The catch of fish, in numbers or in weight, taken by a defined unit of fishing effort. Also called; catch per effort, fishing success, availability. Ex: tons of shrimp per tow, pounds of fish per hundred longline hooks.

Usually applied to the harvesting of a natural resource (e.g. marine fish), the total catch (in terms of numbers or biomass) divided by the total harvesting effort (e.g. a product of the total number and size of ships and the number of days that they fished).

A sampling method used to compare the relative abundance of fish between one area of habitat and another where the only common link is the method used to catch the fish. Catch per unit effort is typically expressed as the number of fish captured divided by the amount of time it took to catch the fish (e.g., fish per hour) or the number of fish captured per net set.