Effective culture and management of adult tri-spine horseshoe crab, can ensure that stock enhancement programs and aquaculture systems are maintained. To explore suitable feed for animals during the breeding season, Pacific oyster () (oyster group; OG) and frozen sharpbelly fish () (frozen fish group; FG) were selected to feed 20 male and female pairs, respectively. At the end of the experiment, intestinal samples were obtained to measure digestive enzymes activities. The intestinal flora were determined by 16S rDNA sequencing. No eggs were observed in the FG and one adult died. No animals died in the OG, and 9.7 × 10 eggs were obtained. These results show that oysters are more suitable for the development and reproduction of adult than frozen fish. Additionally, the digestive enzyme activity analysis revealed that animals in the OG exhibited higher protein digestibility than those in the FG, but no significant differences in lipid and carbohydrate uptake were observed between the groups. Furthermore, the intestinal flora analysis showed that operational taxonomic units (OTUs) and the Chao1 index were significantly higher in the OG than in the FG, but no significant difference was observed in the Shannon or Simpson indices between the groups. Our data indicate that the oyster diet improved the intestinal microbial diversity of . We hypothesize that nutrients, such as oyster-based taurine, proteins, and highly unsaturated fatty acids, improve protease activity in the digestive tract, alter the intestinal floral structure, and improve the reproductive performance of .

Continued innovation in screening methodologies remains important for the discovery of high-quality multiactive fungi, which have been of great significance to the development of new drugs. Mangrove-derived fungi, which are well recognized as prolific sources of natural products, are worth sustained attention and further study. In this study, 118 fungi, which mainly included spp. (34.62%) and spp. (15.38%), were isolated from the mangrove ecosystem of the Maowei Sea, and 83.1% of the cultured fungi showed at least one bioactivity in four antibacterial and three antioxidant assays. To accurately evaluate the fungal bioactivities, the fungi with multiple bioactivities were successfully evaluated and screened by principal component analysis (PCA), and this analysis provided a dataset for comparing and selecting multibioactive fungi. Among the 118 mangrove-derived fungi tested in this study, spp. showed the best comprehensive activity. Fungi such as and , which exhibited high comprehensive bioactivity as determined by the PCA, have great potential in the exploitation of natural products and the development of new drugs. This study demonstrated the first use of PCA as a time-saving, scientific method with a strong ability to evaluate and screen multiactive fungi, which indicated that this method can affect the discovery and development of new drugs.

Identification, protection and restoration of spawning habitats are vital for protecting the depleted species. Asian horseshoe crabs are ecologically important macroinvertebrates in coastal and estuarine ecosystems. However, their spawning habitat studies were limited to several reports in tropical regions, possibly due to the lack of modified survey methods, particularly in habitats with a lower density of spawning adults, and/or intermingled with anthropogenic structures. In this study, the year-round egg distribution and spawning habitat baselines of and were determined in the northern Beibu Gulf, China. Our findings demonstrated that the peak spawning occurred in June-July and ceased in November-January when the average water temperature dropped below 20 °C. Egg aggregations were found < 10 cm beneath the sediment surface with regular tidal inundation, regardless of seasonal changes, in the vicinity of natural and artificial structures with elevated, mildly sloping substratum within the high tide zones. The nests were characterized by medium-sized sediment grains (0.5-0.9 mm), high temperatures (31-34°C), low water contents (0.8%-0.9%), and total organic carbon contents (0.5%-0.7%), which might maximize the hatching success. The identified nesting beaches were close to nursery habitats for juveniles, and tidal creeks were present as the possible corridor connecting these two important habitats through the dominant mangrove forests. The findings provide valuable insights in the scope of spawning behavior and nest-site selection of Asian horseshoe crabs under a mixture of natural and artificial structures, which could benefit future management efforts for the exploited spawning populations.

