熊本県緑川河口域に分布するムツゴロウの年齢と成長

概要

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The age and growth of the herbivorous mudskipper Boleophthalmus pectinirostris were studied in the mud flat of the Midori River, Kumamoto Prefecture. A mark is formed on the second pectoral radials twice a year, in summer (age-indicating) and late autumn. The specimens (829 individuals collected from 1986 to 1989) mostly consisted of one and two year olds with the oldest being four years old. The fish grows fast from spring to late autumn. However the annual growth rate falls markedly after two years of age. Growth was found to vary both within and between year classes, probably due to the feeding behavior resulting from being confined to a bounded grazing area. The fish having less growth in the first year grew more in the second year. However, the year classes attaining a larger size by the first winter would still keep their superiority in size in the following years.
日本水産學會の論文