Abstract:Hucho taimen and Hucho bleekeri belong to Salmoniformes, Salmonidae. Hucho are a genus of ferocious large cold-water fishes. There are two main distribution areas of H. taimen in China, namely, the Heilongjiang River Basin in the northeast and the Irtysh River Basin in the northwest. Existing research shows that from the early to the middle of the tertiary period, the Heilongjiang River Basin and the Irtysh River Basin were connected by a vast lake group distributed in northern China and Mongolia. Based on this geographical condition, the H. taimen in the two basins could freely communicate and diffuse in this period. After the middle of the tertiary period, the rivers and lakes connecting the Heilongjiang River Basin and the Irtysh River Basin shrank, and the gene exchange between the two basins stopped as the two basins became geographically isolated. H. bleekeri is an endemic species in China and the species with the lowest distribution latitude among the five species of Hucho. During the quaternary glacial period, the climate of Sichuan Province, Shaanxi Province, and Qinghai Province became cold, and H. bleekeri ancestors moved south from the northern region with a high latitude to the Yangtze River Basin. After the end of the ice sealing period, they stayed in the rivers with high altitudes and low water temperatures, and gradually evolved into the existing H. bleekeri, which is considered as a living fossil for studying the relationship between fish evolution and climate change. To determine the internal and external morphological variation between the rare and endangered H. taimen and H. bleekeri, H. taimen from Xinjiang Uygur Autonomous Region and Heilongjiang Province and H. bleekeri from Shaanxi Province were used as the research object. Nine segmented characteristics and 35 standardized measurement characteristics of the three populations were statistically analyzed using the traditional morphological method and the frame measurement method. The results showed that there was a significant difference in the mean number of lateral line scale between the two geographical populations of H. taimen (P＜0.05), but as a whole, the two populations of H. taimen had individual crossover in all nine segmented characteristics, which could not be distinguished. The average number of dorsal fin branched fin-ray, lateral line scale, and pyloric caecum of H. bleekeri was significantly lower than that of H. taimen (P＜0.05), and there was no individual crossover between these three parameters, so the distinction was obvious. Four principal components with eigenvalues greater than 1 were screened out using principal component analysis, with a cumulative contribution rate of 88.928%, of which the first principal component had the highest contribution rate, which mainly explained the difference in trunk oblique morphology of the three groups. Constructing the two-dimensional scatter plot of principal components, it was found that although the three groups can form relatively independent groups, there were still individual intersections among them, which indicated that the difference in measurement characteristics of the three groups couldn’t be described simply by any two principal components, and all principal components should be considered comprehensively. One-way ANOVA showed that there were only 14 significant differences (P＜0.05) in the measurement characteristics mainly describing the head and tail of H. taimen, while there were 29 significant differences (P＜0.05) in the measurement characteristics mainly describing the trunk between H. taimen and H. bleekeri. A total of 10 measurement characteristics were screened out by discriminant analysis to establish Fisher linear discriminant function, and the discriminant rate of individuals being correctly classified into their respective populations was as high as 100%. Cluster analysis showed that the two geographical groups of H. taimen had the closest genetic relationship, and the genetic relationship between H. bleekeri and the H. taimen from the Xinjiang Uygur Autonomous Region was closer than that of Heilongjiang Province. The comprehensive analysis shows that: (1) there were some morphological differences between the two geographical groups of H. taimen, but they still belong to the same species; and (2) the morphological variations between H. taimen and H. bleekeri were concentrated in the trunk. The segmented characteristics such as the dorsal fin branched fin-ray, lateral line scale, and pyloric caecum could be used as the identification characteristics of the two species. H. bleekeri might have evolved from H. taimen from the Xinjiang Uygur Autonomous Region.

