Relationship between Sagittal Otolith Size and Fish Size in Engraulis encrasicolus and Sardina pilchardus (Osteichthyes: Clupeiformes) in the Southern Aegean Sea, Turkey

Abstract

The objective of this study was to determine the regressions between otolith size (length and height), otolith weight vs. fish length, and weight of European anchovy Engraulis encrasicolus (Linnaeus, 1758) (n=360) and European pilchard Sardina pilchardus (Walbaum, 1792) (n=360), living off Gulluk Bay, Turkey. Fish were caught using a purse seine between January and March 2014 in the southern Aegean Sea. No differences were found between the size and weight of the left and right otoliths. Equations were used to reconstruct the original dimensions of prey from the size of hard structures found in food samples of piscivorous predators living in or in the vicinity of the aquatic habitat. A linear regression model was used to determine the relationship between fish length and otolith size, whereas an exponential regression model was used to describe the relationships between lengths and weights of otoliths and fish for both species. All regressions yielded high coefficients of determination (r(2)) of 0.78-0.93 for E. encrasicolus and 0.80-0.95 for S. pilchardus. We conclude that otolith length and otolith weight are good indicators of the length and weight of the two species.