Comparison of approaches for incorporating depredation on fisheries catches into Ecopath

Ecosystem-based approaches are increasingly used in fisheries management to account for the direct trophic impacts of fish population harvesting. However, fisheries can also indirectly alter ecosystem structure and functioning, for instance via the provision of new feeding opportunities to marine predators. For instance, marine depredation, where predators feed on fishery catches on fishing gear, is a behaviour developed by many marine species globally. This behaviour can modify both the ecological role of predators and fisheries performance. Yet, these ecosystem-wide effects of depredation are rarely considered holistically. In this study, we explored different ways of incorporating depredation into an Ecopath trophic model. We assessed, through a subantarctic case study, how three alternative model structures can account for depredation effects on fishery catches, predator and non-commercial prey populations, as well as target fish stocks. While none adequately addresses all facets of depredation, the alternative models can to some extent capture how depredation can lead to increased fishing pressure on stocks. As structural specificities of Ecopath prevented us from representing other depredation effects such as provisioning effects for predator populations, we conclude this study with a set of guidance to effectively capture the complex effects of depredation in marine ecosystems and fisheries models.

Keyword(s)

Crozet, depredation, Ecopath, ecosystem model, Kerguelen, marine predators, model structure

Full Text

FilePagesSizeAccess
Publisher's official version
15975 Ko
Supplementary data
461 Mo
How to cite
Clavareau Lyndsay, Marzloff Martin, Trenkel Verena, Bulman Catherine M, Gourguet Sophie, Le Gallic Bertrand, Hernvann Pierre-Yves, Péron Clara, Gasco Nicolas, Faure Johanna, Tixier Paul (2020). Comparison of approaches for incorporating depredation on fisheries catches into Ecopath. Ices Journal Of Marine Science. 77 (7-8). 3153-3167. https://doi.org/10.1093/icesjms/fsaa219, https://archimer.ifremer.fr/doc/00661/77317/

Copy this text