Abstract:With the rapid development of integrated farming of tilapia, various metabolic diseases such as nutritional fatty liver disease are becoming increasingly serious. Severe fatty liver can cause liver failure and cause death in tilapia. It is particularly important to understand the mechanism of lipid metabolism in patients with fatty liver disease. Zebrafish, as a model animal for developmental biology research, is also a research hotspot for liver disease models. Stearoyl-CoA desaturase (SCD) is a key rate-limiting enzyme for MUFA, which plays an important role in regulating hepatic lipogenesis, fatty acid metabolism, and lipid oxidation. Therefore, it is important to study the regulatory mechanism of the scd gene in lipid metabolism in fish. In this study, the complete scd cDNA sequence of GIFT was cloned by RACE and qRT-PCR was used to analyze tissue expression characteristics. To verify the function of scd, an scd knockout zebrafish model was constructed using CRISPR/ Cas9 technology, and the phenotypic and gene expression changes of F3 mutants were studied, and the response mechanism of zebrafish lipid metabolism after scd deletion was verified in combination with high-fat diet experiments. The results showed that the cDNA full-length sequence of the scd gene of GIFT was 1,333 bp in length, including 173 bp at the 5′-UTR, 152 bp at the 3′-UTR, and a 1,008 bp open reading frame (ORF) encoding 335 amino acids. The scd gene was expressed in all tissues of male and female GIFT, with the highest expression in the liver and the lowest expression in the spleen. An scd knockout zebrafish model was constructed using CRISPR/Cas9 for functional validation, and the SCD^(–/–) zebrafish had a significantly enlarged abdomen compared to the SCD^(+/+) zebrafish. Western blot and qRT-PCR results showed that scd gene expression was significantly lower (P＜0.05) in zebrafish from the SCD^(–/–) group compared with zebrafish from the SCD^(+/+) group, and SCD protein expression abundance was also significantly lower (P＜0.05) in zebrafish from the SCD^(–/–) group. Under high fat dietary feeding, the red lipid droplets in the liver tissue cells of zebrafish in the HFD+SCD^(–/–) group were significantly reduced compared to those in the HFD+SCD^(+/+) group. The qRT-PCR results showed that scd mRNA expression was significantly lower in zebrafish in the SCD^(–/–) group compared with zebrafish in the SCD^(+/+) group after scd knockdown (P＜0.05), while lpl, fas, and hsl mRNA expression were significantly higher in the liver of zebrafish in the SCD^(–/–) group (P＜0.05). Compared with the zebrafish fed the control diet, zebrafish fed with the high-fat diet had significantly increased expression of scd mRNA in liver and inhibited the expression of fas mRNA (P＜0.05). The results also suggest that scd gene knockdown can alleviate liver fat deposition in zebrafish caused by high fat diets, and that the scd gene may play an important role in fatty acid metabolism and lipid synthesis in fish.

Abstract:Chinese sturgeon (Acipenser sinensis) is a key protected animal at the national level in China. At present, large-scale breeding of the second generation of Chinese sturgeon has been preliminarily realized. This has significantly increased the pressure on the cultivation of the facilities of various Chinese sturgeon protection institutions. Therefore, it is important to study the suitable stocking density of adult Chinese sturgeon without affecting gonadal development to make the best use of the cultural facilities. To study the suitable stocking density of adult Chinese sturgeon [(5.61 ± 0.61) kg], three density gradients (low, middle, and high) were set up in this experiment, and the initial densities were (6.12 ± 0.04) kg/m³ , (8.92 ± 0.19) kg/m³ , and (11.75 ± 0.29) kg/m³ , respectively. After 12 months of culture, the experimental fish were transferred to the recovery pond [(4.11 ± 0.03) kg/m³ ] and re-cultured for 6 months. The growth, blood biochemical, and sex hormone levels were measured at 0, 12, and 18 months. The results showed that the densities of low, medium, and high density groups were (10.99± 0.21) kg/m³ , (13.59 ± 0.10) kg/m³ , and (17.78 ± 0.28) kg/m³ at 12 months, respectively. With the increase of designed stocking density, the body weight, specific growth rate (SGR), weight gain rate (WGR), and daily weight gain rate (DWGR) of experimental fish decreased significantly (P ＜ 0.05), while the body weight variation coefficient and feed coefficient (FCR) increased significantly (P ＜ 0.05). The concentrations of serum triglyceride (TG), total cholesterol (TC), and total protein (TP) decreased with the increase of designed stocking density. The concentration of blood glucose (GLU) in the high density group was higher than that in the middle and low density groups (P ＜ 0.05). There was no significant difference in the concentration of albumin (ALB) among the groups. The concentrations of 17α, 20β-dihydroxyprogesterone (17α, 20β-DHP) and testosterone (T) in each density group were not significantly different, but their concentrations were slightly higher than those at the beginning of the experiment. The levels of estradiol (E2), vitellogenin (VTG), and progesterone (P) in the high density group were significantly lower than those in the low and middle density groups (P ＜ 0.05), and there was no significant difference between the low and middle density groups. Differences in body weight, condition factor (CF), and coefficient of variation of body weight among different density groups were smaller than that at the beginning of the recovery period. The concentrations of GLU, ALB, TG, TC, and TP in each density group recovered to the level at the beginning of the experiment, and there was no significant difference among the three groups. The concentrations of E2, VTG, and P in each density group recovered to the same level, and there was no significant difference among the groups. The results showed that high-density culture had significant negative effects on growth and sex hormone levels of adult Chinese sturgeon but had no significant effects on medium-density and low-density groups. To maximize the utilization of culture facilities, some growth performance can be appropriately discarded on the premise of ensuring the normal development of gonads of adult Chinese sturgeon. Therefore, it is suggested that the real-time stocking density of adult Chinese sturgeon should not exceed 13.59 kg/m³ .

