Evaluation of selectivity and bycatch mitigation measures using bioeconomic modelling. The cases of Madagascar and French Guiana shrimp fisheries

Abstract

-Tropical shrimp fisheries are characterized by various interactions with their natural environment and with other fisheries. These latter interactions can be explained by the high quantity of bycatch taken by industrial trawler fleets, which has a significant impact on fish populations associated with shrimps and thus also on finfish fisheries. Bycatch also includes emblematic species, which are subject to strict conservation measures decided by the international community. It seems important to identify and assess the biological and economic consequences of different mitigation measures (increase of mesh size, turtle excluder devices and bycatch reducing devices). This communication is based on case studies undertaken on the Indian white prawn (Fenneropenaeus indicus) and speckled shrimp (Metapenaeus monoceros) fisheries in Madagascar and on the brown shrimp (Farfantepenaeus subtilis) and pink spotted shrimp (Farfantepenaeus brasiliensis) fishery in French Guiana. A review of the impacts of these fisheries on resources and ecosystems is made and some results of experiments on mitigation devices given. Finally, the results of simulations obtained using a multi-species, multi-fleet, age-structured bioeconomic model, including modifications of catchability and costs related to the adoption of these devices, is presented and discussed.

Restoring the ecosystem creates wealth. The case of the Northern coast of Tunisia’s deep-water rose shrimp trawl fishery

“…The bioeconomic model was constructed by adapting to the northern Tunisian shrimp fishery existing models, designed for the shrimp fisheries of Madagascar and French Guiana (Chaboud, 2008;Chaboud et al, 2008;Chaboud and Thébaud, 2009;Chaboud and Vendeville, 2011).…”

“…Bioeconomic models were used from an early stage in shrimp fisheries such as those in the Gulf of Mexico (Grant and Griffin, 1979;Grant et al, 1981;Blomo et al, 1982), in Northern Australia (Ye et al, 2005;Clark and Kirkwood, 1979;Kirkwood, 1984), in French Guiana (Gilly and Cochet, 1987;Dintheer et al, 1991;Béné, 1997;Chaboud et al, 2008;Chaboud and Thébaud, 2009;Chaboud and Vendeville, 2011) and in Madagascar (Chaboud, 2000;Chaboud et al 2008). The bioeconomic approach was also applied in artisanal and multi specific trawl fisheries in the Mediterranean (Lleonart et al, 2003;Merino et al, 2007aMerino et al, ,b, 2015Maynou et al, 2013;Russo et al, 2014).…”

Assessing impacts of bycatch policies and fishers’ heterogeneous information on food webs and fishery sustainability

“…The three bioeconomic factors we introduced in our network model are well-studied in the bioeconomic literature but only for a handful of species in that ecosystem [49][50][51][52]. Thus, our work contributes to the bioeconomic literature by considering the entire ecological network to which the target and bycatch species belong.…”