Relationship between Otoliths and Fish Length of Selected Catfish in Niger Delta, Nigeria

Abstract

Catfish are important fishery resources in the Niger Delta therefore they require studies on its growth patterns and morphometrics. This study examined the relationship between the length and width of catfish otoliths and their fish length. Catfish samples were harvested from New Calabar and Ase Rivers, Niger Delta, Nigeria, by fishers using cast net and purse seines. The fishes were identified, measured, otoliths removed and measured using standard methods. Simple linear regressions expressed the relationship between otolith dimensions and fish length. A total of 80 individuals made up of 7 species from 5 families (Ariidae, Claroteidae, Claridae, Schilbeidae and Mochokidae) were selected for this study. Correlation analysis between the morphometric parameters of the otoliths from the catfish species in the study area revealed a strong positive correlation between the total length of the fish and the length of the otoliths, with R2 values ranging from 0.86 to 0.98. There was also a strong positive correlation between total fish length and otolith width. The relationship between otolith length and width with the fish length in this study showed curvilinearity, indicating the usefulness of the otolith proportions in back calculation of the length of the fish in biological and paleontological studies.