Abstract:Curcumin is a natural yellow pigment derived from turmeric and tulip rhizome, has been widely used as feed additives to improve the health of cultured animals due to its highly biologically active and functions of anti-inflammatory, antioxidant, and blood lipid-lowering. However, the application of curcumin is rarely studied in sturgeon, which is intensively cultured because of the high value of nutritional and economic. Therefore, to investigate the effect of curcumin on the growth and health of sturgeon, a 6–week feeding trial was conducted using hybrid sturgeon (Acipenser baeri♂×Acipenser schrenckii♀). A total of 300 juvenile hybrid sturgeon with an initial weight of (16.24±0.11) g were assigned to diets containing 0 g/kg, 0.025 g/kg, 0.05 g/kg, 0.1 g/kg and 0.2 g/kg curcumin in triplicated. The results showed that the addition of curcumin in the feed had no significant effect on the growth performance and body composition of juvenile hybrid sturgeon. Curcumin addition significantly decreased serum TG content in the group of 0.2 g/kg curcumin in diets (P＜0.05), ALT and AST activities in hybrid sturgeon liver were reduced with the curcumin level increasing, which appeared significant difference with control at the curcumin level at 0.2 g/kg and 0.05 g/kg, respectively (P＜0.05). Curcumin significantly improved the activity of protease in duodenum with curcumin level increasing at first, which showed the highest activity at 0.05 g/kg of curcumin supplementation respectively (P＜0.05), and then decreased with curcumin further increasing. Curcumin addition improved the activity of α-AMY significantly at 0.1 g/kg of curcumin supplementation respectively (P＜0.05), and then decreased. The results of antioxidants showed that serum MDA content decreased significantly in the group of 0.025 g/kg curcumin (P＜0.05), in which group serum CAT activity increased significantly (P＜0.05). While a significant increase of CAT activity in the liver appeared in the curcumin addition level at 0.05 g/kg (P＜0.05). There was no significant difference among the treatments even though decreased MDA content and increased SOD activity appeared in the liver. MDA content, SOD and CAT activities in duodenum showed a similar change pattern with that in serum, however, no significant effect was observed by curcumin addition. Histopathology results of duodenum indicated that curcumin addition in feed could improve the structure of intestine, which showed clear and fewer adherent villi structures. The present study indicated that the appropriate curcumin supplementation in feed was beneficial to the health of hybrid sturgeon, which could improve the antioxidant capacity of the fish, promote the health of liver and intestine, in the meantime, decrease the lipid. In conclusion, according to the current study, the addition of 0.025–0.05 g/kg of curcumin was suggested in hybrid sturgeon diets. This study could provide scientific basis for curcumin supplementation in sturgeon feed, ultimately help the health development of sturgeon aquaculture.

