Fish beahaviour studies as an aid to cod and haddock longline hook design.

The evolution of the fishing hook to the present form has been very gradual, and only slight alterations have been made since metals became available as material for hooks. This may indicate that the form is close to optimal, or that too little emphasize has been put on research concerning the catching power of the hook. The performance of sport fishing hooks is regularly tested both with regard to gear and fish behaviour. It is therefore probable thAt these hooks are close to optimal for their pourpose~ The various long line hooks have on the other hand mainly been altered to facilitate baiting and gear handling. Their passive role in the hooking proces obviously requires other properties than what is called for in most sport fishing situations, yet the forms are very similar or identical. In the present paper behavioural sequence analysis is used to generate ideas for better cod and haddock long line hook forms. These forms are then tested out in full scale fishing experiments