Human are altering key behaviours of wild-living animals, including those related to foraging, reproduction and survival. When exposed to potentially lethal human actions, such as hunting or fishing, fish and wildlife are expected to behaviourally respond by becoming shyer and learning when to be cautious.

This study used data collected in temperate rocky reefs to provide evidence of spearfishing-induced behavioural changes in five coastal fish taxa, exposed to different levels of spearfishing exploitation, inside and outside of Marine Protected Areas, by using flight initiation distance (FID) as a proxy of predator avoidance.

The obtained results show an increase of mean and size effects of FID when the observer was equipped with a speargun. The authors underline that such effects were more evident outside MPAs where spearfishing was allowed.

The authors highlight that the results of the study demonstrate the ability of fish to develop fine tuned antipredator responses and to recognize the risks pose by spearfishers as human predators.

It is concluded that the study provides a comprehensive assessment of how spearfishing modulates fish anti-human-predator behaviour in the wild, demonstrating that fishes are able to discriminate between snorkelers with or without a speargun.

Sbragaglia V, Morroni L, Bramanti L, Weitzmann B, Arlinghaus R, Azzurro E (2018) Spearfishing modulates flight initiation distance of fishes: the effects of protection, individual size, and bearing a speargun. – ICES Journal of Marine Science doi:10.1093/icesjms/fsy059.