The quantity of fish that can be taken by a fishing unit, for example an individual, community, vessel or fleet, assuming that there is no limitation on the yield from the stock. (FAO, 1997).; Usually expressed in terms of some measure of vessel size, such as gross tonnage, hold capacity, horsepower. Reflects potential fishing effort rather than nominal fishing effort.; The maximum amount of fish that could be taken in a fishery or by a single fishing unit (e.g. a fisher, community, vessel or fleet) over a period of time (e.g. season, year), given the biomass and age structure of the fish stock and the present state of the technology, in the absence of any regulated catch limitations and if the means available are fully used.