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Report of the Working Group on Elasmobranch Fishes (WGEF) | 1091

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Report of the Working Group on Elasmobranch Fishes (WGEF) | 1091 1090 | ICES WGEF Report 2018 Annex 8: Report in response to the French request for updated advice on Undulate ray (Raja undulata) in Divisions 7.d–e and 8.a–b for 2018 Contents • Report on the French request for updated advice on Undulate ray (Raja undulata) in Divisions 7.d-e and 8.a-b for 2018 • Skates and rays in the Celtic Seas (ICES subareas 6 and 7 (except Division 7.d)) • Skates in the Bay of Biscay and Iberian Waters (ICES Subarea 8 and Division 9.a) • Reviewers’ comments NB: Section 18: Skates and rays in the Celtic Seas (ICES subareas 6 and 7 (except Division 7.d)) and Section 19: Skates in the Bay of Biscay and Ibe- rian Waters (ICES Subarea 8 and Division 9.a) of this report were released again in connection with the release of the single-stock advice on fishing opportunities for elasmobranch stocks in October 2018. Please see these sections (pp. 452-585) for the most up to date information. Report of the Working Group on Elasmobranch Fishes (WGEF) | 1091 ToR k)Special request from France to revise the advice provided in 2016 on fishing opportunities for 2018 for the stocks of undulate ray (Raja undulata) in 7.de and in 8.ab. Introduction WGEF had the following ToR: Address the special request from France to revise the advice provided in 2016 on fish- ing opportunities for 2018 for the stocks of undulate ray (Raja undulata) in 7.de and in 8.ab by: i) validating new data provided by France from: o industry self-sampling programme o observer programme ii) update the catch advice for 2018 based on the results of the data validation, the STECF report on survivability and updated assessment. Prepare a draft advice docu- ment for these two stocks. Background on undulate ray Regulation during the past decade Landings of undulate ray from these two stocks were banned for six years from 2009 to 2014 as undulate ray was included in the EU list of prohibited species following alarming signal from the UK-BTS Q3 surveys where the species was not caught during three consecutive years. Except in Division 7.d, where the French CGFS survey pro- vides a reliable indicator, surveys do not provide reliable biomass trends of the two stocks of undulate ray. In the Bay of Biscay, the distribution of the species is mostly inshore of the area sampled by the EVHOE survey, which does not cover water shal- lower than 25-30 m. In Division 7.e, only small numbers are caught in the UK-BTS sur- vey. Since 2015, small bycatch TAC have been allowed in Division 7.e, 7.b and 8.ab. Background studies Data and analyses on undulate ray were presented in previous years to WGEF. The working document from Leblanc et al. (2014 WD) showed that R. undulata was the main skate species caught in the Norman-Breton Gulf. The species was shown to be domi- nant in coastal waters; although it occurs in almost all the English Channel its distribu- tion appears to be concentrated in the central region of the English Channel. This work- ing document also shown that the decrease in catch of skates and rays in the French fisheries of the Gulf Normand-Breton, may have been 300 tonnes. In the Bay of Biscay a tagging survey was carried out from the end of 2011 to mid-2014 in the Bay of Biscay with the partnership of the fishing industry (Biais et al., 2014, WD). It showed that the undulate ray can be found all along the French coast from the Loire estuary to the Spanish boarder, forming several isolated units, the more important be- ing likely in the central part of the Bay of Biscay (Pertuis Charentais – Gironde area). Even within this limited area, the population is structured in sub-units with a low ex- change rate between them. The biomass of undulate rays longer than 65 cm in the inner Gironde estuary was estimated to be in the range from 51 to 70 t during the 2013-2014 1092 | ICES WGEF Report 2018 winter (95% confidence interval is 30-124 t). The Gironde estuary being only a small proportion of the area where the species occurs in the Bay of Biscay. Further, tagging studies in Division 7.de indicated high site fidelity (Stéphan et al., 2014 WD; Figure 18.40). In the Normano-Breton Gulf, 1488 R. undulata were tagged with a 5% (n=77) recapture rate. All the skates tagged in a region were recaptured in the same region, and distance travelled was short (<80 km). In 2015, WGEF carried out preliminary estimates of discards