ABSTRACT Stock Assessment Form Small Pelagics Reference Year: 2015 Reporting Year: 2016 This assessment was done in the framework of the CopeMed Working Group on small pelagic species. The meeting held on the 17-20 October in Tangier was attended by experts from Morocco, and Spain, Algeria contributed on-line. Data from 2010 to 2015 in GSA01 and GSA03 have been pooled and XSA model has been run. The stock of sardine is considered sustainably exploited in GSA03 and GSA01 combined. The advice would be not to increase the fishing effort.
Stock Assessment Form version 1.0 (November 2014) Sardine GSA01&03 (Northern and Southern Alboran Sea) Stock assessment form 1 Basic Identification Data... 2 2 Stock identification and biological information... 3 2.1 Stock unit... 3 2.2 Growth and maturity... 3 3 Fisheries information... 5 3.1 Description of the fleet... 5 Morocco (sardine seiners in GSA03)... 8 3.2 Historical trends... 9 3.3 Management regulations... 10 4 Fisheries independent information... 11 4.1 Acoustic survey... 11 4.1.1 Brief description of the method... 11 4.1.2 Spatial distribution of the resources... 12 5 Ecological information... 13 5.1 Protected species potentially affected by the fisheries... 13 5.2 Environmental indexes... 13 6 Stock Assessment... 14 6.1 {Extended Survivor analysis (XSA)}... 14 6.1.1 Model assumptions... 14 6.1.2 Scripts... 14 6.1.3 Input data and Parameters... 14 6.1.4 Tuning data... 15 6.1.5 Results... 15 6.1.6 Robustness analysis... 17 6.1.7 Retrospective analysis, comparison between model runs, sensitivity... 18 6.1.8 Sensitivity analysis... 19 6.1.9 Assessment quality... 23 6.1.10 Reference points... 23 7 Stock predictions... 23 7.1 Short term predictions... 23 7.2 Medium term predictions... 23 7.3 Long term predictions... 23 8 Draft scientific advice... 24 8.1 Explanation of codes... 25 1
1 Basic Identification Data Scientific name: Common name: ISCAAP Group: Sardina pilchardus sardine 35 1 st Geographical sub-area: 2 nd Geographical sub-area: 3 rd Geographical sub-area: 1 3 1 st Country 2 nd Country 3 rd Country Spain Morocco Stock assessment method: (direct, indirect, combined, none) Indirect: Extended Survivor analysis (XSA) model in FLR Authors: M.H. Idrissi 1, P. Torres 2, A. Giráldez 2, M. Iglesias 2, M. González 2, M.J. Meléndez 2, A. Ventero 2, A. Ligas 3, F. Colloca 3 and P. Hernández 4 Affiliation: 1 INRH-Nador and INRH-Tangier, Morocco 2 IEO Centro Oceanográfico de Fuengirola, Spain trad 3 GFCM 4 FAO - CopeMed II 2
2 Stock identification and biological information 2.1 Stock unit The General Fisheries Commission for the Mediterranean (GFCM) stressed the importance of making common assessments of shared stocks of priority species. The joint stock assessment of the main shared stocks in the Mediterranean Sea is considered as an important step to contribute reinforcing the subregional collaboration, and to promote agreed management recommendations for fisheries in the GFCM area. Sponsored by Copemed II there have been three joint assessments between Spain and Morocco for sardine in Alboran Sea, in 2012, in 2015 and the current one. All of them have been submitted to the GFCM WG of assessment of small pelagics, however the participants of the CopeMed working group as well as the SAC and the GFCM stressed the need and encouraged the promotion of new scientific studies to determine if this is a shared stock. CopeMed II is preparing a workshop on stock identification during the first trimester of 2017. 2.2 Growth and maturity Table 2.2-1: Maximum size, size at first maturity and size at recruitment. Spanish data Somatic magnitude measured (LT, LC, etc) LT Units cm Sex Fem Mal Combined Sex Autumn-Winter Maximum size observed 23.6 (2015) 25 (2004-2014) Maximum size observed Spring-summer Size at first maturity 12.63 (2015) 13.35 (2003-2014) Size at first maturity All the coast Recruitment size to the fishery 11.5 (2015) Recruitment size to the fishery Bays 3
