October Pelagic Advice Pelagic AC 1 October 2014 John Simmonds ICES ACOM Vice Chair Overview WG 1 NEA Mackerel WG 2 Stocks Blue whiting NS horse mackerel Southern horse mackerel boarfish Management plans North Sea HM. General point on discard estimates Landings / Catch advice ICES has followed a policy in 2014 of providing advice based on catch where possible. Several assessments in this group have estimates of discards for part of the fleet, which is usually included in the data, though the extent varies from year to year. Where discard proportions are know ICES gives catch advice directly, where discard estimates are available and when raised to fleet are thought to be less than 5% ICES considers discards to be negligible and gives catch advice. Uncertainties of this order are small compared to other uncertainties in the advice. Norwegian spring spawning herring Recent s to Persistent retrospective revision of SSB downwards and F upwards Initial estimates of recruitment tend to be high. 1
Outlook catch options 2015 Short / Medium term prognosis Rationale Agreed management plan MSY approach Catches Basis F w 1) SSB(2016) % SSB % TAC 283 F MP 0.080 3192 9 32 367 F MSY (SSB 2015 /MS Y B trigger ) 0.105 3120 11 12 Zero catch 4) 0 F = 0 0 3437 2 100 Other options 373 F 2014 0.107 3115 11 11 512 F MSY, F pa 0.150 2995 14 22 Following the long-term management plan of EU, Faroe Islands, Iceland, Norway, and the short term prognoses is that SSB declines from 4 million tonnes in 2014 to 3.5 and 3.2 million tonnes in 2015 and 2016, (assuming catches are taken) As SSB declines clause 3 in the management plan reduces F and recommends lower catches has episodic recruitment with infrequent large yearclassess. Recent yearclasses are relatively small though early indications of recruitment in 2013 are a little higher. It takes around 4 years for recruitment to enter the fishery. The extent of the present period of low recruitment is unknown and may continue for a number of years. Based on MP simulations in 2013 SSB is expected fluctuate above Blim and below Bpa until recruitment improves. (Summary) Status The stock is declining and estimated to be below B pa in 2013. Since 1998 five large year classes have been produced (1998, 1999, 2002, 2003, and 2004). However, available information indicates that year classes born between 2005 and 2012 have been small. Fishing mortality in 2013 was at F pa and F MSY, but above the management plan target F. approach (F pa, F lim) Management plan (F MGT) approach (B pa, B lim) Management plan (SSB MGT) Appropriate Harvested sustainably Above limit Below trigger Increased risk Below target North East Atlantic mackerel Advice 2015: ICES advises on the basis of the management plan of EU, Faroe Islands, Iceland, Norway, and Russia that catches in 2015 should be no more than 283 013 t. Minor discards are known to take place, but cannot be quantified accurately; the proportion of discards in the total catches are considered negligible. NEA mackerel Recent s to Benchmark revision in early 2014 (2013 assessment carried out in May 2014). Recruitment is poorly estimated (2013 from a survey and 2014 using geometric mean) 2
Rationale Managem ent plan MSY framewor k Precautio nary approach NEA mackerel Catch F (2015 & 2016) 906 0.22 869 0.21 831 0.20 Basis F(management plan upper boundary) 0.22 F(management plan mid-point) 0.21 F(management plan lower boundary) 0.20 Outlook catch options 2015 SSB Spawning time SSB (2016) Spawning time SSB TAC 4 372 4 304 2% 35% 4 379 4 339 1% 38% 4 386 4 375 0% 40% 1 017 0.25 F MSY 4 351 4 197 4% 27% 1 054 0.26 Fpa 4 344 4 163 4% 25% Zero catch 0 0 F = 0 4 528 5 193 15% 100% NEA mackerel (Summary) Status Fishing mortality in 2013 is estimated to be 0.22, below FMSY and Fpa. SSB has increased considerably since 2002 and remains high, above Bpa and MSY Btrigger. The 2002 and 2006 year classes are the strongest in the timeseries. The incoming 2011 and 2012 year classes appear to be high. Advice 2015: approach (F pa,f lim) Management plan (F MGT) approach (B pa,b lim) Management plan (SSB MGT) Appropriate Harvested sustainably At target Above trigger Full reproductive capaci Above trigger ICES advises on the basis of the Norway, Faroe Islands, and EU management plan that catch in 2015 should be between 831 000 tonnes and 906 000 tonnes. ICES advises that the existing measures to protect the North Sea spawning component should remain in place. Blue whiting Blue whiting Blue whiting Recent s to Blue Whiting Outlook catch options 2015 Rationale Catch Basis Management plan 839.886 924.713 1130.007 Management plan, F = 0.18 Management plan, F = 0.20 Management plan, F = 0.25 F 2015 SSB (2016) % SSB 1) % TAC 2) 0.18 5904.242 3 30 0.20 5824.446 2 23 0.25 5631.561 2 6 F pa 0.32 1401.963 F pa 0.32 5376.574 6 17 F lim 0.48 1962.330 F lim 0.48 4853.303 15 64 MSY framework 1326.035 F MSY = 0.30 0.30 5447.701 5 11 Zero catch 0 F = 0 0.00 6696.989 17 100 3
