Changes and trends in the overexploited fish assemblages of two fishing grounds of the Northwest Atlantic

An ecosystem approach is widely recognized as desirable for fisheries management. A key element is the development of indicators for the assessment of ecosystem status. We evaluated the status of two, exploited marine ecosystems, Southern Grand Banks of Newfoundland and Flemish Cap, using a multivariate analysis and a suit of ecological indicators. We used data obtained from two multispecies bottom trawl surveys performed by the Spanish Administration in the Southern Grand Banks (3NO survey) from 2002 to 2014, and the EU in the Flemish Cap (3M survey) from 1991 to 2014. We studied the dynamic of major demersal fish assemblages (38-300, 301-600, and 601-1460 m depth in 3NO; 129-250, 251-600, and 601-1460 min 3M). Temporal changes and trends in fish assemblages' structure were tested using a non-metric multidimensional scaling and four indicators (mean trophic level, species evenness, species diversity, and species richness). This study revealed the importance of calculating indicators in each assemblage and the usefulness of indices to compare areas and periods under different fishing pressure.