engleski

Bottlenose dolphins and fisheries – how much fish do they really take?

The bottlenose dolphin is the only cetacean species with confirmed resident populations in the Croatian Adriatic. As they inhabit inshore waters, interactions with humans are possible, and one aspect of the interaction is competition for food resources. We suggested that bottlenose dolphins feed mainly on demersal fish which is also exploited by fisheries, but that the dolphin food intake of individual fish species is not commercially significant. We examined stomach contents of bottlenose dolphins stranded along Croatian coast between 1990 and 2005, and analysed hard food remains ascribing it to species or the lowest possible taxon. Diet composition was estimated according to frequency and calculated weight of prey species. Annual consumption of prey species important in fisheries was estimated, and using a simple model estimation of fish stocks for a 10 year period was made, used to asess the quantity of fish removal by dolphins and significance for the fisheries. We concluded that firstly, bottlenose dolphins in the Eastern Adriatic besides fish also used cephalopodes as an important food source, and secondly, that the present bottlenose dolphin population does not have a significant effect on economically important fish species abundance. The presentation of these results to the fishermen could help in easier implementation of some measures for the bottlenose dolphin protection.

bottlenose dolphin

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