The use of a high definition (HD) underwater camera to observe the behaviour of yellowtail flounder (Limanda ferruginea) in the mouth of a commercial bottom trawl

Abstract

Underwater camera systems are often used to gain a better understanding of fish behaviour in relation to fishing gear prior to conducting gear modifications. Although the use of camera systems enables researchers to identify roundfish, their use has been unreliable in identifying flatfish to the species level. The high-definition self-contained underwater camera system developed in this study enabled flatfish to be identified to the species level with a high degree of certainty, something not previously capable of traditional camera systems. In this study, in situ underwater camera observations were conducted to observe and quantify the relationship between yellowtail flounder (Limanda ferruginea ) behaviour and demersal trawls. A series of novel statistical tests were applied to evaluate hypotheses related to orientation, behaviour, residence time, and fate of an individual. These behavioural observations will form the basis for future trawl designs that incorporate improvements in catch efficiency and may reduce ecological impact.