Appropriateness Evaluation of Releasing Area for Four Marine Organisms in Stock Enhancement: A Fatty Acid Approach

Abstract

In light of the ongoing depletion of global fishery resources, there has been a growing trend towards increasing the scope of stock enhancement activities. The objective of these efforts is to replenish the diminishing fishery resources and restore the ecological balance within marine biological communities. Nevertheless, the efficacy of the stock enhancement project has been hindered by the differential growth and environmental adaptability of released species, which can be attributed to the influence of abundant food resources. As a consequence, the project has not yielded the anticipated outcomes. One useful strategy for enhancing the efficacy of stock enhancement is the deliberate allocation of appropriate habitats for diverse released organisms. Fatty acids were extracted by the Folch method and the composition and content of muscle fatty acids were determined by gas chromatography mass spectrometry. This study examines the fatty acid composition of four commercially important species, namely, little yellow croaker (Larimichthys polyactis), red sea bream (Pagrus major), swimming crab (Portunus trituberculatus), and ridgetail white prawn (Exopalaemon carinicauda). The sum of available docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) is employed as an indicator to assess the appropriateness of the marine environment for releasing these species (DE). The red sea bream exhibited the lowest DE value of 13.69% in the northern coastal water of the Bohai Sea, and the little yellow croaker displayed the lowest DE value of 10.91% in the southern coastal water of the Shandong Peninsula. Conversely, the DE values of other seas were comparable, averaging 20.16%. The range of the DE value of the swimming crab across various coastal waters was observed to be between 33.59% and 45.21%. The ridgetail white prawn had a DE value of 21.10% in the coastal water of Yancheng City, Jiangsu Province, as well as the southern coastal water of the Shandong Peninsula, and a DE value of 31.75% in the southern and central coastal waters of Zhejiang Province. The findings of the study indicate that the Bohai Sea and the northern region of the Yellow Sea are the appropriate stock enhancement areas for red sea bream. Similarly, the Yellow Sea and the northern part of the East China Sea are identified as suitable habitats for the little yellow croaker. The swimming crab, on the other hand, is adapted to be released in the Yellow Sea, the Bohai Sea, and the East China Sea. The north of the central part of the East China Sea is an appropriate release area for the ridgetail white prawn.