The crocodile killed its prey by keeping it under and drowning it.

鳄鱼把它的捕获物按在水下。

New methods of setting nets have reduced the bycatch of dolphins but not of other species, such as billfish, turtles and sharks.

设渔网的一些新方法已经减少副捕获物海豚的捕获，但没有减少其它一些生物的捕获，象长嘴鱼、海龟和鲨鱼。