data useful to answer and reduce uncertainty of the most important question: What is the current population size? Tropical Tuna Tagging in the 4 trfmos IO AO WCPO YFT SKJ BET EPO 0 200, , , ,000 1,000,000 16

17 A multi-specific fishery Atlantic tropical tagging program [AOTTP] The SCRS reiterates the importance of the implementation of a large-scale tagging program for tropical tuna species (AOTTP) to improve Stock Status determination. EU has expressed interest in funding 80% of AOTTP budget!!! CONDITIONAL of the co-funding of remaining 20% by other CPCs or other sources [ in kind : no more than half of the co-funding] This is a unique opportunity! Year Total Total (x1,000 ) 6,401 5,425 2, ,171 16,876 Total Total (x1,000 ) 16,876 EU funding 13,500 Co-Funding total 3, /year Cash 1, /year In kind 1, /year Examples of possible co-funded activities: Specific projects within AOTTP implemented by ICCAT: tagging in specific areas (e.g. central, western AO) tagging specific species (e.g. neritic tunas) Provision of pole-and-line vessel(s) time Provision of tags and equipment 17

18 A multi-specific fishery Atlantic tropical tagging program [AOTTP] AOTTP is a program of ICCAT and COOPERATION will be needed from ALL CPCs to facilitate operations: Funding Free/Research access to coastal countries EEZ to tag tunas Free/Research access to coastal countries territorial waters to fish for bait (pole-andline vessels as tagging platforms) Cooperation of local institutions for recoveries activities Access to logbook data to retrieve date/position of recoveries (in particular for purseseine fleet, need to link well to fishing set): confidentiality of data to be ensured Capacity building activities: training of scientists from coastal developing countries in tagging techniques, tagging/recovery data collection, tagging data analysis, etc Need to start taking those steps ahead of the start of the AOTTP not to delay operations when funding is granted 18

19 SKJ Assessed in

20 SKJ Skipjack, Listado, Listao Scientific name Distribution Spawning grounds Maturity Katsuwonus pelamis Gregarious species that is found in tropical, subtropical, and warm temperate waters Breed opportunistically throughout the year over wide areas of the Atlantic Depending on the areas, between 42 and 50 cm Life span Around 5 years Maximum size Around 100 cm (18 kg) Natural mortality M vector decreasing with size (Gaertner, 2014) management units 20 20

21 SKJ % average catch in Atlantic SKJ, although the largest volume production of Atlantic tunas (i.e., 258,300t in 2012), represents a small proportion of the world-wide production of this species Atlantic SKJ represents 7% of the world production (average ). 21

22 SKJ Purse seine Longline Baitboat Others 10,000 t 22

23 SKJ 5,000 t Purse seine Longline Baitboat Others 23

24 SKJ SKJ Catches by main CPC and gear type t in t in t in

25 SKJ Estimated 2013 SKJ catches in the East Atlantic amounted to 203,500 t, that is, an increase of around 54% compared to the average of A strong increase in the skipjack catches by European purse seiners is noted, probably due to the high selling price of this species. High SKJ catches by PS off Mauritania, beyond 15 o N latitude, in 2012 between August and November. 25

26 SKJ-E SKJ Catches (East) by main CPC and gear type in ,500 t in

27 SKJ-W SKJ Catches (West) by main CPC and gear type in ,000 t in

28 SKJ SCRS catalogue on SKJ statistics (Task I and Task II) 28

29 SKJ SKJ Fishery indicators Mean weight After a continuous decrease over time, mean weight increases in recent years for PS and BB. Trend reversed since 2012 (together with a broadening of the range of sizes caught). Mean weight increases only for PS (VEN), stable for BB (BRA) 29

30 SKJ-E SKJ (East) Fishery indicators Nominal fishing effort Nominal carrying capacity [PS-BB] Number of PS Total surface fished Number of 5 squares fished yearly in the entire Atlantic by all fleets (CATDIS file) with a yearly SKJ catch >10 t. 30

