Abstract
Investigations were conducted to test the feasibility of using fluctuating asymmetry (FA) in otoliths as an index of the growth rate and condition of the Japanese anchovy, Engraulis japonicus. The differences between the left and right sides of sagittal otoliths in terms of surface area (SA), perimeter (PM), major axis length (MJ) and minor axis length (MN) were measured in juvenile anchovies shortly after metamorphosis. The absolute values of the side differences were used as the FA index for the 4 traits. Size dependence of the FA traits upon standard length (SL) was eliminated by reducing the SL range centering on the mean value. The distribution patterns of the FA traits were statistically equivalent to those of FA. The FA values for SA and PM had a significant negative correlation to the mean growth rates obtained from the otolith daily ring information. In MJ and MN, although the correlation was not significant, FA and the mean growth rate seemed to be in a negative relationship, the latter limiting the upper border of the former. FA analyses using otolith traits have been shown to have the potential to determine condition of the Japanese anchovy.
