Behaviour of Norwegian spring spawning herring in relation to underwater light

Abstract

The Norwegian coastal purse seiners, with shallow nets, have experienced difficulties in catching the herring due to their natura! behaviour being located too deep during day time and toe scattered during night time. Experiments, conducted by FTFI, have shown that scattered congregations of herring may be concentrated by underwater light. When light was switched on underneath the school, the herring immediately rose towards the surface with a speed of approximately 20 m/min. Use of underwater light to manipulate the natural behaviour of herring would increase the efficiency, and consequently the economic benefit for the costal purse seiners.