All organisms are subject to various sources of mortality.
These include death by starvation, death by disease or physical injury, and death by predation. In fisheries biology, we are interested in both natural and human sources of mortality. In order to manage fisheries, we need to understand how much natural mortality goes on, so that we do not set fishing rates so high that populations have no chance to replenish themselves. In these lecture notes, we focus on an important source of natural mortality in fish, namely, predation. Predation can be thought of as one of the major ecological relationships among living organisms.