Monitoring of discarding and retention by trawl fisheries in Western Waters and the Irish Sea in relation to stock assessment and technical measures

• Main Authors: Allen, M. (Michelle), Araujo-Fernández, M.H. (María Hortensia), Armstrong, M. (Mike), Briggs, R. (Richard), Caslake, R. (Richard), Díez, G. (Guzmán), Findlay, M. (Malcom), Godden, N. (Nigel), Hewer, A. (Alison), Hugues-Dit-Ciles, E. (Emily), Kingston, A. (Allen), Lart, W. (William), Lucio, P. (Paulino), Pérez-Contreras, M.N. (María Nélida), Pawson, M. (Mike), Quincoces, I. (Iñaki), Reese, R.A. (Allan), Santurtún, M. (Marina), Schön, P.J. (Pieter Jan), Scott, R. (Robert), Searle, A. (Allen), Senior, R. (Rebbecca)
• Format: Report
• Language: English
• Published: Centro Oceanográfico de Vigo
• Subjects: Dermersal fisheries; Fish discards; By catch; Trash fish; Marine fish; Commercial species; Fishery surveys; Fishery stock assessment; Fishery resources; Fishery data; Fishery management; Fishery statistics; Fish catch statistics; Fishery economics; Fishing gear; Fishing technology; Marine ecology; Irish Sea; Celtic Sea; Bay of Biscay; North East Atlantic; Baka; North Atlantic; Northeast Atlantic
• Online Access: http://hdl.handle.net/10508/9089

Westem Waters fisheries face major challenges in relation to the depleted state of the fishery resources and in implementing the adjustments required to bring exploitation of these resources on to a more sustainable basis. Fisheries assessments, as carried out by ICES working groups, use data from market sampling of the landed catch, reported landings and effort figures and also research vessel data to assess the state of fish stocks and to produce short term forecasts for setting Total Allowable Catches. Since the discards may constitute a significant source of extra mortality in some fisheries there is clearly a requirement to adequately describe the levels of discarded fish in order to improve stock assessment and the likelihood of sustainability. In deciding a strategy for improved sustainability there is also a requirement to understand the factors motivating the fishers to target and retain, or discard, fish of a given species and to relate this to the current management and market situation. This, and stock assessment information, could be used to guide research into the most appropriate technology and measures to reduce discarding and hence place the harvesting of these stocks on a more sustainable basis. The project studied the pattem of discarding and retention, using an onboard observer programme, in the main demersal trawl fisheries of the participating nations' in Westem Waters (ICES Divisions VIa,b VIIa,b,c,e(western part), f,g,h and k and from VIIIa,b,c,d and IXa) and describes the use of these data in ICES stock assessments. It assessed the feasibility of using these data to understand the economic aspects of discarding and retention, to assess the impact of technical measures and investigated the effects of trawling on ecosystems. Data on discarded megrim from Spanish Baka trawlers were used in the assessment of the Northem Stock of this species at the ICES Southem Shelf Demersal Working Group. These results show that including discard data in the assessment improved the description of the ...