Abstract:By adding rehmannia powder or Chinese yam powder into the high-lipid diets of Cyprinus carpio haematopterus, this study was conducted to investigate whether Chinese herbal medicine additives could improve the adverse effects of a high lipid diet on the growth and physiology and lipid metabolism of fish. A total of 360 healthy Cyprinus carpio haematopterus with an initial body mass of (79.97±9.86) g were randomly divided into 4 groups: the control group (NC), high lipid group (HLD), rehmannia added group (HLD+R), and yam added group (HLD+Y). The fish were fed with a basal diet, high fat diet (fat content 14%), high fat diet + 4% rehmannia powder and high fat diet + 2% yam powder, respectively. A 12-week feeding trial was performed, and all the fish were fed to satiety during the first 3 weeks. Then, the fish were fed at the same feeding rate during the subsequent breeding period. Samples were taken at the end of 3, 7, and 12 weeks to detect growth and serum biochemical parameters, hepatopancreas fat content, and lipid metabolism-related gene expression levels. The results showed that the growth rate of C. carpio haematopterus was decreased by the HLD diet, and this effect had a significant effect at the end of the 7th week (P＜0.05). In contrast, the addition of rehmannia powder or Chinese yam powder in the HLD diet could inhibit this effect. Serum activities of alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were significantly increased by the HLD diet (P＜0.05), and the activities of ALT in serum were significantly decreased by rehmannia powder or Chinese yam powder, but had no effect on ALP activity (P ＞ 0.05); the activity of lactate dehydrogenase (LDH) in the HLD group and HLD + R group was significantly lower than that in the NC group after the first 3 weeks of full feeding (P＜0.05), after which there was no significant difference between groups. HLD diet increased blood lipid and liver lipid content, while rehmannia or yam can significantly decrease blood lipid, especially serum triglyceride content. There was no significant difference in the expression of lipid metabolism related genes in the hepatopancreas among the four groups in the first 3 weeks. After that, the expression of Fas, Acc1 and Ppar-α genes increased significantly in the HLD group (P＜0.05). The addition of rehmannia powder or yam powder significantly inhibited the increase of Acc1 and Fas levels induced by the HLD diet (P＜0.05), however, their inhibitory effect on Ppar-α expression was not significant; and the expression levels of Cpt-1 and Lpl genes in the HLD group were significantly lower than those in the NC group at the end of the 7th week (P＜0.05), and higher than that in the NC group at the end of the 12th week. The expression of these two genes was significantly up-regulated by adding rehmannia powder or yam powder in the HLD diet (P＜0.05). Therefore, high dietary lipid level can inhibit the growth of C. carpio haematopterus and affect the activity of serum enzymes and may lead to elevation of blood lipid and liver fat accumulation by affecting the expression of lipid metabolism related genes in the hepatopancreas; the addition of rehmannia or yam can counteract the adverse effects caused by an HLD diet.

Abstract:Blood clam (Tegillarca granosa), as a common farmed bivalve in tidal flat shellfish, has high economic value. Conditional pathogenic bacteria, such as Vibrio, is a serious problem encountered in the healthy culture of bivalve shellfish. To explore the role and mechanism of JNK-mediated AP-1 innate immune defense pathway in the process of vibrio infection, the cDNA sequence of TgJNK was cloned by PCR, and the expression and regulatory relationship of TgJNK and TgAP-1 after vibrio infection were analyzed. The results showed that the fulllength of the TgJNK cDNA sequence was 2696 bp with an open reading frame of 1,332 bp, encoding a 443 amino acid polypeptide. Multiple protein comparison and adjacent phylogenetic tree analysis showed that TgJNK was relatively conservative with a STKc-JNK domain and had high homologous similarity with Crassostrea gigas and Mytilus edulis. The qRT-PCR and WB analysis showed that TgJNK was highly expressed in the gill. The level of TgJNK transcription was up-regulated significantly (P＜0.05) with immersion infection of Vibrio harveyi. At the same time, the phosphorylation level of TgJNK and the abundance of TgAP-1 protein increased under the stimulation of vibrio. The effect of the JNK inhibitor could significantly decrease the transcription level of TgJNK and TgAP-1(P＜0.05). Correspondingly, the phosphorylation of TgJNK and the abundance of TgAP-1 protein decreased after JNK inhibition. In addition, CoIP analysis showed that the phosphorylated JNK protein could bind to TgAP-1 protein. These results indicated that TgJNK and TgAP-1 participated in the innate immune response of Vibrio infection in blood clams. The phosphorylation of TgJNK protein was an important factor in activating TgAP-1 protein, and TgJNK could positively regulate the expression of TgAP-1. The study elucidated the signal transduction mechanism of JNK-mediated AP-1 pathway after vibrio infection and enriched the theoretical knowledge on the innate immunity of bivalve shellfish.