31 SKJ-E SKJ (East) Fishery indicators Prices for SKJ and YFT Yearly catch per purse seiner (EU and associated) Price (USD/ton) Year SKJ YFT Number of successful sets by fishing mode 31

32 SKJ-E SKJ (East) Fishery indicators Trends in CPUE Fleets CPUE time series BB_POR BB_CAN BB_DAK PS_EC Free/FADs PS_EC Free [Q inc = 3% y -1 ] 32

33 SKJ-W SKJ (West) Fishery indicators Trends in CPUE Fleets CPUE time series Larval index LL_USA LL_USA PS_VEN [Q inc = 1% y -1 ] BB_BRA

34 SKJ - E Stock status (East Atlantic) Traditional stock assessment models are difficult to apply to skipjack Catch-only model ASPIC Bayesian Surplus Production (BSP) model Mean length-based mortality estimator No estimate of MSY Catch only model suggests that recent catches could be close to MSY No evidence however (e.g., decrease in CPUE or in mean weight) that Eastern SKJ be overfished Model type MSY Catch only model (Schaefer)? ASPIC (Schaefer)? BSP (Schaefer)? Current Catch (2013) 203,500 t Average catches (5 years) 174,600 t 34

35 SKJ - W Stock status (West Atlantic) Model type Catch only model (Schaefer) ASPIC (Schaefer) MSY 29,0 31,000 t 29,9 32,630 t BSP (Schaefer)? MSY: 30,000 32,000 t Current Catch (2013) Average catches (5 years) 18,000 t 27,200 t ASPIC: B2013 / BMSY = 1.28 ( ) F2013 / FMSY = 0.69 ( ) 35

36 SKJ There is currently no specific regulation in effect for skipjack tuna. Several time/area regulatory measures on banning fishing on FADs [Rec ] and [Rec ] or on complete closure to surface fleets [Rec ] have however been implemented in the East Atlantic but the intended aim was to protect YFT and BET juveniles. [Rec ] established a moratorium on FAD fishing in the area that extends from the African coast to 10ºS and 5ºW -5ºE during Jan-Feb [into force in 2013]. Due to the shift by the EU fleet outside the regulated area and the decrease in activity of the Ghanaian PS during the moratorium period, a slight fall in catches of BET juveniles has been observed but no significant change for SKJ and YFT. 36

37 SKJ Despite the absence of evidence that the eastern stock is overexploited, but considering 1. the lack of quantitative findings for the eastern stock assessment, 2. pending the submission of additional data (FADs and Tagging Program), the Committee recommends that the catch and effort levels do not exceed the level of catch in recent years. Increasing harvests and fishing effort for SKJ could lead to involuntary consequences for other species that are caught in combination with SKJ in certain fisheries. For the West Atlantic, the Committee has not formulated any management recommendation, and has only indicated that the catches should not be allowed to exceed the MSY. 37

38 BET Last assessment:

39 BET Bigeye tuna, Patudo, Thon obèse Scientific name Distribution Spawning grounds Maturity Life span Thunnus obesus Widely distributed in the tropical and subtropical waters of the Atlantic. Geographical limits are 55º-60ºN and 45º-50ºS. Spawning takes place throughout the entire year in a vast zone in the vicinity of the equator with temperatures above 24ºC from the coast of Brazil to the Gulf of Guinea. primer trimestre en mayoria y zona limitada entre 5 S y 10 S Around cm - 3 year old Around 15 years management unit Maximum size Around 200 cm Natural mortality Assumed to be 0.8 for ages 0 and 1, and 0.4 for ages 2+ 39

40 BET % average catch in Atlantic bigeye tuna represents around 18% of the world production (average ). It represents the lowest volume production of Atlantic tropical tunas at about 75,600t per year (average ). 40

41 BET Purse seine Longline Baitboat Others 5,000 t 41

42 BET 4,000 t Purse seine Longline Baitboat Others 42

43 BET BET Catches by main gear type 63,066 t in 2013 % average catch in Historic high of about 133,000 t in After 1994, all major fisheries exhibited a decline of catch; related to declines in fishing fleet size (LL) as well as decline in CPUE (LL & BB). The number of active PS declined by more than half from 1994 until 2006; but then increased since

