Working group on the biology and assessment of deep-sea fisheries resources (WGDEEP)

Type Article
Date 2020
Language English
Author(s) ICES
Contributor(s) Lorance PascalORCID
Source ICES Scientific Reports/Rapports scientifiques du CIEM (2618-1371) (ICES), 2020 , Vol. 2 , N. 38 , P. 928pp.
DOI 10.17895/

The ICES working group on biology and assessment of deep-sea fisheries resources (WGDEEP) provides scientific advice on 29 assessment units including stocks of deep-water species and those on shelf areas and in deep waters. Advice is provided every other year for each stock, except for stocks from ICES Division 5.a (Iceland) with annual advice. Due to the Covid 19 disruption, Iceland did not request advice for local stocks. First draft of advice was thus prepared for 13 stocks out of the 29. For the same reason, the meeting was conducted entirely by web-based correspondence. In response most discussions that were not pivotal for advisory work this year were postponed to next year’s meeting. Available time-series for international landings and discards, fishing effort, survey indices and biological information were updated for all stocks and are presented in Sections 4–15 of the report. An important topic that was discussed regarded boarders of species whose distribution extends between two advisory bodies. In WGDEEP the issue is particularly relevant for blackspot seabream stock in ICES Subarea 9. Main conclusions regarding each stock with advice 2020 were: The advice on alfonsinos in 1-10, 12 and 14 refers to two species, Beryx splendens and Beryx decadactylus, that are often not differentiated in the reported landings. In recent years, landings of the two species have been stable. The biomass of blue ling in 5b, 6 and 7 increased in recent years probably reflecting the low fishing mortality for several years. Both fishing mortality and the spawning stock biomass are well within sustainable levels. Black scabbardfish in the Northeast Atlantic showed a slight reduction in abundance in the last two years. Fishing effort on this species have been decreasing probably associated with the ban of trawling in deeper areas. Greater forkbeard in the Northeast Atlantic and adjacent waters is a bycatch species. The combined six survey biomass-index was reduced in two years. Landings have decreased since 2013. Discards are considered high but could not be quantified. The advice on orange roughy in subareas 1–10, 12 and 14 is given for four years. This is an aggregating species and currently there are no evidences that the stock is recovering from overexploited status. Roughhead grenadier in the Northeast Atlantic landings are mainly from Subarea 2 and divisions 5a, and 14b2. Landings from subareas 6 and 7 are potentially misreported. Roughsnout grenadier in subareas 1–10, 12 and 14 landings were zero for more than10 years. Officially reported landings for the period 2006–2008 are considered species misreporting. Roundnose grenadier in 3a is considered to be low level, which can be partly due to exceptionally high landings in the past, and present low levels of recruitment. Roundnose grenadier in subareas 6–7 and divisions 5.b and 12.b landings have been at a very low level in last eight years. Recent survey biomass index is at low level. Blackspot seabream in Subarea 10 landings have been stable for the last four years. Biomass index fluctuates but has been at relatively high level in recent years. Blackspot seabream in Subareas 6, 7 and 8 abundance strongly declined in the mid-1970s, and is considered to be seriously depleted. Landings are mainly by-catches and surveys show persistent low occurrence of the species. Blackspot seabream in Subarea 9 has been assessed based on biomass index from a target fishery operating in the Strait of Gibraltar, mostly operating out of Subarea 9. Currently the index is at very low level. Tusk in Subarea 6b landings have strongly declined since 2000. The commercial biomass index is at a low but stable level. Potential causes for the decline are not fully understood. The assessment unit of ling in area 5b is planned for ICES Benchmark in 2021.

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