Data from: Age-based δ15N and δ13C values of otolith organic matter reveal trophic ecology in marine fishes

Fish inhabiting similar environments face space and resource constraints, develop diverse feeding strategies, and adjust their trophic niches during ontogeny to reduce competition. To investigate this process, we reconstructed the trophic trajectory of five species of the family Sciaenidae by sequentially analysing δ¹³C and δ¹⁵N values in otolith organic matter along the growth axis of the otolith. Isotope values were aligned with age by using growth ring counts and three-dimensional scanning of otolith morphology during organic matter extraction. δ¹³C values indicated habitat shifts and δ¹⁵N values provided insights into trophic level changes. Our findings showed that sciaenids rely on benthic resources throughout their lifespan and may move closer to estuarine environments at approximately 1.5 to 3 years of age. During the larval and early juvenile stages, their diet consists primarily of herbivores and zooplankton. As they grow, competition among age groups and species appears to be minimised.