Fish hook. In use, the hook is covered with bait to attract fish. When a fish eats the bait, it also swallows the hook, which is barbed to prevent it leaving the fish once swallowed. The fish can then be pulled in towards the fisherman. Although a slow and laborious process, hook and line fish- ing does not have the same environmental impact as indiscriminate net fishing, which kills many unwa- nted species of fish, marine mammals and reptiles.