Most fish species of by-catch were commercially undersized species, with damage to juvenile fish resources.

副渔获中大部分鱼种未达到可捕规格，对幼鱼资源造成损害。

youdao

Because of the selectivity of fishing gear and mixed distribution of fish species, there will be inevitably by-catches and discards when people catch the target species.

由于渔具不同的选择性和多鱼种鱼类共栖，人们在对目标种类进行捕捞时，不可避免地产生副渔获物及其抛弃。

youdao

The Scottish fleet has been working to minimise discards by using nets which only catch certain species of fish.

BBC: EU fishing discards deal welcomed by Scots minister