44 BET BET Catches by main CPC and gear type in ,066 t in

45 BET Average weight of bigeye tuna by fishing gear Average fish weight differs between major gears Bigeye tuna caught free schools are significantly larger than those caught on FADs; these differences are notably large in the last four years 45

46 BET Stock status MSY = 92,000 t (78, ,600 t) 2013 Yield = 63,066 t B 2009 /B MSY = 1.01 ( ) F 2009 /F MSY = 0.95 ( ) There is considerable uncertainty in the assessment of stock status and productivity for bigeye tuna. 52% of the outcomes indicate the stock is consistent with the Convention Objective. 46

47 BET Outlook t in 2013 TAC ,000 54% 63% 71% 75% 79% 82% 84% 85% 86% 87% 70,000 54% 61% 67% 71% 74% 76% 77% 79% 80% 81% Current TAC 85,000 t 80,000 54% 58% 62% 66% 68% 70% 71% 72% 73% 74% 90,000 54% 57% 58% 60% 61% 62% 62% 63% 63% 64% 100,000 53% 54% 54% 54% 54% 54% 54% 54% 55% 55% 110,000 45% 45% 45% 45% 45% 45% 45% 45% 45% 45% Modeled probabilities of the stock being maintained at levels consistent with the Convention Objective over the next five years are about 60% for a future constant catch of 85,000 t. Reported catches for 2013 (63,066 t) are lower than the corresponding TAC. 47

48 BET During the period an overall TAC was set at 90,000 t. The TAC was later lowered [09-01] & [11-01] to 85,000 t. Estimates of catch for seem to have been always lower than the corresponding TAC. Concern over the catch of small bigeye tuna partially led to the establishment of spatial closures to surface fishing gear in the Gulf of Guinea [Rec ], [Rec ] and [Rec ]. Conclusive evidence that the spatial closures to date have been sufficient to reduce fishing mortality of juvenile bigeye is not available. The closure implemented in Rec may be more effective than those implemented before by Rec and Rec

49 BET [Rec ] [Rec ] 1-30 November 1 Nov 31 Jan [Rec ] [Rec ] [Rec ] 1 Jan - 28 Feb 49

50 BET TAC =85,000 or less would provide a high probability of maintaining at or rebuilding to stock levels consistent with the Convention objectives. The Commission should be aware that if major countries were to take the entire catch limit set under Recommendation and other countries were to maintain recent catch levels, then the total catch could well exceed 100,000 t. The Committee reiterates its concern on the unreported and/or misidentified bigeye tuna catches. 50

51 YFT Last assessment:

52 YFT Yellowfin, Rabil, Albacore Scientific name Distribution Spawning grounds Maturity Life span Thunnus albacares Tropical and subtropical species distributed mainly in the epipelagic oceanic waters The main spawning ground is the equatorial zone of the Gulf of Guinea (January to April). Spawning also occurs in the Gulf of Mexico, in the southeastern Caribbean Sea, and off Cape Verde, although the relative importance of these spawning grounds is unknown Around 100 cm - 3 year old Around 10 years management unit Maximum size Around 230 cm (180 kg) Natural mortality Assumed to be 0.8 for ages 0 and 1, and 0.6 for ages 2+ Uncertainties in both natural mortality and growth have important implications for stock assessment. Younger age classes exhibit a strong association with FADs. This association increases the vulnerability of these smaller fish. 52

53 YFT % average catch in Atlantic YFT, although the second largest volume production of Atlantic tunas at about 110,000 t per year (average ), represents a small proportion of the world-wide production of this species Atlantic YFT tuna represents 9% of the world production (average ). 53