Abstract:Cadmium (Cd) is a highly toxic heavy metal element which has a long half-life and is difficult to degrade. Even at very low concentrations, it can cause great damage to fish. Peroxisome proliferator activated receptor-γ co-activator-1 (pgc1) is a transcriptional co-activator that coordinately regulates the activities of PPARγ, plays an important regulatory role in energy metabolism, mitochondrial biosynthesis, and antioxidative system in organisms. In this study, the cis-regulatory elements, sequence characteristics, evolutionary relationship, tissue expression characteristics of pgc1α and pgc1β gene promoter in Chinese perch, and the circadian rhythm of pgc1α and pgc1β genes in brain exposed to cadmium were analyzed. The results showed that NF-E2 and IRF1 binding sites existed in the promoter of pgc1α and pgc1β, and KLF9 binding sites existed in the promoter of pgc1β. Both pgc1α and pgc1β genes contained a complete LXXLL motif and RRM domain. Chinese perch pgc1α and pgc1β shared 51.6% and 59.7% homology with zebrafish and 41.5% and 28.4% homology with human homologous genes, respectively. The expression of pgc1α and pgc1β genes in Chinese perch has obvious tissue specificity, and are highly expressed in the brain, kidney, and heart. Under natural conditions, the expression of pgc1α and pgc1β in Chinese perch brain showed a trend of being high in the day and low in the night, and the peak phase of gene expression was ZT 7.07 h and ZT 8.25 h, respectively. The diurnal variation of pgc1α and pgc1β gene expression in Chinese perch brain was reduced and the amplitude was decreased under heavy metal cadmium stress. The peak phase of gene expression was advanced to ZT 3.71 h and ZT 5.65 h, respectively, indicating that cadmium exposure causes a significant disturbance on the circadian rhythm of pgc1α and pgc1β in Chinese perch brain.

Abstract:Habitat suitability assessment is an important prerequisite and basis for assessing biological resources and protecting biodiversity. Based on the survey data of macrobenthos and environmental factors in the summer, autumn, and winter of 2020 in the mangrove of Yanpu Bay, we have studied the habitat suitability of macrobenthos. In this study, Cerithidea largillierti, the dominant species of macrobenthos, was selected as the research object. A Generalized Additive Model was used to screen environmental factors, and the relative weight method was used to determine the weight of environmental factors. Then, the habitat suitability model was established by using the Weighted Average Model and Geometric Mean Model, respectively, and the optimal model was established based on cross check and Akaike Information Criterion (AIC). The results showed that the Habitat Suitability Index model based on Geometric Mean Model was the best fit model, and temperature, ammonia nitrogen, reactive phosphate, dissolved oxygen, electrical conductivity, nitrite, pH, and nitrate with the minimum AIC value were selected as explanatory variables. The temporal Habitat Suitability Index showed that autumn ＞ summer ＞ winter. The spatial Habitat Suitability Index showed that offshore section ＞ middle section ＞ nearshore section, northwest section ＞ southeast section. The results showed that there was obvious spatial and temporal heterogeneity in the habitat suitability of C. largillierti in the mangroves of Yanpu Bay. The findings may be used to raise awareness among researchers and policymakers. In addition, more comprehensive and scientific surveys will help to better understand the habitat suitability of macrobenthos in the future.

Abstract:The regulation of the carbon-to-nitrogen ratio (C/N) is the core technical feature of biofloc culture. In related research and practice, carbon and nitrogen in C/N have different characterization forms. In this study, dissolved organic carbon (DOC) was used to characterize the organic carbon using total nitrogen (TN), dissolved inorganic nitrogen (DIN), and total ammonia nitrogen (TAN) to characterize nitrogen, respectively, and compare the same C/N under different nitrogen form conditions. The ammonia nitrogen removal capacity, basic nutrient components, functional genes related to nitrogen metabolism, and the total number of heterotrophic bacteria of the lower biofloc were evaluated. In the experiment, the DOC/TN of group A was 20, the DOC/DIN of group B was 20, and the DOC/TAN of group C was 20. In each experimental group, 10 mg/L ammonia nitrogen could be reduced to less than 1 mg/L within 8 hours, and the TAN removal rates were (2.11±0.05) mg TAN/gTSS·h, (2.00±0.02) mgTAN/gTSS·h, and (2.09±0.02) mgTAN/h, respectively. The removal rates of group A was significantly higher than group B (P＜0.05), and there was no significant difference between group C and groups A and B (P＞0.05). There was no significant difference in the crude protein content of flocs among each group. The crude fat content of flocs in group C was significantly higher than that in groups B and A (P＜0.05), and the content of major amino acids and fatty acids was not significantly different (P＞0.05). The abundance of denitrification function genes narG, napA, nirS, and nosZ in flocs in each group ranged from 2.2×10⁶ to 4.7×10⁷ copy/mL. The napA gene in group A was significantly lower than that in group B. The nirS gene was significantly lower than that in group B and C (P＜0.05) and there was no significant difference between group B and group C (P＞0.05). There was no significant difference in the nosZ gene copy factor (P＞0.05). The total number of heterotrophic bacteria and Vibrio in group C were significantly lower than those in groups A and B (P＜0.05). This study shows that adding carbon sources according to different nitrogen forms has an overall effect on the ammonia nitrogen treatment efficiency, function, and nutrient composition of bioflocs within the acceptable range of production. Considering the feasibility of actual operation, it is recommended that the total ammonia nitrogen concentration estimate the amount of carbon source addition required.

