A Study on the Stock Origin Identification of Chum Salmon Based on Scale Pattern Analysis.

Abstract

A study of fish scale, along with otolithes, backbones and other hard parts,yields ecological information such asthe source river, the rate ofgrowth, aswell asthe fish age. Consequently, the analysis ofscale pattern has been widely used to determine the fish age and their stock origins. In the present paper, an analytical method ofdetermining the stock discrimination ofchum salmon caught from different origins using scale patterns is developed. The analysis has been made by utilizing an auto-correlation coefficient and power spectrum as a function ofthe circuli number.The authors employed a a^scriminant function incorporated with power specialized values of amplitude of circuli pattern data as explanatory variables. Fish from four different rivers were grouped with an averageaccuracy of 88 %.Thescale samples used in the analysis were collected from four rivers (RTokachi in Hokkido, R. Anadyr in Russia, R. Yukon in Alaska andR.Fraser in Canada.) ( keywords: chum salmon, scale pattern, circuli pattern, stock origin, spectrum analysis, aUscriminant function.)