Scale-Based Study of Linear Growth Rate of Pink Salmon Oncorhynchus gorbuscha (Salmonidae)

Abstract

The retrospective study of the linear growth of pink salmon Oncorhynchus gorbuscha based on measurements of the scales of the fish returned to spawn has been performed at the southeastern coast of Sakhalin Island in 2005–2020. Growth characteristics, such as the increase in its length during sclerite formation, variability and asymmetry of the size composition during growth, are compared with the survival rate of the corresponding generations. Correlation of growth rate with the survival rate of the corresponding generations is observed only during the early marine period of life. The changes in the calculated size composition in surviving fish are similar to some extent to those traced for establishing generations. This phenomenon increases the share of uncertainty in the estimates of size-selective mortality when comparing the body length of underyearlings calculated from the scales with actually observed ones.