Abstract:To understand the temporal and spatial distribution characteristics of the early resources of Siniperca chuatsi (Basilewsky) in the lower reaches of the Xiangjiang River and their correlation with habitat characteristics, the early resources of the Siniperca chuatsi were sampled every other day using cone nets in the Changsha section of the Xiangjiang River from May to July in 2020 and 2021. Statistical analysis of the S. chuatsi seedling growth stage, water distribution, and time distribution of the hydrological environment factors was conducted. The main breeding period in the Xiangjiang River was studied and the hydrologic characteristics of seedling height were used to calculate the fish group's ability to escape the cone net. Redundancy analysis (RDA) was used to analyze the association between S. chuatsi fry abundance and environmental factors. The results showed that the peak breeding period of S. chuatsi in the Xiangjiang River was from mid-May to late June, and the spawning grounds were scattered and varied in size. The surface layer is larger than the middle and lower layers (P＜0.05), but the yolk sac stage larvae are more inclined to the middle and lower layers, and the distribution difference is mainly caused by its swimming ability and flow velocity. There was no structural fry escape phenomenon. The reproduction of Siniperca chuatsi in the Xiangjiang River was mainly stimulated by floods, and the abundance of fry was positively correlated with water temperature (P＜0.05) and negatively correlated with transparency (P＜0.05). The water temperature during the peak breeding period was between 19.3 and 28.0 ℃ and the transparency was less than 30 cm. At present, the water temperature, transparency, flow rate, and dissolved oxygen in the Xiangjiang River all meet the requirements of S. chuatsi breeding habitats. In 2021, the abundance of S. chuatsi fry was more than twice that of 2020, which is an important reason for the recovery of the feed fish resources or the improvement of the reproductive capacity of S. chuatsi population. It is suggested that, to further strengthen the early resource protection and monitoring of S. chuatsi and other fish in the waters of the Xiangjiang River, promoting the restoration of the ecological stability of the fish community is necessary. In addition, full play must be accorded to its role in supplementing fish resources in the waters of Xiangjiang-Dongting Lake-Yangtze River.

Abstract:This study aimed to explore the growth heterogeneity and evaluate resource development status of Sebastes schlegelii in three artificial reef areas (Changdao reef area, Xixiakou reef area, and Qiansandao reef area) in coastal Shandong from 2017 to 2021 based on ocean environment and resource survey data. The ELEFAN method of Bootstrap was used to explore the growth characteristics of S. schlegelii, the Length-Converted Catch Curve was used to explore the death characteristics of S. schlegelii, the linear mixed-effects model was used to study the spatial and temporal heterogeneity of body length-weight relationship of S. schlegelii, and the Beverton–Holt model and exploitation rate were used to explore the resource utilization of S. schlegelii. The results showed that the growth condition factor (a) of S. schlegelii in the Qiansandao reef area was significantly higher than that in the Xixiakou and Changdao reef areas. The asymptotic body length and asymptotic body weight of S. schlegelii in the Qiansandao reef area were the largest, followed by those of the Xixiakou and Changdao reef area. The total death coefficient and natural death coefficient of the Changdao reef area were 0.87 and 0.44, respectively, which were higher than those of the Xixiakou and Qiansandao reef area; the parameters a and b obtained using the linear mixed-effect model ranged from 1.48×10^–5 to 5.92×10^–5 and 2.85 to 3.13, respectively. With the same body length conditions, the individual quality of S. schlegelii in the spring and autumn of 2020 was the highest in the Qiansandao reef area, followed by the winter of 2021, 2018, and 2017 in the Xixiakou reef area; the summer of 2019 in the Changdao reef area was the lowest. The exploitation rate conformed to the mild development indicators of the Gulland theory, and the Beverton–Holt model showed that the fishing current points of the three reef areas were all located in the optimum yield area, but close to the edge of the optimum yield area; thus, the fishing intensity should be controlled.