Mackerel (Scomber scombrus) in subareas 1 7 and 14, and in divisions 8.a e and 9.a (Northeast Atlantic)

Transcription

1 ICES Advice on fishing opportunities, catch, and effort Northeast Atlantic Published 30 September Mackerel (Scomber scombrus) in subareas 1 7 and 14, and in divisions 8.a e and 9.a (Northeast Atlantic) ICES stock advice ICES advises that when the MSY approach is applied, catches in 2017 should be no more than tonnes. ICES further advises that the existing measures to protect the North Sea spawning component should remain in place. Stock development over time The spawning-stock biomass (SSB) is estimated to have increased since the early 2000s and has been above MSY Btrigger since The fishing mortality (F) has been declining from high levels in the mid-2000s but remains above FMSY. There has been a succession of large year classes since the early 2000s (2002, 2006, 2011, and 2014) and all year classes since 2005 (except for the 2013 year class) are estimated to be above average. Figure Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. Summary of stock assessment. The unshaded catches prior to 2000 are the years that have been down-weighted in the assessment because of the considerable underreporting that is suspected to have taken place. The recruitment value for 2015 is from RCT3 and the unshaded recruitment value for 2016 is the geometric mean of Confidence intervals (95%) are included in the recruitment, fishing mortality, and spawning-stock biomass plots. ICES Advice 2016, Book 9 1

2 Published 30 September 2016 ICES Advice on fishing opportunities, catch, and effort Stock and exploitation status Table Maximum sustainable yield Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. State of the stock and fishery relative to reference points. Fishing pressure Stock size F MSY Above MSY B trigger Above trigger Full Precautionary F pa, approach F Increased risk B lim pa, B lim reproductive capacity Management plan F MGT Not applicable SSB MGT Not applicable Catch options for 2017 Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. The basis for the catch options for Variable Value Source Notes F ages 4 8 (2016) 0.24 ICES (2016a) Based on the ICES estimate of the total catch for SSB (2016) spawning time (May) t ICES (2016a) Based on the ICES estimate of the total catch for R age 0 (2016) thousands ICES (2016a) R age 0 (2017) thousands ICES (2016a) R age 0 (2018) thousands ICES (2016a) Total catch (2016) t ICES (2016a) Geometric mean of the recruitment estimates ( ). Sum of declared quotas corrected by the interannual transfers. Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. The catch options for F (2017 Catch SSB (2017) SSB (2018) Rationale & Basis (2017) Spawning time Spawning time 2018) MSY approach SSB change* Catch change** F MSY % 12% F = % 100% F in the EU, Faroe Islands, and Norway long-term management % 4% strategy F(2016) % 4% Catch(2017) = 2016 catch 20% % 20% Catch(2017) = 2016 catch % 0% Catch(2017) = 2016 catch +20% % 20% Other % 8% options % 3% % 6% % 10% F pa % 1% F lim % 36% F( ) leading to B pa in % 153% F( ) leading to B lim in % 293% Weights in tonnes. * SSB 2018 relative to SSB ** Catch in 2017 relative to estimated catches in There is no internationally agreed TAC for ICES Advice 2016, Book 9

3 ICES Advice on fishing opportunities, catch, and effort Published 30 September 2016 Basis of the advice Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. The basis of the advice. Advice basis MSY approach. The EU, Faroe Islands, and Norway have agreed on a long-term management strategy for NEA mackerel Management plan (Anon., 2015). ICES has not yet evaluated this management strategy and not all parties involved in the mackerel fishery have taken part in the agreement. Quality of the assessment The surveys give contradictory information on the recent development of the stock. The 2016 egg survey suggests a decrease in the SSB since 2013 while the abundances-at-age from the IESSNS index have increased between those years. As a result of this discrepancy, in this year s assessment, the surveys have less influence on the estimated stock abundance than the catch information. Year-to-year changes in the indices from surveys carried out during the assessment year, for which no catch information is available, have caused substantial changes in the scale of the stock over the last ten years. The lower estimate of SSB in the 2015 assessment compared to the 2014 and 2016 assessments (Figure ) was mostly caused by a low value in the IESSNS index in Figure Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. Historical assessment results (final-year recruitment estimates included). Issues relevant for the advice The IBTS recruitment index was used incorrectly in the 2015 mackerel assessment. A correction of the advice issued last year for 2016 was released in September The assumption made on intermediate year catch for the advice for 2017 is based on the declared TACs. There are considered to be three components to the NEA mackerel stock: western, southern, and North Sea (ICES, 2016b). The results of the recent egg surveys indicate a decrease in the relative importance of the southern component (from 24% of the mackerel stock in 2013 to 11% in 2016). While the biomass of the western component estimated by the egg survey also decreased in the same period, its relative contribution to the mackerel stock increased from 73% to 85%. The biomass of the North Sea component (egg survey conducted in 2015) remains stable at a low level and its relative contribution to the stock increased from 3% to 4%. ICES Advice 2016, Book 9 3