Moroccan data Somatic magnitude measured (LT, LC, etc) Sex Fem Mal Combined Maximum size observed Size at first maturity Recruitment size to the fishery LT Units cm 20.5 (2014) 20.2 (2015) 13.5 (2014) 13.6 (2015) Reproduction season Recruitment season Spawning area Nursery area Autumn-Winter Spring-summer All the coast Bays Table 2-2.2: M vector and proportion of matures by size or age. Calculated with Gislasson method for the two GSAs IN 2014 Size/Age Natural mortality Proportion of matures Age 0 1,07 0.30 Age 1 0,75 0.80 Age 2 0,63 1 Age 3+ 0,52 1 Table 2-3: Growth and length weight model parameters. Spain and Morocco data. Sex Units female male Combined Years Growth model Length weight relationship L cm 22.3 2014 K Year -1 0.47 2014 t 0 year -1.48 2014 Data source IEO 2014 a 0.0030 2014 b 3.3260 2014 M (scalar) sex ratio (% females/total) 4
3 Fisheries information 3.1 Description of the fleet Spain The current fleet in GSA 01 the Northern Alboran Sea is composed by 87 units, characterised by small vessels, average TJB 24.7. 16% of them are smaller than 12 m (operational Unit 1), 84% > 12 m (operational Unit 2), and no one is bigger than 24m. The purse seine fleet has been continuously decreasing in the last two decades, from more than 230 vessels in 1980 to 87 in 2015. A strong reduction of larger vessels occurred from 1985 onwards, possibly linked to a decreasing in anchovy catches in Northern Morocco, where a part of that fleet fished under agreement between the countries. Subsequently the fleet continued to decline but more slowly. Although sardine has a lower price than anchovy is an important support to the fishery as it is the most fished species. Catches in the period 1990-2015 has been highly variable, with a minimum of 3000 tons in 1997. Higher catches occurred in 1992 (11000 tons). All period average is about 6000 tons. The two operational units fish the same species, there are no major differences, sardine is the most fished species in their both. Although there is a slight difference in the percentage of mackerel catches, as bigger ships are able to fish species with more swimming ability. Species with a lower economic value are also captured, sometimes representing a high percentage of landings: horse mackerel (Trachurus spp.), mackerel (Scomber spp.), and gilt sardine (Sardinella aurita). The interest about some of these species has been increasing because there is a new market for them; gilt sardine and mackerel, especially the first, are sold for tuna farming. A requirement for such sales is a high yield by fishing day, due to its low economic value. In the case of mackerel it is exported to Portugal. Data used in the assessment correspond to EU-Data Collection Framework. Unit of effort has been effective fishing night by species. Series of CPUE shows a very similar profile to catches. Morocco The purse seiner active fleet last year (2015) in GSA 03 (Moroccan Mediterranean sea) was composed by 113 units, characterized by small vessels, average TJB is 50 tx and 252 horse power. 7% of them are smaller than 12 m (operational Unit 1), 86% of them are between 12 m and 24 m (operational Unit 2), and 7% are bigger than 24m (operational Unit 3). This fleet is based mainly in 4 important ports M'diq, Nador, Al Hoceima and Ras Kebdana with high mobility of seiners between ports following the abundance of resources. In addition there are around one hundred of small scale boats fishing in coastal areas that are not considered in this study due to the lack of reliable statistics from this segment. 5
