Abstract
To identify factors affecting the somatic growth of the winter-spawning stock of Japanese common squid, the somatic growth of squid caught in the East China Sea, the Pacific Ocean and the Tsushima Strait from 2000 to 2011 was estimated using age determination from statolith microstructure analysis. The relationship between estimated age in days and dorsal mantle length was fitted using a Gompertz growth equation. The residuals of dorsal mantle length from the growth equation differed among year classes, hatch months, and sexes. Although no environmental factors correlated with the annual difference in growth, increased sea water temperature in spring in the Kuroshio-Oyashio transition region corresponded to increased growth with hatch month. Growth was smaller in males than in females during the southward migration, which suggested depressed growth in males due to earlier sexual maturation than in females.
