From January to December 2022, a study on biofouling was conducted in the southeast wharf of Leizhou Bay. Over a year, a total of 44 species were recorded, belonging to 10 phyla. The dominant species in the community were coastal warm-water organisms typical of subtropical inner bay environments. The peak settlement period occurred between April and September, with the highest adhesion strength observed in summer. Among the dominant and representative species, Perna viridis stood out, followed by Podocerus brasiliensis, Crassostrea ariakensis, Musculus senhousei, Dreissena polymorphia, Caprella equilibra, Gammaropsis digitata, Stenothoe gallensis, Parhyale hawaiensis, Amphibalanus reticulatus, EnteromorpHa prolifera, Gracilaria bailinae, and Pennaria disticha. Due to competition for settlement space and food, individuals in the biofouling community exhibited mutual dependence or restraint and displayed a specific spatiotemporal distribution pattern adapted to environmental factors. Temperature was the most crucial environmental factor determining the geographic distribution of biofouling species, reflecting the differences in community composition across various climate zones. The number of species, settlement stage, and settlement rate of biofouling organisms were closely tied to water temperature. Additionally, local natural conditions such as salinity, dissolved oxygen, and light, as well as human activities such as aquaculture production, played significant roles in the settlement of biofouling organisms.

Sex is an important biological variable in animal physiology and environmental-stress research, but its influence on fish intestinal transcriptomic profiles remains insufficiently characterized. In this study, adult female and male Mugilogobius chulae were used to characterize baseline intestinal sex differences and to evaluate their relevance to short-term sulfamethoxazole exposure. Fish were assigned to solvent control or nominal 1 mg/L sulfamethoxazole exposure for 7 days, and intestinal tissues were analyzed by histology, RNA sequencing (RNA-Seq), functional enrichment analysis, gene set enrichment analysis, and quantitative real-time polymerase chain reaction validation. Representative histological sections showed qualitative sex-related differences in intestinal morphology. Transcriptomic analyses revealed that intestinal variation was more strongly associated with sex than with pooled treatment status. The pooled female-versus-male comparison identified 85 differentially expressed genes, whereas the pooled treatment-versus-control comparison yielded no significant differentially expressed genes under the current threshold. Functional enrichment and gene set enrichment analyses showed that female-biased intestinal profiles were mainly associated with nutrient absorption, lipid and sterol handling, membrane transport and epithelial interface-related pathways, whereas male-biased profiles were more closely related to RNA processing, oxidative metabolism, translation, protein targeting and mucosal immune signaling. These findings demonstrate sex-dependent intestinal transcriptomic signatures in M. chulae and support sex-aware intestinal transcriptomic analysis in aquatic animal omics and environmental-stress evaluation.

As a typical turbid-water reef coral, Turbinaria peltata shows strong tolerance to high temperature and sediment disturbance, yet its basin-scale niche drivers and glacial distribution dynamics across the Indo-West Pacific remain unclear. Here we constructed optimized MaxEnt models using 322 independent distribution points and 21 non-collinear marine environmental variables for modern and Last Glacial Maximum (LGM) scenarios. The model average test AUC reached 0.9874, showing excellent predictive performance. Water depth acted as the most influential predictor in the model (contribution = 44.76%), followed by distance to land and warm-season sea temperature; habitat suitability had an extremely weak linear correlation with depth (R² = 0.05), consistent with a strongly nonlinear response along the depth gradient. Modern suitable habitats are mainly concentrated in Southeast Asia and northern Australia, with the South China Sea at the species’ northern margin. Massive shelf exposure during the LGM severely shrank its range, and three potential glacial refugia (northeastern Australia, Madagascar coast, Red Sea–Gulf of Aden) were identified. These refugia may have maintained coral populations through glaciation and contributed to the present-day biogeographic patterns of this species. Our findings provide quantitative spatial evidence for targeted conservation of nearshore stress-resistant corals under climate warming.

Reliable normalization is essential for accurate quantitative real-time PCR (qRT-PCR) analysis, yet suitable reference genes have not been systematically evaluated in Mugilogobius chulae, an emerging marine experimental fish used in physiological and environmental research. In this study, 17 candidate reference genes were evaluated in five tissues (brain, gill, gonad, intestine, and liver) of sexually mature male and female M. chulae under solvent control (DMSO), bisphenol A (BPA), cadmium (Cd), and sulfamethazine (SMX) treatment conditions. Gene-expression stability was assessed using the comparative ΔCt method, NormFinder, geNorm, BestKeeper, and the integrated RefFinder ranking. The results showed that reference-gene stability was strongly tissue-specific and analysis-dependent. The integrated RefFinder analysis identified eif3h, rpl7, rps4x, stau1, and ef1y as the most stable genes in the pooled dataset, whereas ube2, hprt1l, and aldob were the least stable. geNorm analysis indicated that two reference genes were sufficient for brain, gill, intestine, and liver, whereas four were required for the gonad and six for cross-tissue comparisons. These findings provide the first systematic basis for reference-gene selection in M. chulae and establish an important methodological foundation for future qRT-PCR studies in this species, particularly in research on endocrine disruption, reproductive physiology, and marine ecotoxicology.

Marine heatwaves (MHWs) are escalating threats to coral reef ecosystems, yet the host transcriptomic mechanisms underlying acclimatization to repeated thermal stress remain poorly understood. Using de novo RNA sequencing, we tracked the temporal transcriptomic responses of the scleractinian coral Turbinaria peltata across two consecutive MHW-recovery cycles. The second heatwave elicited fewer differentially expressed genes (DEGs) than the first (279 vs. 379), whereas the second recovery phase showed the largest DEG set (399). Functionally, the first heatwave triggered acute stress defense and signal suppression, while the first recovery engaged extracellular matrix remodeling and calcium-mediated tissue repair, indicating incomplete restoration. The largest DEG set during the second recovery indicates that recurrent thermal stress imposes cumulative physiological costs demanding more extensive molecular reorganization—spanning metabolic reprogramming, mTOR and Wnt signaling, and sustained oxidative-stress management. Together with prior physiological and microbiome evidence in this species, our results support a model in which repeated heat exposure progressively shifts the coral host from acute shock defense responses toward compensatory metabolism and structural repair. Recovery thus emerges as an active but increasingly costly molecular adjustment under recurrent MHW regimes. These findings identify candidate molecular markers for evaluating coral resilience under intensifying MHW regimes.