Blue whiting (Summary) Status SSB has almost doubled from 2010 (2.9 million tonnes) to 2014 (5.5 million tonnes) and is well above B pa (2.25 million tonnes). This increase is due to the lowest Fs in the time-series in 2011 2013, in combination with increased recruitment since 2010 (at age 1). approach (F pa, F lim) Management plan (F MGT) approach (B pa, B lim) Management plan (SSB MGT) Appropriate Harvested sustainably Below target Above trigger Full reproductive capacity Above trigger Advice for 2015 ICES advises on the basis of the management plan agreed by Norway, the EU, the Faroe Islands, and Iceland that catches in 2015 should be no more than 839 886 tonnes. All catches are assumed to be landed. Changes in The assessment estimate of SSB is very uncertain, and historically it has revised the perception of the development of the stock over time. When a new survey index is introduced to the data every three years (as in 2013) the assessment is rescaled to the most recent survey observation. The effect of this rescaling is to significantly the yield advice and the perception of mortality in the stock. The assessment has no independent information to determine whether increased proportions of young fish in the catches are due to increased mortality or increased recruitment. Currently this situation is explained as increased mortality in the assessment, implying low recruitment. Changes in the approach from 2013 The basis for the assessment has not d from last year. Rationale Catch Basis F Outlook catch options 2014 SSB 1) SSB %SSB (2016) 1) 2) % TAC 3) The advice this year is the given based on MSY approach. However, the fishing mortality is modified by a biomass constraint based on MSY B trigger, which is based on SSB in 2001 (lowest biomass). Note that the TAC advice based on the MSY approach results in an SSB in 2015 which would be the lowest in the time-series. Advice is based on catch, assuming negligible discards. The ICES assessment is based on a combination of landings and partial discard data, so the assessment does not represent only landings and cannot be used directly to give landings advice. Some discarding is known to occur, though estimates for all fleets are not available. In 2013 62% of landings have discard estimates; if the same discard rate is assumed for the remaining fleets overall discard rates are estimated to be 4.1%, which ICES considered negligible. MSY approach 99 304 F MSY (SSB 2015 / B trigger ) 0.12 530 407 480 681 10 27 Zero catch 0 F = 0 0 561 864 576 528 3 100 Other options 108 336 115 107 20% TAC reduction 15% TAC reduction 0.14 527 361 472 030 12 20 0.14 525 196 465 947 13 15 138 436 F 2013 0.18 517 476 444 696 16 2 135 420 Roll-over TAC 0.17 518 328 447 008 16 0 155 733 162 504 15% TAC increase 20% TAC increase 0.20 511 552 428 848 19 15 0.21 509 453 423 327 20 20 4
Catch in tonnes 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 10/8/2014 (Summary) Stock status The SSB declined steadily between 1988 and 2000 and has varied between 634 577 tonnes in 2001 and 1 506 950 tonnes in 2009. SSB is estimated to be at 772 334 tonnes in 2013 and is expected to decline below MSY B trigger in 2014. Fishing mortality has been increasing since 2007 and has been above F MSY since 2012. Recruitment has been low from 2004 onwards.. Advice for 2015 approach (F pa, F lim) approach (B pa, B lim) Above target Undefined Above Undefined North Sea horse mackerel ICES advises on the basis of the MSY approach that catches in 2015 should be no more than 99 304 t. North Sea horse mackerel Changes from 2013 60000 50000 40000 30000 20000 catch In 2013 ICES advice was based on historical catches (category 5). ICES has developed an new index of biomass for this stock and during the evaluation of a potential management plan (ICES Advice July 2014), ICES developed six exploratory assessments and evaluated a proposed harvest control rule for a multi-annual plan for horse mackerel in the North Sea. The information coming from this study has d both the perception of the state of the stock and the perception of the current exploitation rate. 10000 0 Due to this ICES considers that it can no longer give category 5 (catch only) advice but has d the basis of the advice to category 3 precautionary/msy considerations, based on both the survey index and the exploratory assessments. The survey index indicates that the stock biomass has been relatively stable over the last 7 years. The exploratory assessments (Table 6.2.3.3.1 of ICES, 2014a) show that the exploitation rate is currently well above any candidate F MSY reference points. So the current perception is now of a stock with stable biomass with uncertain but high exploitation rate. Status North Sea horse mackerel (Summary) The available information, while broadly informative, is insufficient to evaluate 2013 biomass and exploitation status. Catches in recent years have been declining slowly, with an average around 23 kt (2011 2013). Advice for 2015 approach (F pa,f lim) Qualitative evaluation approach (B pa,b lim) Qualitative evaluation 2011 2013 Likely above target 1 2011 2013 Likely below target 1 Southern horse mackerel ICES advises a significant reduction in catch of greater than 20%, corresponding to catches in 2015 of less than 15 200 t. 5
