Influence of aquaculture waste on fatty acid profiles and gonad maturation of wild fish aggregations at fish farms.

Wild fish belonging to four species belonging to different trophic groups were captured at three distances from fish farm facilities: long distance (>5 Km), medium distance (1.5 Km) and close to sea-cages. Flesh, brain, liver and gonads were sampled for fatty acid analysis. Fish aggregated near sea-cages showed accumulation of fatty acids of vegetable origin in the studied tissues, due to surplus feed consumption or via predation of fish that consumed the feed. Gonads accumulated vegetable fatty acids in different manner in the different species, and the species least and most influenced by fish-feeds were selected for gonad histological examination. Results showed an acceleration of the final stages of the oocyte development in fish aggregated near fish farms compared to fish captured at long distance. Differences in oocyte development were more acute in the species which incorporated higher quantities of vegetable fatty acids.