Fluctuation asymmetry of Larimichthys polyactis otoliths from artificial and natural habitats: A study case in Haizhou Bay, China

Abstract

Fluctuating asymmetry (FA) in fish otoliths is a measure of subtle, random differences between paired otoliths, indicating deviations from perfect symmetry due to environmental influences during development. It reflects variations in growth and development within aquatic environments subjected to significant environmental pressures. In our study, we examined 238 Larimichthys polyactis from Haizhou Bay (Jiangsu, China), calculating the Asymmetric Square Coefficient of Variation (CV²_a) for four otolith characters: length, width, perimeter, and area of the left and right lateral sagittal otoliths. Our results showed that otolith width had the lowest CV²_a (1.78), whereas otolith perimeter had the highest (4.52). Notably, the CV²_a for otolith length and width in fish with a body length of less than 110 mm was significantly higher than in fish exceeding 150 mm (P < 0.05). However, we observed no obvious pattern in the CV²_a changes across different habitats for each otolith character, except that a significant difference in CV²_a for otolith width was detected between the NA and the ORA (P < 0.05). We hypothesize that ontogenetic variations in L. polyactis otolith FA are associated with the species' feeding habits and habitat preferences. The spatial sensitivity of otolith FA to environmental pressures remains an area requiring further investigation. Future research will expand our dataset to include otolith FA from additional Sciaenidae species, aiming to enhance the accuracy and reliability of environmental pressure assessments in coastal waters.