Landings of small pelagic in the Mediterranean are composed by sardine, sardinella, anchovy, horse mackerel, chub mackerel and others. Sardine and anchovy are the target species of seiners: sardine for its abundance and anchovy for its high commercial value. On the last decade, the total production of sardines in the Mediterranean Moroccan sea, fluctuates between 7000 and 15300 tons/year. Between the years 2005 and 2015, the annual average production of sardines is about 12400 tons. Fig 3.2.1 The analysis of time series of catches of sardines in the last decade since 2005 highlights significant fluctuations from one year to another. The general trend in sardine catches between 2005 and 2008 tended to decline. In 2009, the landings increased to about 15000 tons. Since 2011, catches tended to grow. In the last year, landings are decreasing. Fig 3.2.1 The analysis of the evolution of fishing effort (expressed in effective fishing days) exerted on the sardine stock between 2007 and 2015 shows that fishing effort is variable from one year to another with a growing trend. This is linked to climatic conditions and abundance of the resource. Catch per unit effort CPUE generally varies between 1014 and 1953 kg/day with an average of 1267 kg/day. The general trend is downward. Fig 3.2.2 Table 3-1: Description of operational units exploiting the stock Country GSA Fleet Segment Fishing Gear Class Group of Target Species Species Operational Unit 1* Spain 1 G-Purse Seine (6-12 m) 02-Seine Nets 31- Small gregarious pelagic PIL Operational Unit 2 Spain 1 H-Purse Seine (>12) 02-Seine Nets 31- Small gregarious pelagic PIL Operational Unit 1 Morocco 3 G-Purse Seine (6-12 m) 02-Seine Nets 31- Small gregarious pelagic PIL Operational Unit 2 Morocco 3 H-Purse Seine (12-24 m) 02-Seine Nets 31- Small gregarious pelagic PIL Operational Unit 3 Morocco 3 I-Purse Seine (>24 m) 02-Seine Nets 31- Small gregarious pelagic PIL 6
Table 3.1-2: Catch, bycatch, discards and effort by operational unit in the reference year Operational Units* Fleet (n of boats)* Catch (T or kg of the species assessed) Tons Other species caught (names and weight ) Tons Discards (species assessed) Discards (other species caught) Effort (units) ESP 01 G 02 31-PIL 14 317 Anchovy: 82 Trachurus spp: 447 Scomber spp: 181 Sardinella: 202 Otros: 217 negligible negligible Effective fishing day for species ESP 01 H 02 31-PIL 73 4932 Anchovy: 1007 Trachurus spp: 1870 Scomber spp: 839 Sardinella: 1350 Otros: 1588 negligible negligible Effective fishing day for species Total 87 5248 7783 Operational Units* Fleet (n of boats)* Catch (T or kg of the species assessed) Tons Other species caught (names and weight ) Tons Discards (species assessed) Discards (other species caught) Effort (units) MAR 03 G 02 31- PIL 6 47 Anchovy: 3.3 Trachurus spp: 31.98 Scomber spp: 26.13 Sardinella: 49.6 Autres: 68.9 negligible negligible Effective fishing day for species MAR 03 H 02 31- PIL 101 10100 Anchovy: 127.2 Trachurus spp: 542.9 Scomber spp: 581.8 Sardinella: 723.1 Autres : 1441.4 negligible negligible Effective fishing day for species MAR 03 I 02 31-PIL 6 883 Anchovy: 6 Trachurus spp: 25 Scomber spp: 31 Sardinella: 14 Autres : 47 negligible negligible Effective fishing day for species Total 113 11029 3718.691 7
Table 3.1-3: Catches used in the assessment 1990-2014. Spain southern Mediterranean region which includes 95% of total catches in GSA01 YEAR Catch (tons) CPUE Kg/fishing day 1990 6439 921 1991 9599 1328 1992 10826 1308 1993 5782 1095 1994 5220 926 1995 4316 756 1996 3589 612 1997 3263 726 1998 3982 839 1999 5146 1143 2000 8697 1369 2001 6817 1255 2002 5237 1019 2003 7817 1189 2004 3904 792 2005 7066 1272 2006 9376 1478 2007 5683 1116 2008 4329 1069 2009 5896 1313 2010 7164 1270 2011 6065 1139 2012 5431 1112 2013 4456 956 2014 4782 932 2015 5058 977 Average 1990-2015 6001 1074 Morocco (sardine seiners in GSA03) année CAPTURE CPUE 2007 10920 1086 2008 6368 1659 2009 13794 1487 2010 10744 1238 2011 5753 1014 2012 8121 1321 2013 12613 1334 2014 13286 1164 2015 11029 1105 Average (2007-2015) 10292 1268 8
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 Landings (tons) cpue (Kg/fishing day) 3.2 Historical trends Spain 12000 10000 8000 6000 4000 2000 0 Sardine RSM (95%) GSA01 1600 1400 1200 1000 800 600 400 200 0 LANDINGS CPUE Fig. 3.2.1. Trend in sardine landing and CPUEs, years 1990-2015. (Spain) Morocco 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Fig. 3.2.1. Trend in sardine landing 2005-2015. (Morocco) 9
