Fish stock - that portion of the population that is considered in terms of existing and potential exploitation.

The portion of a renewable fishery resource that can be periodically extracted from a population from a unit area (volume) for food, industrial purposes without significant detriment to its overall welfare.

The amount of production that can be withdrawn at intervals over a long period of time without affecting the ability of the resource to reproduce offspring.

These are subpopulations of a particular fish species for which internal parameters (growth, recruitment, mortality and fishing mortality) have traditionally been regarded as significant determinants of stock population dynamics, while external factors (immigration and emigration) have traditionally been ignored.