54 YFT Purse seine Longline Baitboat Others 5,000 t 54

55 YFT 7,000 t Purse seine Longline Baitboat Others

56 YFT YFT Catches by main gear type 92,615 t in 2013 % average catch in Historic high of about 194,000 t in After 1991, catches declined to the lowest level in nearly 40 years (96,500 t) in Catch levels for 2013 (92,615 t) are considered provisional. The number of active PS declined by more than half from 1994 until 2006; but then increased since 2007 (piracy in the Indian Ocean; other fleets). 56

57 YFT YFT Catches by main CPC and gear type in ,615 t in

58 YFT YFT free schools & FAD catches YFT free schools & FAD catches Significant catches of YFT (over 1000 tons) were obtained in 2011 by EU PS south of 15 S off the coast of West Africa (in association with skipjack and bigeye on FADs). This area is very special in its environment and low oxygen levels. This was the first time that YFT catches have been obtained by PS in this region, although this species was once dominant in the catches on Angolan BB until

59 YFT CPUE series: Purse seine Baiboat Longline After an initial period of apparent declines, showed high variability without clear trend in recent years Large fluctuations, with a somewhat declining overall trend Declining trend until the mid- 1990s, and have fluctuated without clear trend since 59

60 YFT Average weight of yellowfin tuna by fishing gear Average YFT weight differs between major gears. The recent average weight in EU PS catches has declined to about half of the average weight of 1990 (at least in part due to changes in selectivity associated with fishing on FADs beginning in the 1990s). Trend in YFT average weight for EU PS separated between free schools and FAD associated. 60

61 YFT Catch at age: In terms of selectivity the overall fishery focus has generally evolved since the early 70's of larger/older fish to smaller/younger fish. This evolution in selectivity has implications for how much yield can be taken from the stock while maintaining (or rebuilding) it at a level consistent with the Convention Objective. 61

62 YFT Stock status MSY = 144,600 t (114, ,100 t) 2013 Yield = 92,615 t B 2010 /B MSY = 0.85 ( ) F current /F MSY = 0.87 ( ) There is considerable uncertainty in the assessment of stock status and productivity for yellowfin tuna. 26% of the outcomes indicate the stock is consistent with the Convention Objective. 62

63 YFT Outlook TAC ,000 25% 51% 70% 78% 84% 87% 89% 91% 92% 93% 94% 95% 95% 96% 60,000 24% 48% 66% 76% 81% 85% 87% 89% 90% 92% 93% 93% 94% 94% 70,000 24% 45% 63% 73% 78% 82% 85% 87% 89% 90% 90% 92% 92% 93% 92,615 t in 2013 TAC 110,000 t 80,000 24% 43% 59% 69% 75% 79% 82% 84% 86% 87% 88% 89% 90% 90% 90,000 24% 40% 54% 65% 71% 75% 78% 81% 82% 84% 85% 86% 87% 88% 100,000 24% 37% 49% 59% 66% 70% 73% 76% 78% 80% 81% 82% 83% 84% 110,000 23% 35% 45% 53% 59% 64% 67% 70% 72% 74% 75% 76% 77% 78% 120,000 23% 32% 40% 46% 51% 55% 58% 61% 64% 65% 66% 68% 69% 70% 130,000 23% 29% 35% 39% 43% 45% 47% 49% 51% 53% 54% 55% 56% 58% 140,000 22% 26% 29% 31% 33% 34% 36% 36% 37% 38% 39% 39% 40% 40% 150,000 20% 21% 22% 22% 22% 21% 21% 21% 21% 21% 21% 21% 20% 20% Maintaining current TAC= 110,000 t [Rec ] is expected to lead to a biomass somewhat above B MSY by 2016 with a 60% probability. Reported catches for are lower than the corresponding TAC. 63

64 YFT Spatial closures to surface fishing gear in the Gulf of Guinea [Recs , 99-01, 04-01, 08-01, 11-01]. Larger time/area moratoria are likely to be more precautionary than a smaller moratoria, providing that the moratoria are fully complied with. Rec also implemented a TAC of 110,000 t for 2012 and subsequent years. In 1993, the Commission recommended that there be no increase in the level of effective fishing effort exerted on Atlantic YFT, over the level observed in Effective effort in 2010 appeared to be near the 1992 levels. 64

