What does CPUE measure?

In fisheries and conservation biology, the catch per unit effort (CPUE) is an indirect measure of the abundance of a target species. Changes in the catch per unit effort are inferred to signify changes to the target species’ true abundance.

Is catch per unit effort proportional to abundance?

By far the most common index to abundance in fisheries work is catch per unit effort (CPUE). The assumption is that the number of fish caught per unit of effort expended (often time) is proportional to stock size.

How do you measure the catch per unit effort of a certain fishing gear?

 Catch per unit of effort is often used as a measurement of relative abundance for a particular fish; the total catch divided by the total amount of effort used to harvest the catch.

What is the general purpose of CPUE analysis?

The main objective of the analysis is to estimate a year effect. The year effect is used to represent the annual relative levels of abundance and is used as the relative index of abundance to include in the stock assessment.

Why is catch per unit effort used?

Catch-per-unit-effort (CPUE) is often used to monitor wildlife populations and to develop statistical population models. Animals caught and released are often not included in CPUE metrics and their inclusion may create more accurate indices of abundance.

What does fishing effort mean?

The fishing effort is a measure of the amount of fishing. Frequently some surrogate is used relating to a given combination of inputs into the fishing activity, such as the number of hours or days spent fishing, numbers of hooks used (in long- line fishing), kilometres of nets used, etc.

How do you read a catch per unit effort?

Raw cpue, also called nominal cpue, is simply the total catch divided by the sum of an observable measure of effort associated with the catch, e.g. total number of hooks for longline fisheries. Cpue is usually calculated for a defined time period (e.g. year), but can also be restricted by spatial or other strata.

Is a high CPUE good?

Increases in CPUE may mean that a fish stock is recovering and more fishing effort can be applied. CPUE can therefore be used as an index of stock abundance, where some relationship is assumed between that index and the stock size.

How is CPUE calculated?

CPUE is calculated by dividing the catch of each fishing trip by the number of hours fished during that trip. This gives CPUE in units of kilograms per hour.

What does CPUE stand for?

Catch-Per-Unit-Effort
Catch-Per-Unit-Effort (CPUE) – also called catch rate – is frequently the single most useful index for long-term monitoring of a fishery. Declines in CPUE may mean that the fish population cannot support the level of harvesting.

What can be the effect of harvesting the maximum sustainable yield MSY every year?

If a constant number of individuals is harvested from a population at a level greater than the MSY, the population will decline to extinction. Harvesting below the MSY level leads to a stable equilibrium population if the starting population is above the unstable equilibrium population size.

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