Microplastics (MPs) pose a growing threat to coral reef ecosystems worldwide. However, data on MP contamination in coral reefs remain limited, hampering accurate ecological risk assessment. This study investigated MP contamination in coral reefs at South Penghu Marine National Park, analyzing 40 samples from 31 coral species. The average MP abundance was 0.32 ± 0.32 MPs/g wet weight, and the mean MP abundance in the coral tissues (0.26 ± 0.26 MPs/g ww) was significantly higher than that in the coral skeleton (0.08 ± 0.10 MPs/g ww). Most MPs were small (<1 mm: >60 %), fibrous (99.7 %), and primarily composed of rayon (59.8 %) and polyester (27.5 %). Significant correlations were found among MP abundance in whole corals, coral tissues, and coral skeletons. The correlation equation established in this study, linking coral skeleton, tissue, and whole corals, can facilitate a more comprehensive understanding of MP pollution level and its associated risks in coral reef environments. Notably, monofilament overgrowth was observed, highlighting the impact of nearby fisheries and recreational activities on MP contamination. These findings provide valuable field-based data on MP pollution levels and the associated risks to corals and offer a novel tool for assessing MP accumulation and potential risks in coral ecosystems.

The coral reefs off the Andaman and Nicobar archipelagos harbour some of the world's diverse reef-associated crustacean fauna, which have not been adequately surveyed. A recent faunal survey in the Andaman Sea on-board the Fishery Oceanographic Research Vessel Sagar Sampada (cruise number 388) revealed a rich diversity of coral reef-associated brachyuran crabs. The article reports four genera, Singhaplax Serène & Soh, 1976, Cavoportunus Nguyen & Ng, 2010, Cyrtocarcinus Ng & Chia, 1994 and Visayax Mendoza & Ng, 2008 occurring in Indian waters for the first time. Seven species namely Singhaplax ockelmanni (Serène, 1971), Urnalana angulata (Rathbun, 1911), Pseudolambrus confragosus (Calman, 1900), Cavoportunus dubius (Laurie, 1906), Cyrtocarcinus truncatus (Rathbun, 1906), Visayax osteodictyon Mendoza & Ng, 2008, and Xanthias joanneae Mendoza, 2013, are likewise reported for the first time from Indian waters.

Ten described species of sea anemones (Anthozoa: Hexacorallia: Actiniaria) serve as hosts to charismatic clownfishes (or anemonefishes) on coral reefs throughout the tropical Indo-West Pacific. Although not diverse in number, the clownfish-hosting sea anemones have large biogeographic ranges, exhibit extensive intraspecific phenotypic appearances, and have been surrounded by a great deal of historical and contemporary taxonomic and nomenclatural confusion. We believe these factors have created challenges for field scientists making real-time species-level identifications of host sea anemones. Subsequently, a surprising amount of peer-reviewed clownfish literature never accounts for the host sea anemone, omitting critical data for understanding the symbiosis ecologically and evolutionarily. Here, we leverage the revolution that has taken place in the realm of digital underwater photography over the past 30 years to provide an updated, practical field guide for the clownfish-hosting sea anemones. First however, we review and revise the nomenclature for each species to better reflect valid changes that were made in the historical literature but never broadly adopted. Next, we demonstrate that machine learning algorithms may be of limited use for automating sea anemone species IDs from digital photographs alone-highlighting the importance of organismal expertise for identifying these animals. Finally, we present high-resolution digital photographs that encompass much of the intraspecific phenotypic variation encountered underwater, discuss important characteristics useful for field IDs, and provide updated range maps for each species to better reflect the known biogeographic range of each host anemone. We hope the increased confidence in field identification provided by this guide will result in more papers incorporating the sea anemone host data into research frameworks and subsequent publications.

In the first comprehensive taxonomic study of the tanaidacean fauna of Singapore, a total of 23 species belonging to two suborders, three superfamilies, 13 families and 22 genera were identified from approximately 2,400 specimens, including 11 species that are possibly new to science. This material was collected from various localities in Singapore waters, from the intertidal zone to subtidal habitats up to 91 m in depth. Many species exhibited a narrow bathymetric distribution and strong affiliation to certain habitats or microhabitats such as mudflats, coral reefs, and barnacle shells on rocky shores. The Singapore Strait yielded 20 tanaidacean species, almost thrice the number of species (7) present in the Johor Straits. Three species were confined to the brackish waters in the inner parts of the Johor Straits and Sungei Pandan. Furthermore, a total of 153 tanaidacean species has now been recorded from Southeast Asia and the South China Sea. The presence of the family Numbakullidae in this region is also documented for the first time.

