Working Group on Elasmobranch Fishes (WGEF).

Type Article
Date 2019
Language English
Author(s) ICES
Contributor(s) Baulier Loic, Biais Gerard, Lorance PascalORCID
Source ICES Scientific Reports/Rapports scientifiques du CIEM (2618-1371) (ICES), 2019 , Vol. 1 , N. 25 , P. 964p.
DOI 10.17895/

ICES WGEF meets annually, with advice for a subset of stocks drafted in alternating years. Work in 2019 focused on those stocks for which it was an advisory year: (i) skate stocks in the North Sea ecoregion, the Azores and MAR; (ii) catsharks (Scyliorhinidae) in the Greater North Sea, Celtic Seas and Bay of Biscay and Iberian Coast ecoregions; (iii) smooth-hounds in the Northeast Atlantic; and (iv) tope in the Northeast Atlantic). The following widely-distributed shark stocks were also assessed: (i) Portuguese dogfish; (ii) Leafscale gulper shark; (iii) Kitefin shark; (iv) Porbeagle, and the following species that are on the prohibited species list: (v) angel shark, (vi) basking shark and (vii) white skate. Although all stocks were assessed, advice was not given for the stocks listed below following correspondence with DG-Mare.  Common skate complex (Blue skate (Dipturus batis) and flapper skate (Dipturus intermedius) in Subarea 4 and Division 3.a (North Sea, Skagerrak and Kattegat)  Black-mouth dogfish (Galeus melastomus) in subareas 6 and 7 (West of Scotland, southern Celtic Seas, and English Channel)  Black-mouth dogfish (Galeus melastomus) in Subarea 8 and Division 9.a (Bay of Biscay and Atlantic Iberian waters)  Lesser-spotted dogfish (Scyliorhinus canicula) in divisions 8.a-b and 8.d (Bay of Biscay)  Lesser-spotted dogfish (Scyliorhinus canicula) in divisions 8.c and 9.a (Cantabrian Sea and Atlantic Iberian waters)  Greater-spotted dogfish (Scyliorhinus stellaris) in subareas 6 and 7 (West of Scotland, southern Celtic Sea, and the English Channel) WGEF had a Term of Reference on further developing a proposed joint meeting with ICCAT for the assessment of the porbeagle (Lamna nasus). However, ICCAT has had a change in their planning of the stock assessments and will now be concentrating on the shortfin mako (Isurus oxyrinchus) in 2019. This change means that the joint porbeagle assessment has been postponed, likely until 2020. The ToR for this meeting will be further developed once a date has been set. One of the important issues for this meeting will be which models and input data will be used. Analyses done by WGEF include a SPiCT model and new tagging and survey data from France. One of the recurring issues at the WGEF meetings is the data call and availability of data. The WGEF data are not submitted to InterCatch, but the group has developed a landings/discard spreadsheet and table in which the data are arranged for ease of assessments. However, there are continuing issues with how the data call is interpreted leading to non-uniform data sets. This results in the WGEF data coordinator, group members and the data deliverers investing time to create a coherent database for the assessments. During the 2019 meeting, the entire process and the use of the spreadsheet table were discussed at length and solutions were suggested. Specifically to ensure that the experience from the 2019 discussions are used to improve the data call and revisit the overall landings table (2005–2018) created at WGEF 2019 and create R codes for the inclusion of new landings data; create a landings data file prior to the WGEF 2020 meeting that is not changed during the meeting. The group recommended to hold a meeting on the landings/ discard table used by WGEF with a small dedicated group prior to the 2020 data call. During the assessments a number of discrepancies in the survey data-base were highlighted and the choice of surveys and survey data to be used for each stock assessment was discussed. As this is fundamental to the work of WGEF, it was decided that there should be a workshop on the use of surveys in the stock assessments prior to the 2020 WGEF meeting. This is a large task and will be staggered, with a meeting in 2020 for the stocks to be assessed in that year, and another one in 2021 for the other stocks. WGEF has prepared a recommendation for a stand-alone workshop on this issue with survey experts, either just prior to the regular WGEF meeting or earlier in the year. The use of discard data in the assessments has been addressed at a workshop in February 2019 – WKSHARK5 (ICES, 2019 in prep) and again at the 2019 WGEF meeting. During WKSHARK5 a trial was carried out to include discard information in the advisory process (ICES, 2019 in prep). The landings information in the advice sheet for thornback ray North Sea stock for 2017 was updated with discard information and the assessment was recalculated. This resulted in a 30% decrease in landings advice. During the exercise, it was noted that not all countries had supplied discard data for the period covered (2009–2016) so this result was considered only as an indication. At the WGEF meeting, it was decided to include the discard information for the 2019 stock assessments according to the example carried out at WKSHARK5. Unfortunately, an overview of the available discard data was made and it was noted that there were a high number of discrepancies between years and data were also missing. It was decided by the group that the discard data available to the group are not of sufficient quality to use in the assessments at this stage. Moreover, the issues exposed by both WKSHARK5 and WGEF are too complex to be solved during a workshop or working group meeting and will require a concerted effort to solve. WGEF has formulated a recommendation for ICES to initiate a dialogue with DG Mare to explore the possibility of funding to support a project to address the serious issues surrounding the collection and registration of discard data, as well as how to include survivability, in order for the data to be used in future stock assessments.. The group looked at further developing MSY proxy reference points relevant for elasmobranchs and to exploring/applying MSY Proxies analyses for selected stocks. For this, work done in the WKLIFE VIII was presented. The Workshop on the Development of Quantitative Assessment Methodologies based on Life-history traits, exploitation characteristics, and other relevant parameters for stocks in categories 3–6 (WKLIFE VIII) met in Lisbon, Portugal, 8–12 October 2018, to further develop methods for stock assessment and catch advice for stocks in categories 3–6. The resulting ICES report includes a section specifically dedicated to an elasmobranch life history (ICES WKLIFE VIII, 2018; Section 5, Annex 1). The performance of advice rules using lengthbased indicators and MSY proxy reference points to manage elasmobranch fisheries were investigated within an MSE framework. An operating model was built based on the cuckoo ray life history from the Irish Sea, with alternative scenarios for size of capture relative to size of maturity and advice rules. Advice rules based on the length-based indicator mean length are sensitive to the value of length at capture Lc, the assumption of spawning-stock recruitment relationship, misspecification of the reference point LF=M, frequency of assessment and data quality. This is further discussed in Section 26. The Working Group dealt with a special request from NEAFC-OSPAR for advice on deep sea sharks, rays and chimaeras, following a process agreed by WGEF experts, clients and ACOM and addressed the following points: (i) screening of data received from ICES Member States on occurrence of deep water sharks, skates and chimaeras on the extended list provided in the request; (ii) look at the part of request pertaining to the bycatch and mitigation measures and allocate work for the rest of the request; (iii) formulate ToRs for a WKSHARK6 meeting to be held in early 2020. A questionnaire has been developed to send to experts to gather information on existing management measures, legislation and relevant surveys in order to decide how future management should be. It was asked if measures should be specific to fleet, species/taxa or to habitats, and what human induced pressures could impact the life-cycle of the species. The results will be presented at the 2020 WKSHARK6 workshop. Data on Life-history traits, incl. aggregating behavior, information from literature is being compiled. TACMAN information can be summarized to address the ToR on bycatch mitigation One leader per country will be identified to complete surveys data call and review the data The WKSHARK6 Workshop on the OSPAR and NEAFC joint advice request to generate species distribution maps for listed deep sea shark species and provide scientific support for ICES advice on bycatch management options has been planned for 20–24 January 2020 in Galway, Ireland.

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