4 Published 30 September 2016 ICES Advice on fishing opportunities, catch, and effort Reference points Table Framework MSY approach Precautionary approach Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. Reference points, values, and their technical basis. Reference point Value Technical basis Source MSY B trigger 3 million t B pa ICES (2015) F MSY 0.22 Stochastic simulation. ICES (2015) B lim 1.84 million t B loss in 2002 from 2014 benchmark assessment. B pa 3 million t exp(1.654 σσ) B lim, σσ = ICES (2015) F lim 0.36 The F that on average leads to B lim. ICES (2015) F pa 0.25 The F that on average leads to B pa. ICES (2015) Basis of the assessment Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. The basis of the assessment. ICES stock data category 1 (ICES, 2016c). Assessment type 1.0 age-based analytical model (SAM: ICES, 2016a) that uses catches in the model and in the forecast. Catch data, tagging data ( recapture year), and three survey indices: SSB index from the triennial egg survey ( ), abundance indices from the IBTS survey (combined Q1 and Q4; age 0, ), Input data and from the IESSNS survey (ages 6 11, 2007, ). Catches prior to 2000 are given a very low weight in the assessment. Natural mortality (= 0.15 for all ages and years) is based on tagging studies from the early 1980s. Discarding is known to take place, but is only quantified for part of the fisheries (0.8% in weight in 2015); Discards the proportion of the landings covered cannot be calculated. Partial discard estimates are included in the assessment and overall discarding is considered negligible. Indicators None Other information Benchmarked in 2014 (WKPELA; ICES, 2014). A benchmark is planned for Working group Working Group on Widely Distributed Stocks (WGWIDE) Information from stakeholders Over the last eight years the pelagic industry has encountered large shoals of mackerel over the entire distribution area which has expanded both south and north. Based upon these observations the industry believes the stock size has greatly increased. This increase in the stock is not confined to one area or observed by only one fleet. The industry has noted signs of good recruitment (above average) in recent years, particularly in 2014 and Mackerel is also caught in substantial amounts outside of the directed mackerel fishery and in places where it has not been caught in recent years (e.g. during the herring fishery in the North Sea). Danish fishers have reported catches of spawning mackerel in the sandeel fishery. 4 ICES Advice 2016, Book 9

5 ICES Advice on fishing opportunities, catch, and effort Published 30 September 2016 History of advice, catch, and management Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. History of ICES advice, the agreed TAC, and ICES estimates of catch. Year ICES advice Predicted catch Disc.*** Total agreed TAC* Official landings** corresp. to advice & slipping ICES catch 1987 Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Significant reduction in F Significant reduction in F F between 0.15 and F of 0.15 consistent with PA n/a F = 0.17: F pa F = 0.17: F pa F = 0.17: F pa F = 0.17: F pa F = 0.17: F pa F = 0.15 to 0.20 [ ] F = 0.15 to 0.20 [ ] ^ F = 0.15 to 0.20 [ ] F = 0.15 to 0.20 [ ] F = 0.15 to 0.20 [ ] 605^^ harvest control rule [ ] 885^^^ See scenarios [ ] 959^^^ Follow the management plan [ ] 927^^^ Follow the management plan [ ] 906^^^ Follow the management plan [ ] 1392^^^ Follow the management plan [ ] 1229^^^ MSY approach ^^^ 2017 MSY approach 944 Weights in thousand tonnes. n/a: not available. * For all areas, except some catches in international waters in Subarea 2. ** Updated with ICES FishStat data. *** Data on discards and slipping from only two fleets. ^ Incomplete. ^^ Does not include the unilateral Norway/Faroe Islands TAC first declared in 2009, nor the Icelandic quota. ^^^ No internationally agreed quotas. Values presented are the sum of unilateral quotas. Catch advice for 2016 corrected in September ICES Advice 2016, Book 9 5

