Age composition and growth difference of chum salmon migrating to Ussuri River

Abstract:

Age determining and biological parameters measuring were conducted for the chum salmons collected form the stocks migrating to Ussuri River for breeding. Back calculated fork length was computed and the difference of growth between different maturation age groups was studied based on it. The result showed that the age groups of chum salmon were composed by 2+，3+，4+ age group, and female and male individuals have different age composition, average age are 3.43 and 3.24 respectively. Von Bertalanffy growth function was used to fit the fork length growth of chum salmon. ARSS（Analysis of the residual sum of squares）was used to judge the difference of chum salmon among the three age groups. The result showed the growth of chum salmons at different maturation age group has significant difference (P<0.05).The stocks at low maturation age group grow faster than the high age groups. With the age increasing growth speed become slower, but the growth index is not the smallest one at the last year in the ocean life stage. Genetic factor, Ocean environment conditions, intra and interspecific interaction affect the growth of chum salmon all together.