Surplus killing seems to occur when prey are vulnerable and easy to catch - in winter, for instance, when there is deep snow.

“有剩余的捕杀”只是发生在那些在冬季很容易捕食的小动物身上。

youdao

Fishermen need to have a secure income that is not tied to what they can catch, but rather how sustainably they manage fish stocks and how efficiently they harvest an agreed surplus.

BBC: Casting a net far into the future