engleski

Comprehensive morphometric analysis of wild and farmed gilthead seabream (Sparus aurata, L. 1758) in the eastern Adriatic Sea

The expansion of modern aquaculture industry of gilthead sea bream Sparus aurata and European sea bass Dicentrarchus labrax introduced new impacts on biota in form of escape of domesticated individuals from farms and their dispersal into wild fish populations. Interaction of wild and farmed fish has led to scenarios with negative ecological and genetic consequences such as increased predation and competition for specific habitat and food resources and unfavourable gene flows between reared and wild individuals. Escape events in the last decade significantly increased the biomass contribution of escapees to local habitats, and thus fisheries landings across Mediterranean, which led to intentional mislabelling of farmed fish as wild on the markets because of the difficulty to distinguish them. In this study, we evaluate possible ecological impacts of escaped farmed gilthead sea bream in the eastern Adriatic Sea using morphometric features of body shape, which proved to be a fast, accurate and cost-effective diagnostic tool for rapid assessment in the field. A combination of classical measurement scheme, truss network system, geometric morphometric and condition factor index is used in order to trace possible escapees among wild populations through investigation of morphological similarity/dissimilarity between eleven wild and three farmed groups of different stock origin. We discuss the morphometric results of these three different methods used for population discrimination in order to provide better guidelines for fish origin assessment and quantification of escapees in wild. The proposed tool is highly important for aquaculture industry (recapture strategy) as well for environmental managers (genetic diversity protection of native populations).

Geometric morphometrics; Sparus aurata; morphology; aquaculture

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