Physical factors affecting the survival of eggs were investigated by translocating their eggs between the high intertidal zone and the low intertidal zone of a known spawning site. The mean egg survival rates per day were highest in the mid intertidal zone (45.1%±25.4%) and the lowest in the low intertidal zone (13.3%±27.6%). Differences in the elevation, air exposure time, and water content of the spawning ground were significant factors determining the egg survival rates. Excessive or insufficient air exposure time resulted in inadequate water content at higher and lower intertidal zones and could reduce egg survival. On the other hand, moderate saturation and dehydration were repeated with each tidal movement in the mid intertidal zone. This dynamic is considered as one of the crucial factors for the survival of eggs and is considered optimal for spawning. Therefore, the protection of the mid intertidal zone is imperative for maximizing the egg survival rate in Tsuyazaki Cove where almost all suitable nesting sites have disappeared due to coastal development. By protecting these optimal sites for spawning and recovering other optimal sites on suitable beaches, a positive contribution can be made to future management and conservation. The study also suggests that translocating eggs from marginal to optimal spawning sites might be a recovery strategy for this globally endangered species.

Toll like receptors (TLRs) are the main innate immune 'pattern recognition receptors' of animals, which play a central role in host cell recognition and responses to invasive pathogens, particularly common structures of microbial pathogens. In this study, the gene expression profiles of TLRs in the spleen, head kidney, gill, small intestine, liver, muscle, and heart of healthy were detected by real-time quantitative PCR (qPCR). The TLR family members were widely expressed in different tissues with different basic expression profiles. The highest expressions of TLR1, 5m, 7, 8, 9, 14, and 21 were found in the spleen; the highest expressions of TLR3 and TLR21 were found in the gill; the highest expressions of TLR2 and 5s were found in the small intestine. The second highest expressions of TLR3, 7, and 8 were found in small intestine. The gene expression profiles of TLRs stimulated with DNA, RNA, and lipopolysaccharide (LPS) were also detected in spleen, head kidney and gill. TLR9 and TLR21 were sensitive to DNA; TLR 8 and TLR21 were sensitive to RNA; and TLR1 and TLR14 were sensitive to LPS. The expressions of the other TLR genes showed no significant changes. The results imply that the expressions of these TLR genes in are differently regulated in the whole body and play important roles in the immune response against infection.

The marine biopharmaceutical industry (MBI) has been considered as an important part of the blue economy. The high-quality development of this industry depends on the high-level coordinated development of technological innovation system (TIS). In the present study, the coupling mechanism of industrial innovation input subsystem and innovation output subsystem was analyzed for the first time. On this basis, the development level and coupling coordination level of TIS in China's MBI during 2008-2018 were empirically evaluated with the capacity coupling coordination model. Then, the obstacle factors were diagnosed and recognized with the obstacle model. The results showed that the innovation input index fluctuated at a low level in China's MBI. The innovation output index has basically maintained a growth trend, whereas the quality of development was not high. Although the coupling coordination level of TIS showed a positive change as mild disordered → primary coordinated → well-coordinated, the development type of innovation system has changed from the lagging output of innovation into the lagging input of innovation. Insufficient input of innovation factors remained the main obstacle to the improvement of coordination level. Based on the above analysis, suggestions were put forward from the perspectives of policy and fund guarantees to improve the coupling coordination level in China's MBI.

Surfgrass is a dominant seagrass species along the east coast of Shandong Peninsula, China. Like other seagrasses in the world, surfgrass has been declining in the past decades. To assess the possibility of transplanting in the coastal area, a new surfgrass transplant system was designed and applied to conduct a surfgrass transplantation experiment in a tide pool and a subtidal area, and its survival, morphological and physiological parameters were examined from May 2019 to June 2020. The results showed that after a year since transplantation, more than 65% of the transplants survived and the survival rate was higher in the subtidal site than in the tide pool. The morphological measurements including shoot height, leaf width, number of leaves per shoot, rhizome diameter and elongation rate, and number of roots per shoot were all higher in the subtidal area than in the tide pool, showing that the transplants grew better in the subtidal area than in the tide pool in the study area. These results indicated that surfgrass can be transplanted in the two areas, and it is probably more suitable in subtidal area than in tide pool in the study area.