Fisheries Technology Institute, Hyogo Prefectural Technology Center for Agriculture, Forestry and Fisheries, Akashi, Hyogo 674-0093, Japan
Age and growth were estimated for marbled sole, Pleuronectes yokohamae, in Harima Nada and Osaka Bay, the Seto Inland Sea, Japan, in the study periods of 1986-1989 and 1998-2001, based on otolith ring analyses. Translucent otolith rings were formed once a year from May to January or February. Ages were determined from the number of annual growth rings on the otoliths, and growth was estimated by von Bertalanffy's growth equations using Walford's and the least squares methods. The body lengths estimated by Walford's method in each age were smaller than those estimated by the least squares method and it was concluded that the growth estimated from Walford's method was underestimated.
The growth model estimated by the least squares method showed that females grew faster than males in 1986-1989 and 1998-2001. The growth parameters of both sexes significantly differed between those periods, suggesting that marbled sole in 1998-2001 grew faster than in 1986-1989. Also, the growth parameters of both sexes significantly differed between Harima Nanda and Osaka Bay sampled in 1986-1989 and the northern Kii Channel in 1986-1988.