Quantification and representation of potential spatial interactions in the southern Benguela ecosystem

Authored by L Pecquerie, P Freon, LJ Shannon, L Drapeau

Date Published: 2004

DOI: 10.2989/18142320409504054

Sponsors: Institut de Recherche pour le Développement (IRD)

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

This work explores the potential spatial interactions between 13 key commercial species of the southern Benguela ecosystem: sardine Sardinops sagax, anchovy Engraulis encrasicolus, round herring Etrumeus whiteheadi, horse mackerel Trachurus trachurus capensis, chub mackerel Scomber japonicus, chokka squid Loligo vulgaris reynaudii, kingklip Genypterus capensis, Cape hake Merluccius spp., silver kob Argyrosomus inodorus, snoek Thyrsites atun, albacore Thunnus alalunga, bigeye tuna Thunnus obesus and yellowfin tuna Thunnus albacares. It is based on distribution maps per species after combining available commercial and research databases. The resulting 78 pairs of potential interactions are quantified using three indices: the overlap in area, the overlap in biomass and the weighted kappa index. From additional information on the diet of the different species and trophic models, the main trophic interactions (predation or competition) were identified and mapped. The results are discussed with regard to methodological limitations, habitat selection, fish assemblages, the need for spatial resolution of trophic models and the ecosystem approach to fishery management.

Tags

Marine protected areas Life-history Individual-based model Fisheries management Trophic interactions African west-coast Anchovy Acoustic surveys Demersal fish assemblages Cape