Men, Birds and Anchovies in the Peru Current—Dynamic Interactions

TLDR: In this paper, the catch-per-effort of the commercial fishery of the anchoveta, Engraulis ringens, in the Peru Current during 1966, 1967 and 1968 has been above that expected from earlier analysis of the relation of apparent abundance to commercial fishing effort.

Abstract: Apparent abundance, measured by catch-per-effort in the commercial fishery, of the anchoveta, Engraulis ringens, in the Peru Current, during 1966, 1967 and 1968 has been above that expected from earlier analysis of the relation of apparent abundance to commercial fishing effort. During these years there has also been apparent enhanced recruitment, measured by the catch-per-effort of the entering year-class. During these same years, however, the guano birds, that also feed on E. ringens, have been at a low population level compared to previous years. Combining the fishermen's catch with the harvest by guano birds, for fishing years 1960–61 through 1967–68, relating this to the total fishing effort by the two predators, and treating this as a single fishery, it is shown that the combined data are well fitted by the logistic model for the catch-effort relationship. The maximum sustainable yield of the combined fishery is about 10 million metric tons per year, presently shared, approximately, 9.3 mil...