This study examined the survival rates of Anadara broughtonii and Chlamys farreri with varying heights throughout winter and summer aquaculture periods under varying ratios of mixed-culture conditions in marine environments. The aim was to assess the viability and economic advantages of mixed-culture practices among different bivalve species. Results indicate that the winter (from December to February of the following year) mortality rate for A. broughtonii in mixed culture ranges from 12.04% to 16.85%, markedly lower than in single-species cultures. Mixed-culture A. broughtonii measuring 2.5–4.0 cm exhibit a significantly reduced summer (from July to September) mortality rate compared to those in single-species cultures (p < 0.05). No significant mortality difference was observed between the monoculture and polyculture of C. farreri. Growth rates of C. farreri and A. broughtonii showed no significant differences between monoculture and polyculture conditions. The optimal size for combining two different species of bivalves is 2.5 cm, with a 1:1 ratio being the most effective. An equal number of seedlings were cultivated across various seawater aquaculture systems for a period of one year. The survival rates of monoculture seedlings of Anadara broughtonii and Chlamys farreri were 60.34% and 86.55%, respectively. In contrast, polyculture seedlings exhibited higher survival rates after one year of mariculture, with Anadara broughtonii at 73.36% and Chlamys farreri at 89.74%. The polyculture of A. broughtonii and C. farreri in suspension cages demonstrates a favorable input–output ratio of 1:2.02. This approach effectively reduces winter and summer mortality rates of A. broughtonii, representing an efficient new method for marine bivalve aquaculture.

The study examines the survival status of Scapharca broughtonii and Scallop Chlamys farreri under diverse seasons, sizes, and mixed breeding ratios. The objective is to explore the feasibility and economic benefits of the mixed breeding patterns of different shellfish varieties. The findings demonstrate that the overwintering mortality rate of mixed-cultured S.broughtonii ranges from 12.04% to 16.85%, which is conspicuously lower than that of individually cultured S.broughtonii. The summer mortality rate of mixed-cultured S.broughtonii with a size of 2.5 - 4.0 cm is significantly lower than that of individually cultured S.broughtonii (P < 0.05). There is no notable difference in the mortality between monoculture and polyculture of C.farreri. There is no significant disparity in the growth of C.farreri and S.broughtonii in monoculture and polyculture. The optimal polyculture size of the two scallops is 2.5 cm, and the ideal polyculture ratio is 1:1. The co-culture model of S.broughtonii and C.farreri in suspension cages has a high input-output ratio (1:1.9). It can effectively lower the winter and summer mortality rates of ark clams, representing an efficacious new methodology for marine shellfish farming.

In this paper, in order to study 650MHz inductive output tube, according to the basic principles of electrodynamics, the influence of the gap and field strength between the cathode and grid, the bias voltage of grid and frequency offset on the modulation density of electron beam is simulated and analyzed, and the verification is carried out by using the three-dimensional electronic optics software.

Saxidomus purpuratus (S. purpuratus) is an economically important bivalve along the northern coast of China, where intensifying fishing pressure threatens its wild stocks. Its genome-wide population genetic variation remains poorly characterized. We resequenced 75 wild individuals from five populations spanning the northern Yellow Sea (Donggang, DDDG; Ganjingzi, DLGJ; Huancui, WHHC) and the Bohai Sea (Changdao, YTCD; Laizhou, YTLZ). The sampled populations exhibited relatively low genetic diversity (He = 0.1301–0.1324), weak among-population differentiation (Fst = 0.0035–0.0040), and heterozygosity deficiency (Fis = 0.0480–0.0831). PCA, NJ, and ADMIXTURE detected no geographic structure. PSMC revealed concordant demographic histories, with a sustained decline following a Middle Pleistocene expansion, consistent with historical allele exchange. Selection scans (DDDG as the target population; WHHC and YTCD as references) identified 1268 candidate genes, of which 197 were shared across the two comparisons. After masking a tandem histone gene cluster, the remaining 155 non-histone genes fell into five functional categories: receptor and signal transduction, membrane transport and ion channels, innate immunity and defense, extracellular matrix and adhesion, and detoxification and metabolism. These signals recurred in both comparisons, identifying DDDG as a candidate population for genotype–environment association testing. Together, these results indicate that the five populations constitute a single genetically connected unit, while pinpointing a small set of candidate loci that may underpin local adaptation and should inform stock-enhancement programmes.