6 Published 30 September 2016 ICES Advice on fishing opportunities, catch, and effort Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. History of ICES advice, the agreed TAC, and ICES estimates of catch for the Western component. Year ICES advice Predicted catch corresp. to advice Agreed TAC* Disc. & slipping ICES catch** 1987 SSB = 1.5 mill. t; TAC F = F 0.1; TAC; closed area; landing size Halt SSB decline; TAC TAC; F = F TAC; F = F TAC for both 1992 and TAC for both 1992 and No long-term gains in increased F 831*** % reduction in F No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice - ^ No separate advice - ^ No separate advice - ^ No separate advice - ^ No separate advice - ^ No separate advice - ^ No separate advice - ^ 2017 No separate advice - Weights in thousand tonnes. * TAC for mackerel taken in all divisions and subareas 6, 7, 8.a, 8.b, 8.d, 5.b, 2.a, 3.a, and 4.a. ** Landings and discards of the Western component; includes some catches from the North Sea component. *** Catch at status quo F. ^ No internationally agreed TAC. 6 ICES Advice 2016, Book 9

7 ICES Advice on fishing opportunities, catch, and effort Published 30 September 2016 Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. History of ICES advice, the agreed TAC, and ICES estimates of catch for the North Sea component. Year ICES advice Predicted catch corresp. to advice* Agreed TAC** ICES catch 1987 Lowest practical level LPL Closed areas and seasons; min. landing size; bycatch regulations LPL Closed areas and seasons; min. landing size; bycatch regulations LPL Closed areas and seasons; min. landing size; bycatch regulations LPL Closed areas and seasons; min. landing size; bycatch regulations LPL 65.5 n/a 1992 Closed areas and seasons; min. landing size; bycatch regulations LPL 76.3 n/a 1993 Maximum protection; closed areas and seasons; min. landing size LPL 83.1 n/a 1994 Maximum protection; closed areas and seasons; min. landing size LPL 95.7 n/a 1995 Maximum protection; closed areas and seasons; min. landing size LPL 76.3 n/a 1996 Maximum protection; closed areas and seasons; min. landing size LPL 52.8 n/a 1997 Maximum protection; closed areas and seasons; min. landing size LPL 52.8 n/a 1998 Maximum protection; closed areas and seasons; min. landing size LPL 62.5 n/a 1999 Maximum protection; closed areas and seasons; min. landing size LPL 62.5 n/a 2000 Maximum protection; closed areas and seasons; min. landing size LPL 69.7 n/a 2001 Maximum protection; closed areas and seasons; min. landing size LPL 71.4 n/a 2002 Maximum protection; closed areas and seasons; min. landing size LPL 72.9 n/a 2003 Maximum protection; closed areas and seasons; min. landing size LPL 62.5 n/a 2004 Maximum protection; closed areas and seasons; min. landing size LPL 57.7 n/a 2005 Maximum protection; closed areas and seasons; min. landing size LPL 44.9 n/a 2006 Maximum protection; closed areas and seasons; min. landing size LPL 47.1 n/a 2007 Maximum protection; closed areas and seasons; min. landing size LPL 53.1 n/a 2008 Maximum protection; closed areas and seasons; min. landing size LPL 48.6 n/a 2009 Maximum protection; closed areas and seasons; min. landing size LPL 63.8 n/a 2010 Maximum protection; closed areas and seasons; min. landing size LPL - n/a 2011 Maximum protection; closed areas and seasons; min. landing size LPL - n/a 2012 Maximum protection; closed areas and seasons; min. landing size LPL - n/a 2013 Maximum protection; closed areas and seasons; min. landing size LPL - n/a 2014 Maximum protection; closed areas and seasons; min. landing size LPL - n/a 2015 Maximum protection; closed areas and seasons; min. landing size LPL - n/a 2016 Maximum protection; closed areas and seasons; min. landing size LPL 2017 Maximum protection; closed areas and seasons; min. landing size LPL Weights in thousand tonnes. LPL = Lowest Practical Level. * Subarea 4 and Division 3.a. ** TAC for Subarea 4, divisions 3.a and 3.b d (EU zone), and Division 2.a (EU zone). n/a: no information available. ICES Advice 2016, Book 9 7

