Some Aspects of Population Dynamics of the Asteroid Luidia quinaria in Ise Bay, Central Japan

Abstract

Abstract: Some aspects of the population dynamics of the asteroid, Luidia quinaria, in Ise Bay, central Japan, were examined in relation to environmental factors based on data collected from 1993 to 1999. Abundance of the asteroid was significantly different between seasons and between years. The main recruitment episode occurred in autumn every year, although small-scale recruitment was observed in spring. Interannual variation in the abundance of new recruits was marked, being most intense in 1996 and 1997. Severity and period of occurrence of oxygen-poor water(with a dissolved oxygen content at the bottom of less than 3ppm), which develops every summer, play an important role in determining the population structure and growth of asteroids of the 0⁺ and 1⁺ age classes. The von Bertalanffy growth equation provided the best fit to our data.