of undulate ray in the English Channel for the year 2013, when the species was on the prohibited list. The estimated discards in 2013 amounted to 875 tonnes and 66 tonnes respectively in 7.e and 7.d for trawl metiers. The total estimated discards in 7.de by all métiers (towed and passive) was estimated to 1778 t in 2013. Treatment of the special request by WGEF A working document based on analyses of the French self-sampling progamme ap- plied to vessels allowed to land undulate ray and on-board observers data collected under the EU-DCmap in 2015-2017 was presented (Gadenne and Biseau, 2018, WD; Section 1.2). In addition an analysis of landings and discards from 2009 to 2017 of undulate ray and five other ray species (blonde ray, cuckoo ray spotted ray, small-eyed ray and thorn- back ray) caught in French fisheries of Divisions 7.de and 8.ab was carried out. Survey data in Division 7.d were also used to compare abundance of the undulate ray to thorn- back and blonde rays. Estimating French discards of undulate ray from the self-sampling programme This analysis aims to provide new data to support the update of the ICES advice re- garding the undulate ray (Raja undulata), for two stocks occurring in French coastal areas where they are caught by French fleets: - rju.27.8.ab: undulate ray in divisions 8.a–b (northern and central Bay of Biscay), - rju.27.7.de: undulate ray in divisions 7.d and 7.e (English Channel). An advice was issued in 2016 based on recent landing, which were very strongly con- strained by the total allowable catch (TAC), arbitrarily set in 2015. Table 1. History of TAC for undulate ray stocks in three areas. Year TAC for EC waters of TAC for EC waters of TAC for EC waters of 7.e 7.d 8.abc 2009 landing ban landing ban landing ban 2014 0 t 0 t 0 t 2015 41 t 8 t 9 t 2016 41 t 9 t 16 t 2017 65 t 14 t 19 t 2018 65 t 14 t 19 t Report of the Working Group on Elasmobranch Fishes (WGEF) | 1093 This study (Gadenne and Biseau, 2018, WD) provides new data to support the update of the ICES advice regarding undulate ray stocks in Divisions 7.de and 8.ab. Catches (landings and discards) of undulate ray by ICES divisions in 2016 and 2017 are esti- mated using the landings of all species as an auxiliary variable. Data include (Gadenne and Biseau, 2018, WD) official landings (estimated from a com- bination of logbooks and other compulsory reporting from fishers, fish auction market sales and other data, e.g. VMS), landings and discards sampling from the French on- board observations program, carried in application of the EU-DCmap program from the French fishery information data facility (SIH – Système d’Informations Halieu- tiques), and the undulate ray specific self-sampling program aiming at the collection of data by fishers on the level of bycatch on undulate ray. The self-sampling program involves all the vessels that were allowed to land undulate ray in 2016 and 2017 from Divisions 7.de and 8.ab according to EC 2015/960 and several management measures to regulate the bycatch and the landings of undulate ray (Gadenne, 2017). Table 2. Overview of data used Official land- On-board observations Specific self-sampling ings data data data Year 2016 2017 2016 2017 2016 2017 Landing/Discard LAN LAN LAN (DIS) LAN (DIS) LAN & DIS LAN & DIS Vessels number 185 126 56 59 Trips number 2540 213 (33) 171 (28) 1236 1971 Fishing trips 430 (66) 318 (69) 5190 6860 All trips being sampled, the number of samples in this program and the spatio-tem- poral coverage are much larger than the EU-DCmap onboard sampling program (Table 2). In 2016, only landings data (59 tonnes for divisions 7.de) were used by ICES to pro- vide the fishing opportunities for 2017 and 2018, after the 2010-2015 ban. In the working document (Gadenne and Biseau, 2018, WD) the description of quanti- tative and spatial coverage of each used dataset is first detailed. Secondly, a method to validate self-sampling data is presented to consolidate the use of the self-sampling da- taset. Finally, different methods were used to raise data and to estimate total catches (discards and landings) of undulate ray. Methods Because participating in the self-sampling program allows the vessel to land undulate ray with a limit of 150 kg per day/trip, it was considered that trips for which landing of undulate ray was allowed should be excluded from the on-board observations data set when raising discards of undulate ray as the fishing strategy might be impacted by having a fishing license (Gadenne and Biseau, 2018, WD).
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