A cost-benefit analysis of improving trawl selectivity in the case of discards: The Nephrops norvegicus fishery in the Bay of Biscay

Type Article
Date 2008-07
Language English
Author(s) Macher ClaireORCID1, 2, Guyader Olivier1, Talidec CatherineORCID3, Bertignac MichelORCID4
Affiliation(s) 1 : IFREMER, Ctr Brest, Dept Econ Maritime, F-29280 Plouzane, France.
2 : Ctr Droit & Econ Mer, UBO, F-29238 Brest 3, France.
3 : IFREMER, Stn Lorient, Dept Sci & Technol Halieut, Lab Ressources Halieut, F-56100 Lorient, France.
4 : IFREMER, Ctr Brest, Dept Sci & Technol Halieut, Lab Biol Pecheries, F-29280 Plouzane, France.
Source Fisheries Research (0165-7836) (Elsevier), 2008-07 , Vol. 92 , N. 1 , P. 76-89
DOI 10.1016/j.fishres.2007.12.021
WOS© Times Cited 31
Keyword(s) Fisheries management, Discards, Selectivity, Cost benefit analysis, Bio economic simulations, Nephrops norvegicus
Abstract The Nephrops trawl fishery is one of the most important fisheries in the Bay of Biscay. The fishery management essentially relies on conservation measures, a total at I owed catch (TAC) for Nephrops together with a mini mum landing size (MLS) and minimum trawl mesh size (70 mm stretched mesh). These measures have failed to prevent high discard levels of many species that characterize the fishery. Nephrops trawlers thus discard about half of their Nephrops catches in numbers (a third in weight) of which only 30% survive. Nephrops discards mainly occur in younger Nephrops age groups below the MLS. This is a waste for the already overexploited Nephrops stock as well as for the fleet. Based on a bio-economic simulation model, the paper analyses the consequences of several scenarios of improving Nephrops selectivity. The potential impacts of these scenarios on Nephrops biomass, landings, discards and economic indicators (e.g. rent) are examined and a cost-benefit analysis of each scenario is carried out. We show that a better exploitation pattern would benefit fisheries that have high level of discards. Reducing non-commercial Nephrops discards leads to positive net present values of rent with better value realized from the production potential and limited short-term losses for the fishing units. By taking account of the economic dynamics of increasing effort however, we show that selectivity measures are insufficient. Regulating access to the fishery is also required to ensure the sustainability of the fishery and a better exploitation of the production potential. (C) 2008 Elsevier B.V. All rights reserved.
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