The dynamics of growth and maturation age in the scallop Adamussium colbecki in Tera Nova Bay, Antarctica

Abstract

The endemic Antarctic scallop Adamussium colbecki, one of the most common bivalve species, plays an important ecological role in Antarctic ecosystems. In this study, we investigated the size frequency structure, shell height, and gonadosomatic index (GSI) of A. colbecki in coastal areas near Jang Bogo Antarctic Research Station in Terra Nova Bay. A generalized von Bertalanffy growth function was fitted to shell height-at-age measurements of 389 individuals (H∞ = 115.4 mm and K = 0.064 year-1). Large-sized individuals (70–84 mm) of A. colbecki were ∼2X as prevalent, accounting for more than 50% of the overall density. Individuals younger than 6 years showed a lower growth rate compared to that reported in previous studies. GSI indicated that sexual maturity of both females and males was observed in individuals over 50 mm shell height at the age of approximately 9 years. The maturity was delayed by two to four years when compared with previous data in Terra Nova Bay due to the low growth rates of the young population. Therefore, the low growth rate of young individuals and the delayed maturity age may have deleterious effects on population growth. The information reported here provides baseline scientific data that can be used to develop better informed management decisions and aid in defining an effective management strategy for Antarctic scallops.