The negative ecological impact of trawling for fish at depths of more than 600 metres outweighs the commercial benefits.

Credit: Chris Furlong/Getty

Deep-sea fish are particularly vulnerable to overfishing because populations grow slowly. This has led to calls for a maximum depth for trawling, but it has not been clear what that limit should be. By examining species from scientific surveys of the northeast Atlantic over 35 years, Jo Clarke at the University of Glasgow, UK, and her colleagues found that the proportion of caught fish with no commercial value increased significantly below 600 metres.

Although this evidence supports a 600-metre depth limit in the northeast Atlantic, its relevance to other fishing areas is untested.

Curr. Biol. http://doi.org/66n (2015)

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