Migration history of an ariid Indian catfish reconstructed by otolith Sr/Ca and δ¹⁸O micro-analysis

Abstract

Understanding catfish ecology is important because catfish constitute one of the largest fish stocks in the coastal Indo-Pacific regions. Recent technological advances have enabled the use of biological electric sensors to understand fish ecology, but their application requires catch and release. Fish otoliths can record ecological changes, and oxygen isotopes and Sr/Ca ratios along the growth direction are independently used to reconstruct the migration history of the fish. Here we report high-resolution measurements of both oxygen isotopes and Sr/Ca ratios of a modern otolith from a marine catfish (Plicofollis tenuispinis) collected from the Gulf of Khambhat, western India. Both sets of data suggest that the catfish migrated from an estuarine environment to the sea during its lifetime. Migration history of the catfish was estimated with monthly resolution aided by numerical modeling. Potential applications of this analysis as an environmental recorder for variables such as temperature and water chemistry are examined.