Relationships between shrimp community structure and environmental factors in Hainan Island during spring and winter

This study aims to investigate the spatiotemporal differentiation patterns of shrimp communities in the waters surrounding Hainan Island. Bottom trawl surveys were conducted at 50 stations in December 2023 (winter) and April 2024 (spring). Community characteristics were analyzed using the Shannon-Wiener diversity index (H′), Pielou evenness index (J′), Margalef richness index (D), and index of relative importance (IRI). Similarity Percentage Analysis (SIMPER) was employed to identify key contributing species, and Canonical Correspondence Analysis (CCA) was performed to explore the relationships between community structure and bottom environmental factors. A total of 68 shrimp species were collected, belonging to 38 genera and 17 families, with Penaeidae being the absolutely dominant family. The community structure exhibited clear seasonal succession and water depth gradient differentiation. In winter, the dominant species were Metapenaeopsis barbata and Mierspenaeopsis hardwickii, with relatively high diversity (H′ = 1.89) and evenness (J′ = 0.67); diversity in deep-water areas was significantly higher than that in shallow-water areas. In spring, the dominant species shifted to Trachysalambria dentata and M. barbata, with a marked decrease in diversity (H′ = 1.15, J′ = 0.61). SIMPER analysis revealed that T. dentata had the highest biomass contribution in spring (β = 0.78), serving as a key factor driving the trend of resource distribution shifting from shallow to deep waters and leading the community toward high-density, low-diversity conditions. CCA analysis indicated that water depth (Depth), temperature (T), and dissolved oxygen (DO) were important environmental factors common to both seasons, with chlorophyll-a (Chl.a) also becoming a significant factor in spring. This study demonstrates that water depth gradient influences the spatial pattern of shrimp communities, while seasonal outbreaks of key species-particularly T. dentata-together with variations in environmental factors, predominantly govern the temporal dynamics of community structure. This research reveals the spatiotemporal distribution characteristics and key driving factors of shrimp resources in Hainan Island waters, providing a theoretical basis and practical reference for scientific resource assessment, ecosystem-based fisheries management, and biodiversity conservation in this area.