Growth, Population Age Structure and Mortality of the Limpet Collisella heroldi (DUNKER, 1861)(Gastropoda: Acmaeidae) in an Intertidal Rocky Shore, in Southern Hokkaido.

Abstract

The growth rate, population age structure, and mortality of the limpet Collisella heroldi in the intertidal area of Usujiri, Hokkaido were studied. Annual ring method and size distribution were used in determining the growth rate. C. heroldi showed a typical seasonal growth pattern: from April to October all individuals grew fast, coinciding with the development of the gonads, while in other months adult limpets showed little growth. A von Bertalanffy growth equation modified by Pauly and Gaschutz gave a good fit to the growth pattern. C. heroldi population showed a stable age structure, More than 50% of the population were 0-year juveniles. A stable mortality rate of about 65.5% per year was observed.