A comparative life historical study of the three heterosomes in Sendai Bay.

Abstract

Three heterosomes, stone flounder, plaice and dab are distributed over an almost common area on the continental shelfin Sendai Bay and feed on the common food, infauna organisms. Although the stock levels of the former two species have declined under the recent heavy fishing, conversely that of the latter has increased to a high level. These phenomena seem to result from the fact that while both stone flounder and plaice spawn in late autumn-winter, being long-lived, large-sized and low in intrinsic rate of natural increase rm, and reveal a stable pattern of population change, dab spawns in late winter-sping, being short-lived, small-sized and high in rm, and shows a variable pattern of fluctuation in recruitment.