65 YFT Atlantic YFT stock was estimated to be overfished in Continuation of catch levels of 110,000 t is expected to lead to a biomass somewhat above B MSY by 2016 with a 60% probability. Catches approaching 140,000 t or more would reduce the chances of meeting Convention Objectives below 50%, even after 15 years (2025). The Committee continues to recommend that effective measures be found to reduce FAD-related and other fishing mortality of small YFT. The Committee notes that the closure implemented in Rec may be more effective than that implemented by [Rec ]. 65

66 SUMMARY Tropical tunas Skipjack Bigeye Yellowfin

67 SCRS Evaluate the efficacy of the area/time closure referred to in paragraph 20 for the reduction of catches of juvenile BET and YFT ---- Rec. [11-01] paragraph 22

68 18.1 Tropical tunas 18.1 Evaluate the efficacy of the area/time closure referred to in paragraph 20 for the reduction of catches of juvenile BET and YFT ---- Rec. [11-01] paragraph 22 [Rec ] 1 Jan - 28 Feb The closure went into force at the beginning of The Committee is limited in the extent to which it can evaluate the effectiveness of this measure 68

69 18.1 Tropical tunas 18.1 Evaluate the efficacy of the area/time closure referred to in paragraph 20 for the reduction of catches of juvenile BET and YFT ---- Rec. [11-01] paragraph 22 Historically, less than 10% of the annual FAD associated catches of YFT and BET are caught within the area/time closure. These catches are predominantly of small fish. Substantial changes in the tropical tuna catch concurrent with the closure in 2013: EU and associated fleets: FAD catches in the moratorium area immediately after the closure were high, but at the same high level observer in the historic time series. There were few reported free school catches within the closure area, despite that being permitted by Rec They more or less maintained its catches during the closure by fishing outside the closure area on FAD and free schools. FAD catches from the Ghanaian fleet during the closure season were much lower than in previous years. 69

70 SCRS Recommendations - Work plan 70

71 Recommendations Work Plan Tropical tunas TT General to the Commission that have financial implications Importance of the implementation of a large-scale tagging program for tropical tuna species (AOTTP). EU has expressed interest in funding 80% of the budget if others co-fund the remaining 20% and with the condition that no more than half of the co-funding is in-kind. Total in 5 years Total (x1,000 ) 16,876 EU funding 13,500 Co-Funding total 3, /year Cash 1, /year In kind 1, /year Support cooperation between Ghanaian and IRD scientists in order to complete de development of the T3+ software necessary for the treatment of Ghanaian statistics (SCRS/2014/192) [ 38,500 ] Peer review of the BET stock assessment [ 12,000 ] 71

72 Recommendations Work Plan Tropical tunas Other Temporary Working Group on FADs Members: scientists, fishery managers, fishing industry administrators and fishermen. Objectives : a) initiate an active exchange of views concerning FAD management options; b) better estimate the past and present numbers of buoys, FADs and changes in FAD-related technology; c) evaluate ways to improve the use of information related to FADs in the process of stock assessment, d) evaluate the consequences of future FAD-related management options on ICCAT-managed species and on the pelagic ecosystems. 72

73 Recommendations Work Plan Tropical tunas Other The Committee reiterates the need to obtain economic data on the commercial category landing values of the various species managed by ICCAT. The Committee therefore recommends that ICCAT collates this information and creates a database of historic tuna prices for species harvested in the ICCAT Convention area. 73

74 Recommendations Work Plan Tropical tunas Feb Mar Apr May Jun Jul Aug Sep Oct Complete the re-estimation of the historic Ghanaian statistics for BET and YFT 2. BET data preparatory and assessment meeting in First meeting of the FAD-WG 4. Update of analysis of moratoria 5. YFT data preparatory and assessment meeting in 2016 Initiation of the tropical tuna tagging program Nov Dec 5 74