Growth, reproduction, and feeding habits of striped bonito, Sarda orientalis, in the East China Sea

Abstract

We evaluated the growth, reproduction, and feeding habits of striped bonito (Sarda orientalis) in the East China Sea. We collected a total of 289 specimens and determined their age from polished otoliths. The estimated growth function was FLt=586.98{1−exp[−0.76exp(t+0.33)]}, where FLt represents fork length (mm) at age t. Males reached spermiation in April through September, and females spawned in May through July. The main spawning periods for females were May and June. The smallest sexually mature female and male reached 445 and 436 mm in FL, respectively, and were both age 1. The principal prey species were jack mackerel (Trachurus japonicus), scad (genus Decapterus), and anchovy (Engraulis japonicus). The mean carbon and nitrogen stable isotope ratios of the striped bonito were −16.6‰ and 13.7‰, respectively. The relative contribution of prey species based on stable isotope ratios indicates that the striped bonito is an opportunistic feeder of small pelagic fishes. These biological and ecological data on the striped bonito will be of great importance for stock assessment and the development of ecosystem-based fisheries management schemes.