Biological and Physical Parameters of the Population Dynamics of Sand Eel Larvae in the Eastern Seto Inland Sea

Abstract

An analytical method for estimating the biological and physical parameters of larvae population from field-observed body length distribution is developed. The hatching intensity function and the survival rate function used in this analysis are given deductively from field data without any assumption on the form of these functions. We applied this method to the population analysis of sand eel larvae in the eastern Seto Inland Sea. The survival rate function is an exponential function with an apparent diminishing coefficient of 0.071 day-1. The hatching intensity function is a normal function whose central date, standard deviation, and maximal value are December 29, 16 days, and 6.86 × 1010individuals/day, respectively. The total number of hatched larve is 2.76 × 1012, which includes the number of larvae hatched in the Bisan Strait (1.79x 1012) and near the Akashi Strait (0.97 × 1012). The 86% of the larvae hatched in the Bisan Strait are transported into the Harima-Osaka area within one-month after hatching. The eastward transportation of the larvae from the Bisan Strait is well explained by the current driven by westerly monsoon wind in winter. © 1990, The Japanese Society of Fisheries Science. All rights reserved.