Southern horse mackerel Southern horse mackerel Recent s to Assessment shows relatively stable stock with low fishing mortality. The lack of contrast over time and the low fishing mortality make the scaling of the assessment uncertain Southern horse mackerel Rationale Catches T. trachurus Basis F SSB SSB 1) (2016) %SSB 2) % Catch 3) MSY 71.824 F MSY 0.11 545.920 536.947-2% +135% approach (F 2014 2.4) Zero catch 0 0 0 551.115 612.215 11% -100% 6.307 Other options 12.554 18.740 24.867 F 2014 0.2 0.009 F 2014 0.4 0.019 F 2014 0.6 0.028 F 2014 0.8 0.037 Outlook catch options 2015 550.680 605.544 10% -79% 550.245 598.948 9% -59% 549.811 592.427 8% -39% 549.377 585.979 7% -19% 30.936 F 2014 0.046 548.944 579.604 6% 1% 36.947 F 2014 1.2 0.056 548.511 573.301 5% 21% Management considerations Due to the missing survey in 2012 the assessment and current recruitment estimates are more uncertain than usual. Managers may want to consider limiting the increase in catch Currently, fishing mortality is well below the F MSY proxy. Following the MSY approach implies increasing current fishing mortality by a factor of 2.4. Keeping the fishing mortality in 2015 at the level of 2014 (0.046) would imply catches of 31 000 t for Trachurus trachurus. The TAC is set for all Trachurus species, in 2011, 12% of the catches consisted of other species than T. trachurus, (% varies from year to year). Assuming a similar proportion of other Trachurus species in 2015, would result in a catch of all Trachurus species of 35 000 t. Southern horse mackerel (Summary) Stock Status Fishing mortality has been below F MSY over the whole time series and the SSB has been relatively stable. Recruitment is estimated to be well above average in 2011 and 2012. approach (F pa,f lim) approach (B pa,b lim) Qualitative evaluation Appropriate Not defined Not defined Not defined At long term aver boarfish Advice for 2015 ICES advises on the basis of the MSY approach that catches should be no more than 71 824 t in 2015. 6
Boarfish Boarfish Changes from 2013 The basis of advice has d over the last 4 years. In 2011, the advice was based on average catches in 2008 2010. In 2012, the advice was based on the 2012 acoustic biomass survey estimate and an F MSY proxy. In 2013 the advice was based on the results of a Schaefer surplus production model and followed the MSY approach. The Schaefer surplus production model now indicates exploitation rates are low and biomass is declining from a high. It is no longer considered suitable for category 1 advice, because uncertainty is not handled consistently with a rapid increase in the last two years as the model follows the acoustic survey too closely. This leads to potential over estimation of decline in TSB over the last two years. While the Schaefer surplus production model provides indications of trends, these are not considered reliable enough to form the basis for assessment. Therefore the 2014 ICES advice is based on the data-limited approach, using the Schaefer model as an indicator of trends. Boarfish ICES approach to data-limited stocks For this stock, the Schaefer surplus production model biomass index is estimated to have decreased more than 20% between the periods 2010 2012 and 2013 2014. This implies a decrease in catch capped at 20% in relation to the last three years average (2011 2013), corresponding to catches in 2015 of no more than 53 296 t. The same model shows that exploitation rate in recent years is low (less than or equal to any candidate F MSY reference points) and this exploitation rate is considered not detrimental to the stock; therefore, no additional precautionary reduction is needed. Boarfish (Summary) Stock status The stock status is currently unknown. Survey indices (Figure 9.3.6.4) and an exploratory assessment (Figure 9.3.6.1) indicate that the stock is declining. Fishing mortality is low. Advice for 2015 approach (F pa, F lim) Qualitative evaluation approach (B pa, B lim) Qualitative evaluation 2011 2013 ICES advises on the basis of the data-limited approach that catches in 2015 should be no more than 53 296 t. Low Decreasing 2012 2014 Special request MP NS horse mackerel ICES Advice issued in July 2014 ICES has evaluated the proposed harvest control rule for a multiannual plan for horse mackerel in the North Sea using various plausible parameter options. Given that the stock is at its lowest since the early 1990s, some of the Harvest Control Rule parameter options suggest recovery of the stock to above the present level by 2020, but none of them with 95% probability. Therefore, ICES considers none of these options as being in accordance with the precautionary approach. It is