不同底质对拟穴青蟹仔蟹生长、行为及水体微生物的影响OA

To investigate the effects of different substrate environments on the growth performance,behavioral strategies,and water microbial communities of juvenile mud crabs(Scylla paramamosain),a cultivation experiment was conducted under three substrate conditions,namely,marine mud,marine sand,and vegetation.Growth indicators,behavioral patterns,and the structure of the water microbial community were monitored.The results showed that the survival rate and molting frequency of juveniles in the vegetation group were significantly higher than those in the marine mud and marine sand groups(P<0.05).Meanwhile,the final carapace width was significantly greater in the marine mud and vegetation groups compared to the sand group(P<0.05).The sand group exhibited the lowest weight gain rate and specific growth rate.Behaviorally,the juveniles had a significant preference for inhabiting marine mud substrates(P<0.05).The vegetation group showed the highest behavioral diversity,encompassing clinging,epibenthic,and burying behaviors.Meanwhile,only epibenthic and burying behaviors were observed in the other two groups.The structure of the water microbial community was significantly influenced by substrate type.Microbial richness was highest in the marine mud group(P<0.05),though no significant differences in diversity were detected among the three water types(P>0.05).At the phylum level,Proteobacteria dominated in marine mud water,Bacteroidota was predominant in marine sand water,and Desulfobacterota showed higher abundance in vegetation water.At the genus level,Marivita was identified as the dominant genus common to all groups,with the highest relative abundance observed in the vegetation water.The study indicates that vegetated substrates reduce predation pressure by providing physical shelter,while marine mud substrates are the preferred habitat for juveniles.Both substrate types help shape microbial communities conducive to water quality maintenance,promoting survival,molting,and behavioral diversification in juvenile crabs.In contrast,marine sand substrates are unfavorable for juvenile growth.This research elucidates the dual mechanisms—physical structure and microbial community—through which substrate type influences the ecological performance of juvenile mud crabs,offering a theoretical basis for optimizing temporary rearing strategies and natural habitat management for S.paramamosain.