Landings (tons) 16000 14000 12000 10000 8000 6000 4000 2000 0 2007 2008 2009 2010 2011 2012 2013 2014 2015 1800 1600 1400 1200 1000 800 600 400 200 0 CPUE (kg/fishing day) catch (tons) CPUE (kg/day) Fig. 3.2.2. Trend in sardine landing and CPUEs, years 2007-2015. (Morocco) 3.3 Management regulations Regulations in Spanish Mediterranean Sea Regulated by Fishery European regulations REGULATION (EC) Nº 1967/2006 of December 21, 2006, with a more restrictive Spanish regulations. Features gear: Minimum aperture of 14 mm mesh, The height of the purse seine shall not exceed 82 m and the use of purse seines is not allowed at a depth less than 70 percent of the net length, Length net will not exceed more than 300 m except for Alboran Sea which may be up to 450 m. Characteristics of vessels: No less than 9 m long, maximum power 450 hp, only one auxiliary boat and there is a Regulating for its power lights. Fishing areas: prohibited fishing less than 35 m deep, although at a distance of 300 m offshore it is permitted at a lower depth than 50m. There are forbidden fishing areas to keep safe anchovy recruitment. Fishing effort: No fishing on weekend restricted fishing areas and seasonal closures in some regions. Minimum sizes: Minimum legal landing size 11 cm. List of species authorized to be fished by the gear. Margin of 2% of others species. Regulations in Moroccan Mediterranean Sea Features gear: Minimum mesh size of 11 mm. Characteristics of vessels: No less than 3 tjb; only one auxiliary boat. Fishing areas: prohibited fishing less than 0.5 nautical mile (1 nm in some regions). There are forbidden areas to safe sardine recruitment. Fishing effort: No fishing on Friday, restricted fishing areas and seasonal closures in some regions. Minimum sizes: 45 individuals/kg for sardine. List of species authorized to be fished by the gear. Margin of 3% of others species except Boops boops 10%. 10
4 Fisheries independent information 4.1 Acoustic survey Direct methods: acoustics 4.1.1 Brief description of the method Table 4.1-1: Acoustic cruise information. Date MEDIAS: June-July; ECOMED: November-December ACOUMED : 2 surveys/year (April-may; September) (Morocco) Cruise MEDIAS (Spain) ACOUMED (Morocco) R/V Target species Anchovy and sardine Small pelagics Sampling strategy 66 tracks normal to the coast. Inter-transect distance: 4 or 8 nautical miles Inter-transect distance: 5 nautical miles Sampling season Investigated depth range (m) MEDIAS: June-July; ECOMED: November-December ACOUMED: (April-may; September) (Morocco) 30-200 m depth (Spain) 20-400 m depth (Morocco) Echo-sounder Scientific Echo-sounder EK60 equipped with 5 frequencies (18, 38, 70, 120 & 200 khz) Echo-sounder EK60 (38-120-200 khz)- scrutinizing by BI500 Fish sampler Pelagic trawls with 10, 16 & 18 m vertical opening Japanese Pelagic trawl, with gear: type O.B (Al), 1.44 m² (216.4 kg). Cod end mesh size as opening (mm) ESDU (i.e. 1 nautical mile) TS (Target Strength)/species 20 mm Elementary Distance Sampling Unit: 1 nautical mile -72.6 db for anchovy and sardine -72 db for sardine 11
Software used in the post-processing SonarData Echoview, PESMA (Visual Basic) BI500 and Echoview Samples (gear used) Pelagic trawl Japanese Pelagic trawl Biological data obtained Length-weight relationship, age, sex, maturity Length-weight relationship, age, sex, maturity Age slicing method Otolith Maturity ogive used Table 4.1-2: Acoustic results, if available by age or length class 4.1.2 Spatial distribution of the resources Figure 4.1.1. Densities distribution of sardine Spain 2015 12
Figure 4.1.2. Densities distribution of sardine (saison automne 2015). Morocco. 5 Ecological information 5.1 Protected species potentially affected by the fisheries A list of protected species that can be potentially affected by the fishery should be incorporated here. This should also be completed with the potential effect and if available an associated value (e.g. by catch of these species in T) 5.2 Environmental indexes 13
