Study on recapture effect and migration-dispersal characteristics of tagged Acanthopagrus schlegelii and Epinephelus coioides in Aotou Bay

External anchor tagging is one of the most widely used fish marking methods at present. To evaluate the effect of stock enhancement and release of tagged Acanthopagrus schlegelii and Epinephelus coioides in Aotou Bay waters, we tagged and released a total of 10 500 individuals of A. schlegelii with an average body length of (11.07±0.96) cm and an average body mass of (48.1±10.0) g, as well as 5 200 individuals of E. coioides with an average body length of (15.42±1.29) cm and an average body mass of (96.4±20.1) g by the anchor tagging method in November 2025. Up to February 2026, 475 tagged A. schlegelii were recaptured with a recapture rate of 4.52%; at 81 d after release, their body length and body mass increased by 55.86% and 97.92%, compared with the initial values at release. A total of 212 tagged E. coioides were recaptured with a recapture rate of 4.08%; at 74 days after release, their body length and body mass increased by 25.97% and 37.97%, respectively. Sea fishing was the main recapture method for both species. The recapture rate of tagged A. schlegelii fluctuated drastically within 1–26 d after release, peaking at 0.84% on the 8^th day post-release and then declining rapidly. In contrast, the recapture rate of tagged E. coioides showed an overall increasing trend within 1–26 d after release, reaching a peak of 1.15% on the 26^th day post-release followed by a rapid decrease. The released tagged fish migrated and diffused in a near-shore radial pattern, with their moving paths concentrated near the islands and reefs and towards the inner bay. The diffusion range of A. schlegelii was larger than that of E. coioides, with the farthest distribution reaching the waters of Mabianzhou Island. The Pearson correlation coefficients between body length and body mass of A. schlegelii and E. coioides were 0.961 and 0.909, respectively (p<0.01), and the exponent b of the length–mass power function was less than 3 for both species, indicating that both fish were in a state of negative allometric growth.This study is expected to provide a scientific basis for fish tagging-release practice and fishery resource conservation in this sea area in the future.