The application of a multiple-recapture technique for the study of relatively small fish populations

Expressions are given for the estimation of catchability of untagged fish using the type of multiple-recapture experiments suited to relatively small fish populations. in these experiments all captured fish are released after tagging untagged fish. The realistic assumption that fish populations suffer from different causes of mortality during the sampling surveys is adopted here. The catchability estimate for untagged fish is used to evaluate instantaneous fishing mortality, abundance, survival, instantaneous total mortality and instantaneous natural mortality rates of untagged fish. These estimates are free from Types A and B tagging errors, and take into consideration that catchabilities of tagged and untagged fish are different.