Comparative analysis of growth advantages of selected lines of Crassostrea gigas in different aquaculture areas

Bivalves like the Pacific oyster ( Crassostrea gigas ) are vital protein sources and key aquaculture species in Chinese coasts. In order to find the better oyster lines and their suitable farming sea area, this study evaluated chlorophyll-a (Chl-a), particulate organic matter (POM), and nutrient concentrations (PO₄³⁻-P, NO₂⁻-N, NO₃⁻-N, NH₄⁺-N) across three aquaculture areas (Mazuao, Sanggou Bay, Guazichang) from June 2021 to June 2022, while comparing growth, metabolism, and feeding physiology of diploids, Haida No.1, and triploids C. gigas . Mazuao exhibited the highest Chl-a and POM levels but greater nutrient fluctuations, whereas Sanggou Bay had lower levels of Chl-a and POM. Overall, compared to diploids, Haida No.1 and triploids showed significant growth advantages in different sea areas. Logistic modeling and Genotype and Genotype × Environment biplot (GGE biplot) analysis recommended Haida No.1 for Mazuao due to its lower oxygen consumption, higher filtration rates, and optimal O:N ratios. At the same time, it is recommended to cultivate triploids in Sanggou Bay and Guazichang. This study provides data support for the selection of C. gigas lines for cultivation in different sea areas and offers theoretical guidance for explaining the growth differences among the three C. gigas lines. • The Chl-a and POM contents in three oyster farming areas are Mazuao > Guazichang > Sanggou Bay. • The growth advantages of three oyster varieties (diploids, Haida No.1, and triploids) in three aquaculture areas were compared and analyzed for the first time. • Triploids exhibited significant growth advantages over Haida No.1 and diploids in Sanggou Bay and Guazichang sea areas. • Haida No.1 demonstrated significant growth advantages over triploids and diploids in Mazuao sea area. • Haida No.1 has a lower OCR and AER, as well as a higher FR in Mazuao sea area.