Abstract:The issue of population division of the small yellow croaker (Larimichthys polyactis) has been controversial since the 1950s. Previously used methods for studying the population classification of these marine fish populations include the mark-recapture method, catch yield statistics method, parasite labeling method, morphometric/meristic characters method, molecular biology method, and chemical fingerprints of the calcified structures method. Each of these techniques has its own reliability as well as limitations. In this study, the content of delta 13C (δ13C) and delta 18O (δ18O) in the left sagittal otolith samples of 92 Larimichthys polyactis obtained from the investigation of fishery resources in Bohai Sea and Yellow Sea, was determined using stable isotope mass spectrometry. A cluster analysis was carried out based on differences in the content of delta 13C and delta 18O among samples. The results showed that the early supplement population of Larimichthys polyactis, predominant during the autumn season, in the Yellow Sea and Bohai Sea can be divided into four major groups, which are listed as Bohai and the northern Yellow Sea population, the central Yellow Sea population, the offshore population of southern Yellow Sea, and the coastal population of southern Yellow Sea. However, there was no station between the offshore population of the southern Yellow Sea and the three other populations in the Yellow and Bohai Sea. The discriminant and cluster analysis revealed that the successful rate of discrimination was 75.9%, 80.0%, 81.0%, and 95.6% in the Bohai and northern Yellow Sea population, the central Yellow Sea population, the offshore population of southern Yellow Sea, and the coastal population of southern Yellow Sea, respectively. The overall successful rate of discrimination was recorded to be 82.6%. The population of southern Yellow Sea was subdivided into offshore and coastal populations for the first time, and no station crossing between the two populations was recorded. With this study, we propose to establish the basis for population classification of Larimichthys polyactis.