8 Published 30 September 2016 ICES Advice on fishing opportunities, catch, and effort Table Subareas 1 7 and 14 and divisions 8.a e and 9.a. History of ICES advice, the agreed TAC, and ICES estimates of catch for the Southern component. Year ICES advice Predicted catch corresp. to advice Agreed TAC* ICES catch 1987 Reduce juvenile exploitation Reduce juvenile exploitation No advice Reduce juvenile exploitation Reduce juvenile exploitation No advice No advice No advice No advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice - Weights in thousand tonnes. *Division 8.c, subareas 9 and 10, and CECAF Division (EU waters only). History of catch and landings Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. Catch distribution by fleet in 2015 as estimated by ICES. Total catch Landings Discards Discarding is known to take place but is Pelagic trawl Purse-seine nets Others only quantified for part of the fisheries t 78.7% 21.2% 0.1% (0.9% in weight in 2015) t t 8 ICES Advice 2016, Book 9

9 ICES Advice on fishing opportunities, catch, and effort Published 30 September 2016 Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. History of catch and landings, both the official and ICES estimated values are presented by country (combined Southern, Western, and North Sea spawning components). Country Belgium Denmark Estonia Faroe Islands France Germany, Fed. Rep Germany, Dem. Rep Greenland Guernsey Iceland Ireland Jersey Latvia Lithuania 2085 Netherlands Norway Poland Portugal Romania 2903 Spain Sweden United Kingdom USSR/Russia Misreported Unallocated Discards Total ICES Advice 2016, Book 9 9

10 Published 30 September 2016 ICES Advice on fishing opportunities, catch, and effort Table (continued) Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. History of catch and landings; both the official and ICES estimated values are presented by country (combined Southern, Western, and North Sea spawning components). Country Belgium Denmark Estonia Faroe Islands France Germany, Fed. Rep Germany, Dem. Rep. Greenland Guernsey Iceland Ireland Jersey Latvia Lithuania Netherlands Norway Poland Portugal Romania Spain Sweden United Kingdom USSR/Russia Misreported 6009 Unallocated Discards Total ICES Advice 2016, Book 9

11 ICES Advice on fishing opportunities, catch, and effort Published 30 September 2016 Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. History of catch and landings; both the official and ICES estimated values are presented by area. SUBAREA 7 AND SUBAREA 6 SUBAREAS 3AND 4 SUBAREAS 1, 2, 5,AND 14 DIVISIONS 8.CAND 9.A TOTAL YEAR DIVISIONS 8.A, B, D, E Land Disc Catch Land Disc Catch Land Disc Catch Land Disc Catch Land Disc Catch Land Disc Catch ICES Advice 2016, Book 9 11

12 Published 30 September 2016 ICES Advice on fishing opportunities, catch, and effort SUBAREA 7 AND SUBAREA 6 SUBAREAS 3AND 4 SUBAREAS 1, 2, 5,AND 14 DIVISIONS 8.CAND 9.A TOTAL YEAR DIVISIONS 8.A, B, D, E Land Disc Catch Land Disc Catch Land Disc Catch Land Disc Catch Land Disc Catch Land Disc Catch ICES Advice 2016, Book 9

13 ICES Advice on fishing opportunities, catch, and effort Published 30 September 2016 Summary of the assessment Table Mackerel in subareas 1 7 and 14, and in divisions 8.a e and 9.a. Assessment summary; weights in tonnes and recruitment in thousands. Year Recruitmen t High Low SSB (Spawnin High Low Landings Discards Mean F (ages High Low (Age 0) g time) 4 8) * ** * ** average * RCT3 estimate. ** Geometric mean *** Estimated value from the forecast. ICES Advice 2016, Book 9 13

14 Published 30 September 2016 ICES Advice on fishing opportunities, catch, and effort Sources and references Anon Agreed record of conclusions of fisheries consultations between the Faroe Islands, the European Union, and Norway on the management of mackerel in the Northeast Atlantic for 2016, Clonakilty, 23 October Accessed 30/09/2016 at ICES Report of the Benchmark Workshop on Pelagic Stocks (WKPELA), February 2014, Copenhagen, Denmark. ICES CM 2014/ACOM: pp. ICES EU, Norway, and the Faroe Islands request to ICES to evaluate a multi-annual management strategy for mackerel (Scomber scombrus) in the Northeast Atlantic. In Report of the ICES Advisory Committee, ICES Advice 2015, Book 9, Section ICES. 2016a. Report of the Working Group on Widely Distributed Stocks (WGWIDE), 31 August 6 September 2016, ICES HQ, Copenhagen, Denmark. ICES CM 2016/ACOM:16. ICES. 2016b. Report of the Stock Identification Methods Working Group (SIMWG), by correspondence. ICES CM 2016/SSGEPI: pp. ICES. 2016c. General context of ICES advice. In Report of the ICES Advisory Committee, ICES Advice 2016, Book 1, Section ICES Advice 2016, Book 9