Silent research vessels are not quiet

The aim is to avoid scaring off fish and thus biasing results from stock abundance surveys. However, comparative studies carried out by IMR show that the silent vessel “G.O. Sars” initiates stronger and more prolonged avoidance reactions in herring than a standard vessel.

These results, published by Ona et al. in the journal Acoustical Society of America earlier this week, illustrate the complexity of vessel avoidance behaviour. They also suggest that a stimulus other than noise must be causing the reaction.

This leads Ona and his co-authors to conclude that: “as long as influential candidate stimuli for fish avoidance remain obscure, the ICES goal of establishing a stealth vessel design appears unrealistic.”