suggested that managers discuss other options with ICES that might be more suitable, including a recovery phase to reverse the decline of the stock. Basis :- This stock is data limited, with no benchmarked analytical assessment to assess the stock status and provide a formal basis for parameterising the evaluation. A stock assessment modelling framework was used to provide multiple plausible estimates of stock dynamics. All these estimates the stock is considered to be at the lowest level since the early 1990s. These were used as a basis for the evaluation of the proposed HCRs. Approach:- ICES tested a number of options for HCR parameters (λ, Slp, Itrig, TACstabilizing). The results of the evaluations are based only on a limited but broadly reasonable selection of parameter options. Currently ICES has not had sufficient time to explore alternative HCRs, such as HCRs with a specific early stock rebuilding phase. Criteria: The standard ICES criteria were applied: Plan is precautionary if the probability of SSB falling below B lim is less than 5%. ICES considers that a necessary condition for MSY exploitation is that the stock is within safe biological limits, here than means SSB has less than 5% probability of being below B lim by 2015 or 2020 at the latest as defined in the request. As there is currently no agreed assessment or reference points, B loss (SSB in 2012 = 27 000 t) was used as a proxy for B lim. 7
Yield Biomass Based on the HCRs tested assuming the catches in 2014 are no more than 20 000 t, the HCR options tested show that F does not reduce to F MSY in 2015, or 2020. However, assuming the catches in 2014 are no more than 5000 t, the HCR options tested show that F is reduced to below F MSY in 2015. However, none of these options will result in the stock being within safe biological limits by 2020. A potential candidate value for F MSY is 0.12. Average F over the last 3 years (2010-2012) has much greater than this. Results:- Conclusion:- The evaluations show that because of the current poor state of the stock, short term considerations that stop stock decline outweigh any potential long term performance, as current catches are not thought to be sustainable. With the limited data used in the assessment and the uncertainty associated with the resulting stock dynamics (stock recruitment relationship in particular), longer term implications are highly dependent on the assumptions made in the assessment model and forecast model. Nevertheless the immediate concern is to decrease fishing mortality and prevent further decline of the stock. NEAFC questions on blue whiting A significant reduction in F is needed to increase biomass and reduce F to Fmsy (This aspect of the study is included when advising a significant reduction in catch for 2015.) NEAFC Request on blue whiting 1) The North-East Atlantic Fisheries Commission (NEAFC) has noted that ICES in its blue whiting forecast for 2014, assumed the level of recruitment in 2013 to be the same as that in 2012 rather than the geometric mean of the years 1981-2010, which means the spawning biomass in 2015 might be overestimated. 2) Furthermore, NEAFC noted that the distribution of spawning biomass estimates using the stochastic forecast model is both wide and skewed, which in its view could lead to an overestimation of the F values that are deemed precautionary. 3) ICES is requested to review the assumptions and performance of the stochastic forecast model. ICES is also requested to assess whether or not there are any implications with respect to the reliability of its previous evaluations of the various options to revise the management plan, as outlined in special requests 9.3.3.1 and 9.3.3.7 of June and October 2013 respectively. ICES Response to NEAFC Request on blue whiting 1) The value for 2012 recruitment was correct. There was an error in the input recruitment value for 2013. by mistake, recruitment as estimated for 2012 was used. This error led to a 2% higher TAC advice and a slightly higher SSB than if the GM recruitment had been applied. 2) The distribution of the spawning-stock biomass estimates have not been used to infer precautionary considerations. In 2014 ICES is using a deterministic forecast method for blue whiting. 8
ICES Response to NEAFC Request on blue whiting (continued) 3) ICES has reviewed the performance of the stochastic forecast model and has determined that there are differences between the stochastic and the deterministic forecast models. The magnitude of the difference depends on the uncertainty in results from the assessment model. For blue whiting catch advice in 2015 the stochastic forecast produces a TAC that is 4 to 5% higher than a deterministic forecast. ICES advises that a deterministic forecast is used as basis for the TAC advice for 2015 in order to be consistent with the assumptions made in both the 2013 (ICES, 2013a, 2013b) and the 2008 (ICES, 2008; Anon., 2008) management strategy evaluations of this stock. 9