Shenghao Liu

and 5 more

Tridacna maxima (T. maxima) are widely distributed in shallow areas near coral reefs and hold significant commercial value as a food source and for marine tourism. However, it has been extensively harvested and depleted in many regions, leading to it being listed as endangered species by the International Union for Conservation of Nature (IUCN). While marine protected areas (MPAs) are considered effective conservation tools, it remains uncertain whether existing MPAs adequately protect these vulnerable giant clams. Here, we employed a Species Distribution Models (SDMs) approach, combining occurrence records of T. maxima with environmental variables, to predict their distribution and capture spatiotemporal changes. The findings revealed the importance of land distance and light at bottom in determining the distribution of T. maxima, with suitable habitats predominantly found in shallow coastal waters rather than deep sea areas. Furthermore, we modeled potential distribution areas for T. maxima in 2050 and 2100 under different climate change scenarios, highlighting varying impacts on suitable habitats across different model predictions. To evaluate current conservation gaps, we conducted an analysis by overlaying suitable areas with existing protected areas. The results showed that the potential distribution area of T. maxima is 1,519,764.73 km2, accounting for only 16.10% of the total protected areas. It became evident that the existing protected areas are insufficiently large or well-connected, suggesting their ineffectiveness in safeguarding giant clams. Therefore, management efforts should focus on establishing a network of MPAs along the coastlines of West Pacific-Indonesia, matching the dispersal capability of giant clams. These findings provide valuable insights for the conservation of endangered giant clams, offering a scientific foundation for designing MPA networks in the Indo-Pacific region.

Na Song

and 4 more

Acanthogobius ommaturus is a large, economically important annual fish widely distributed in coastal and estuarine areas. The adults will die after breeding, and its life cycle is only one year. The first chromosome-level genome assembly of A. ommaturus was obtained by PacBio and Hi-C sequencing in this study. The final genome assembly after Hi-C correction was 921.49 Mb, with contig N50 and scaffold N50 values of 15.70 Mb and 40.99 Mb, respectively. The assembled sequences were anchored to 22 chromosomes by using Hi-C data. A total of 18,752 protein-coding genes were predicted, 97.90% of which were successfully annotated. A. ommaturus is phylogenetically closely related to Periophthalmodon magnuspinnatus, Boleophthalmus pectinirostris, diverging approximately 31.9 million years ago with the two goby species. The A. ommaturus genome displayed 597 expanded and 3,094 contracted gene families compared with the common ancestor. A total of 1155 positive selected genes (PSGs) (p < 0.05) were identified. Based on comparative genomic analyses, we obtained several expanded genes such as ACSBG2, LRP1, LRP6 and ZNF638 involved in lipid metabolism. Totally twenty candidate genes were identified under positive selection, which associated with lifespan including ERCC6, IGF1, POLG, and TERT. Interspecific collinearity analysis showed a high genomic synteny between A. ommaturus and Periophthalmodon magnuspinnatus. The effective population size of A. ommaturus decreased drastically during 200-100Ka because of Guxiang ice age, then increased gradually following warm periods. This study provides pivotal genetic resources for in-depth biological and evolutionary studies, and underlies the molecular basis for lipid metabolism.