The Indian Ocean coral reef mantis shrimp, Gonodactylellus demanii (Henderson, 1893), described from the Gulf of Mannar, southeastern India, was thought to range widely, from the northwestern Indian Ocean to the eastern Bay of Bengal, Burma. Reevaluation of G. demanii from throughout its purported range revealed that what was thought to be that species in the northwestern Indian Ocean represents a new species, formally named herein, Gonodactylellus celosinus sp. nov. Gonodactylellus demanii sensu stricto is now known only from the Bay of Bengal (southeastern India to Burma). The taxonomic issues within G. demanii have gone unnoticed until now because the original account was inadequate for recognition of the species and subsequent revisions did not revisit the type or topotypic material. Gonodactylellus demanii is figured alongside G. celosinus sp. nov. to facilitate their recognition.

Marine organisms comprise more than half of the total global diversity. Among them, soft corals constitute a significant group of marine invertebrates widely distributed in the coral reefs. Sacophyton genus, as an essential genus, contains valuable compounds such as macrocyclic diterpenes (cembrene and especially norcembranoid derivatives), sesquiterpenes, and triterpenes (steroids) with various biological activities. Several studies demonstrated which macrocyclic diterpenoids and steroids have anti-inflammatory, anti-neoplastic, anti-tumor, anti-cancer, and antibacterial effects.

Wood-fall micro-ecosystems contribute to biogeochemical processes in the oligotrophic deep ocean. However, the community assembly processes and biogeochemical functions of microbiomes in wood fall remain unclear. This study investigated the diversity, community structure, assembly processes, and functional profiles of bacteria and fungi in a deep-sea wood fall from the South China Sea using physicochemical indices, amplicon sequencing, and metagenomics. The results showed that distinct wood-fall contact surfaces exhibit habitat heterogeneity. The bacterial community of all contact surfaces and the fungal community of seawater contact surface (SWCS) were affected by homogeneous selection. In SWCS and transition region (TR), bacterial communities were influenced by dispersal limitation, whereas fungal communities were affected by homogenizing dispersal. The Venn diagram visualization revealed that the shared fungal community between SWCS and TR was dominated by Aspergillaceae. Additionally, the bacterial community demonstrated a higher genetic potential for sulfur, nitrogen, and methane metabolism than fungi. The sediment contact surface enriched modules were associated with dissimilatory sulfate reduction and methanogenesis, whereas the modules related to nitrate reduction exhibited enrichment characteristics in TR. Moreover, fungi showed a stronger potential for lignocellulase production compared to bacteria, with Microascaceae and Nectriaceae identified as potential contributors to lignocellulose degradation. These results indicate that environmental filtering and organism exchange levels regulated the microbial community assembly of wood fall. The biogeochemical cycling of sulfur, nitrogen, and methane was mainly driven by the bacterial community. Nevertheless, the terrestrial fungi Microascaceae and Nectriaceae might degrade lignocellulose via the combined action of multiple lignocellulases.IMPORTANCEThe presence and activity of microbial communities may play a crucial role in the biogeochemical cycle of deep-sea wood-fall micro-ecosystems. Previous studies on wood falls have focused on the microbiome diversity, community composition, and environmental impact, while few have investigated wood-fall micro-ecosystems by distinguishing among distinct contact surfaces. Our study investigated the microbiome dynamics and functional profiles of bacteria and fungi among distinct wood-fall contact surfaces. We found that the microbiome community assembly was regulated by environmental filtering and organism exchange levels. Bacteria drive the biogeochemical cycling of sulfur, nitrogen, and methane in wood fall through diverse metabolic pathways, whereas fungi are crucial for lignocellulose degradation. Ultimately, this study provides new insights into the driving pattern of community assembly, biogeochemical processes, and lignocellulose degradation in the microbiomes of deep-sea wood-fall micro-ecosystems, enhancing our comprehension of the ecological impacts of organic falls on deep-sea oligotrophic environments.