6 Stock Assessment 6.1 {Extended Survivor analysis (XSA)} Ad hoc methods for tuning single species VPA's to fleet catch per unit effort (CPUE) data are sensitive to observation errors in the final year because they make the assumption that the data for that year are exact. In addition, the methods fail to utilize all of the year class strength information contained within the catches taken from a cohort by the tuning fleets. Extended Survivors Analysis (XSA), (Shepherd, 1992,1999), an extension of Survivors Analysis (Doubleday, 1981), is an alternative approach which overcomes these deficiencies. In general, the algorithms used within the ad hoc tuning procedures, exploit the relationship between fishing effort and fishing mortality. XSA focuses on the relationship between catch per unit effort and population abundance, allowing the use of a more complicated model for the relationship between CPUE and year class strength at the youngest ages. (Darby and Flatman, 1994). 6.1.1 Model assumptions Input Parameters Landings time series 2010-2015 (official landings, Spain & Morocco; GSAs 1&3). Catch-at-Length data converted to Catch-at-Age data using cohort slicing. Growth Parameters, IEO 2014. M vector by age using Gislason spreadsheet. Tuning data Moroccan survey ACOUMED from 2012 to 2015 and MEDIAS Spanish survey for the same period. The two surveys were summed up to obtain a total biomass estimate in the area. Main Settings Ages 0 to 3+ (Ag 3 is a Plus Group) Fbar has been set 1-2 R-age was set at 0 and q-at age 3 the number of ages used for the shrinkage mean (Shk.ages) is 1 Number of years used to shrink to the mean (Shk.yrs) was set at 3 Standard error when shrinking the mean (fse) is 0.3 r age q age Shk.ages Shk.yrs fse 0 1 1 3 0.3 6.1.2 Scripts The script has been provided to the sharepoint 6.1.3 Input data and Parameters For analytical models: catch matrix in lengths or ages (see the example below for age). Specify if 14
catch includes discards. Catch numbers at age (in thousands) from 2010-2015 Age class 2010 2011 2012 2013 2014 2015 0 356431 188362 365098 249019 247516 333346 1 195381 114835 186136 201314 347731 224332 2 127424 83812 93394 117543 67272 94549 3+ 51513 48219 40967 48476 48713 42805 6.1.4 Tuning data Abundances index (in thousands). We used the sum of abundance index for GSA01 + GSA03 from 2012-2015. Age class Alboran Alboran Alboran Alboran 0 679287 483982 380146 2038257 1 2208723 3944343 5890783 1441258 2 82705 169178 265521 461615 3+ 30877 9681 22378 37398 6.1.5 Results Fig 6.1.5.1: Age structure of sardine in GSA01&03 15
Fig.6.1.5.2. main results obtained by XSA model Recruitment is different from one year to another with peak in 2013 and 2015. Average fishing mortality in ages 1-2, (Fbar 1-2), has the same trend like recruitment. It fluctuates between 0.3 and 1. Biomass (B) and Spawning Stock Biomass (SSB) shows decrease trend since 2010. 16
6.1.6 Robustness analysis Fig.6.1.6.1: Log catchability residuals for surveys in GSAs 1&3 17
6.1.7 Retrospective analysis, comparison between model runs, sensitivity Retrospective analysis Fig.6.1.7: Retrospective analysis on different stock parameters. 18
6.1.8 Sensitivity analysis Sensitivity analysis on different settings for catchability independent of age qage, shk.ages and shrinkage years Fig.6.1.8.1. Sensitivity analysis on different combinations of r-at-age and q-at-age values 19
Fig.6.1.8.2. Sensitivity analysis on Sensitivity analysis on shrinkage ages shk.ages 20
Fig.6.1.8.3: Sensitivity analysis on different values of shrinkage years The consistency of catches and surveys are given in figure 6.1.8.4. 21
Fig.6.1.8.4.: Consistency of catches and surveys 22
