Scientia Marina, Vol 75, No 2 (2011)

Ecosystem structure and trophic analysis of Angolan fishery landings


https://doi.org/10.3989/scimar.2011.75n2309

Ronaldo Angelini
Departamento de Engenharia Civil, Universidade Federal do Rio Grande do Norte - Marine Research Institute and Zoology Department, University of Cape Town , Brazil

Filomena Vaz-Velho
Instituto Nacional de Investigação Pesqueira , Angola

Abstract


Information on the mean trophic level of fishery landings in Angola and the output from a preliminary Ecopath with Ecosim (EwE) model were used to examine the dynamics of the Angolan marine ecosystem. Results were compared with the nearby Namibian and South African ecosystems, which share some of the exploited fish populations. The results show that: (i) The mean trophic level of Angola’s fish landings has not decreased over the years; (ii) There are significant correlations between the landings of Angola, Namibia and South Africa; (iii) The ecosystem attributes calculated by the EwE models for the three ecosystems were similar, and the main differences were related to the magnitude of flows and biomass; (iv) The similarity among ecosystem trends for Namibia, South Africa and Angola re-emphasizes the need to continue collaborative regional studies on the fish stocks and their ecosystems. To improve the Angolan model it is necessary to gain a better understanding of plankton dynamics because plankton are essential for Sardinella spp. An expanded analysis of the gut contents of the fish species occupying Angola’s coastline is also necessary.

Keywords


Ecopath with Ecosim; fishery management; marine ecosystem; Sardinella; trophic level

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