High lipid diets (HLD) and high plant-protein diets (HPD) exhibit potential fishmeal-saving effects but negatively impact liver health and growth performance in fish. We hypothesized that HLD and HPD impair liver health in pearl gentian groupers (♂ × ♀) through the modulation of intestinal microbiota and bile acid (BA) metabolism. Four diet groups were tested: control diet (CD, 46.21% crude protein, 9.48% crude lipid), HLD (46.37% crude protein, 16.70% crude lipid), HPD (46.50% crude protein, 9.38% crude lipid), and high lipid-high plant-protein diet (HLPD, 46.54% crude protein, 16.67% crude lipid). A total of 300 fish (average body weight = 15.22 ± 0.03 g) were randomly divided into 4 diet treatments (ensuring 3 tanks replicates of each diet treatment, each tank containing 25 fish). After an eight-week feeding period, the HLD and HPD significantly decreased the final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR) and feed intake (FI) in comparison to CD group, with HLPD exacerbating these indicators ( < 0.05). Compared to CD group, the content of total cholesterol (T-CHO) and triglyceride (TG) in liver and serum were significantly increased in HLD group ( < 0.05). Compared to HPD group, the content of T-CHO in liver was significantly decreased, the content of TG in liver and serum were significantly increased in HLPD group ( < 0.05). HLD, HPD, and HLPD impaired liver health by inducing histological damage, inflammation, and oxidative stress. Compared to CD group, the mRNA relative expression of bile salt export pump () and multidrug resistance protein 3 () were significantly increased in HLD group, whereas the mRNA relative expression of sterol-27-hydroxylase (), microsomal epoxide hydrolase (), apical sodium-dependent bile acid transporter (), multidrug resistance-associated protein 3 (), farnesoid X receptor () and G protein-coupled bile acid receptor 5 () were significantly decreased ( < 0.05). Compared to CD group, the mRNA relative expression of , , , organic anion transporters 1 (), , and were significantly decreased in HPD group ( < 0.05). In summary, HLD affects intestinal microbiota, BA metabolism, and lipid metabolism, leading to lipid deposition and liver damage. HPD regulates gut microbiota, BA metabolism, inflammatory responses, and BA receptor expression, impairing grouper liver health. HLPD synergistically combines the adverse effects of HLD and HPD on grouper liver health.

The true state of ocean biodiversity is difficult to assess, and there are few global indicators to track the primary threat of overfishing. We calculated a 50-year Red List Index of extinction risk and ecological function for 1199 sharks and rays and found that since 1970, overfishing has halved their populations and their Red List Index has worsened by 19%. Overfishing the largest species in nearshore and pelagic habitats risks loss of ecomorphotypes and a 5 to 22% erosion of functional diversity. Extinction risk is higher in countries with large human coastal populations but lower in nations with stronger governance, larger economies, and greater beneficial fisheries subsidies. Restricting fishing (including incidental catch) and trade to sustainable levels combined with prohibiting retention of highly threatened species can avert further depletion, widespread loss of population connectivity, and top-down predator control.

Artificial reefs for coral reef restoration are often concrete-based. After concrete is poured, it initially has a high surface pH (approx. 13), which neutralizes within several weeks. During this curing, colonization by marine microalgae is delayed and also macrobenthos such as corals may be impacted. In this study, we evaluated how concrete curing time applied prior to the deployment of artificial reefs affected coral performance. Fragments of five coral species were outplanted onto ordinary Portland concrete discs ( = 10) that had been cured on land. Seven different curing periods were applied, ranging from one day up to four months. The discs with corals were deployed at a Kenyan reef and photographed at the start and end of the experiment. After 1 year, coral cover had increased for four coral species and declined for one, but this was unrelated to concrete curing time. Also, no effect of curing time was seen on the development of other common benthic organisms such as macroalgae or soft corals. We conclude that curing of concrete is unlikely to have any long-term negative impacts on coral performance and therefore, extended curing of artificial reefs prior to coral attachment is unlikely to benefit reef restoration efforts.