According to the feeding type, we can divide fish species into benthic feeders and pelagic feeders.The activity in pelagic feeders increases with the increase of trophic level.

• 若将鱼种依食性分为底栖掠食及上层掠食之鱼种，则上层掠食之鱼种其体内之活性随营养阶层增加而增加。