Overfishing is the act whereby fish stocks are depleted to unacceptable levels, regardless of water body size. Resource depletion, low biological growth rates, and critically low biomass levels (e.g. by critical depensation growth properties) result from overfishing. For example, overfishing of sharks has led to the upset of entire marine ecosystems.
The removal of a sufficiently large number of certain fish from a body of water such that breeding stocks are reduced to levels that will not support the continued presence of the fish in desirable quantities for sport or commercial harvest.