6.1.9 Assessment quality The selection of the suitable parameters for the final XSA run was performed by running sensitivity and retrospective analyses, to ensure the robustness of the final estimates. For instance a value of 1.0 for the shrinkage weight was found inappropriate as it induced great differences from the general pattern. 6.1.10 Reference points Reference points XSA F0.1 0.79 Fcur 0.71 F/F0.1 0.90 E 0.52 The exploitation rate E = Fbar(1-2) / Z is above 0.4 (threshold suggested as a biological reference point for small pelagic (Patterson, 1992). But, F current is below F0.1. The group of experts take this last value of F/F0.1 to decide on the stock status. So, the sardine stock is considered sustainably exploited. 7 Stock predictions 7.1 Short term predictions 7.2 Medium term predictions 7.3 Long term predictions 23
8 Draft scientific advice Based on Indicator Analytic al reference point (name and value) Current value from the analysis (name and value) Empirical reference value (name and value) Trend (time period) Status Fishing mortality Fishing mortality Fishing effort Catch Exploitation F0.1=0.79 Fc=0.71 S Sustainable exploitation Stock abundance Biomass SSB Recruitment Final Diagnosis Sustainably exploited 24
8.1 Explanation of codes Trend categories 1) N - No trend 2) I - Increasing 3) D Decreasing 4) C - Cyclic Stock Status Based on Fishing mortality related indicators 1) N - Not known or uncertain Not much information is available to make a judgment; 2) U - undeveloped or new fishery - Believed to have a significant potential for expansion in total production; 3) S - Sustainable exploitation- fishing mortality or effort below an agreed fishing mortality or effort based Reference Point; 4) IO In Overfishing status fishing mortality or effort above the value of the agreed fishing mortality or effort based Reference Point. An agreed range of overfishing levels is provided; Range of Overfishing levels based on fishery reference points In order to assess the level of overfishing status when F0.1 from a Y/R model is used as LRP, the following operational approach is proposed: If Fc*/F 0.1 is below or equal to 1.33 the stock is in (O L ): Low overfishing If the Fc/F 0.1 is between 1.33 and 1.66 the stock is in (O I ): Intermediate overfishing If the Fc/F 0.1 is equal or above to 1.66 the stock is in (O H ): High overfishing *Fc is current level of F 5) C- Collapsed- no or very few catches; Based on Stock related indicators 1) N - Not known or uncertain: Not much information is available to make a judgment 2) S - Sustainably exploited: Standing stock above an agreed biomass based Reference Point; 3) O - Overexploited: Standing stock below the value of the agreed biomass based Reference Point. An agreed range of overexploited status is provided; Empirical Reference framework for the relative level of stock biomass index Relative low biomass: Values lower than or equal to 33 rd percentile of biomass index in the time series (O L ) 25
Relative intermediate biomass:values falling within this limit and 66 th percentile (O I ) Relative high biomass:values higher than the 66 th percentile (O H ) 4) D Depleted: Standing stock is at lowest historical levels, irrespective of the amount of fishing effort exerted; 5) R Recovering: Biomass are increasing after having been depleted from a previous period; Agreed definitions as per SAC Glossary Overfished (or overexploited) - A stock is considered to be overfished when its abundance is below an agreed biomass based reference target point, like B0.1 or BMSY. To apply this denomination, it should be assumed that the current state of the stock (in biomass) arises from the application of excessive fishing pressure in previous years. This classification is independent of the current level of fishing mortality. Stock subjected to overfishing (or overexploitation) - A stock is subjected to overfishing if the fishing mortality applied to it exceeds the one it can sustainably stand, for a longer period. In other words, the current fishing mortality exceeds the fishing mortality that, if applied during a long period, under stable conditions, would lead the stock abundance to the reference point of the target abundance (either in terms of biomass or numbers) 26