Abstract:The Yangtze finless porpoise (Neophocaena asiaeorientalis, YFP) has attracted much attention because of the dramatic decline in population size over the past decades, which raises the concern of extinction. Exploring the immune adaptability that occurs between female and male YFPs is important for their protection. In this study, blood samples of 3 female and 3 male YFPs were used for mRNA and miRNA sequencing by RNA-seq technology. We systematically investigated the mRNA and miRNA profiles of female and male YFPs to screen for genes, pathways, and predicted miRNA-mRNA networks associated with the immune system. A total of 15878 unigenes and 985 microRNAs were obtained from 6 samples. KEGG analysis revealed that 1534 unigenes were annotated to the immune system category and were significantly (P＜0.05) enriched in 20 common immune pathways. Further, 539 differentially expressed genes (DEGs) and 160 differentially expressed miRNAs (DEMs) were identified, of which 299 were female-preferred genes and 240 were male-preferred genes. GO and KEGG enrichment analysis showed that blood genes were significantly correlated with immune response and energy metabolism in females, and with immune response and cell growth in males. In addition, pathway enrichment analysis revealed that FoxO and Hippo signaling pathways were activated in the female blood. Based on the integrated analysis of DEGs and DEMs, 45 negative regulatory relationships of miRNA-mRNA were predicted, including 13 DEMs and 37 immune-related DEGs. Studies have shown that microRNAs are involved in the immune system of both female and male YFPs by regulating gene expression, and adult female YFPs may have stronger immunity and the ability to maintain homeostasis. This study provides a new perspective for interpreting the adaptability of male and female YFPs to diverse habitats from the perspective of immunity, and the study’s findings are of great significance for protecting this endangered species.

Abstract:In this study, the complete mitochondrial genome of Ophichthus evermanni was obtained by high-throughput sequencing. The results of structure and characteristics analysis showed that the total length of the complete mitochondrial DNA was 17759 bp, including 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNA), 2 ribosomal RNAs (rRNA), 2 control regions (D-loop), and 1 origin of the L-strand replication region (OL). The base composition of the complete mitogenome of O. evermanni was A (31.27%), G (16.19%), C (26.22%), and T (26.32%). The A+T content (57.59%) was greater than the G+C content (42.41%), showing an obvious A+T bias. Unlike other typical teleosts, the gene arrangement was identified in the mitogenome of O. evermanni. The ND6 gene and the conjoint tRNA-Glu were translocated between tRNA-Thr and tRNA-Pro, and another highly homologous D-loop region was located upstream of the ND6 gene. The tRNA-Gln (Q), tRNA-Ala (A), tRNA-Asn (N), tRNA-Cys (C), tRNA-Tyr (Y), tRNA-SerUCA (S1), tRNA-Glu (E), tRNA-Pro (P), and ND6 were located in the L-strand, whereas the remainder were located in the H-strand. Except for tRNA-Ser (AGC), the remaining 21 tRNAs could fold into the typical cloverleaf secondary structure. The phylogenetic relationships of Ophichthidae fishes were constructed based on 12 protein-coding genes (excluding ND6) using the neighbor-joining and Bayesian methods. The results suggested that O. evermanni was closely related to O. brevicaudatus and Pisodonophis cancrivorus, and genetic divergence occurred in the genus Ophichthus, which was relatively late among the family Ophichthidae. The results will supplement the mitochondrial genome database of the family Ophichthidae and also provide a reference for the taxonomic study of snake eels.

Abstract:To explore the genetic structure and variation of the current largemouth bass (Micropterus salmoides) population, mitochondrial D-loop sequences and 14 simple sequence repeat (SSR) markers were used in this study. A total of 175 individuals from three cultured populations (“China-Taiwan” CTW, “YouLu1” YL1, “YouLu3” YL3), one breeding population (northern subspecies, US) and one “Hybrid population” (northern subspecies♂ × “YouLu 3” ♀, HYB) were analyzed for genetic variation. The results showed that all 14 microsatellite loci could be effectively amplified, and five loci (LMB24, LMB28, LMB38, LMB39, and LMB42) showed high polymorphism (PIC＞0.5). The highest polymorphism level was detected in the US population (PIC=0.514), whereas the polymorphism levels of the other four populations were lower (0.278＜PIC＜0.359). Based on D-loop sequencing, 23 mutation sites and 23 haplotypes were detected, and the haplotype diversity of the 5 populations ranged from 0.218 to 0.882. Abundant haplotypes (n=12) were detected in the US population. The dominant haplotype (H01) was detected in the other four populations, with contributions ranging from 76.7%–85.7%. Analysis of genetic variation based on SSR and D-loop sequences showed that Nei’s genetic distance and K2P genetic distance (0.3003 and 0.012, respectively) between the US and YL3 populations were the farthest (0.300 and 0.012, respectively), which where greater than those among other populations (0.016–0.297 and 0.000–0.012, respectively). Molecular analysis of variance showed that the genetic differentiation of the five largemouth bass populations was highly significant (P＜0.01). The results of the genetic structure and haplotype network analysis suggested that relative genetic independence was exhibited in the US population, whereas similar genetic resources were found in other cultured populations. The results showed that the newly introduced US population maintained a high level of genetic diversity and showed significant genetic differentiation from the domestic breeding populations. In conclusion, selective breeding of the US population and/or their crossbreeding with other populations has better prospects for genetic improvement.

Abstract:The yellowtail kingfish (Seriola lalandi) is a globally distributed pelagic migratory fish species. It is considered a promising species for the aquaculture industry worldwide because of its high flesh quality and fast growth. Therefore, the demand for yellowtail kingfish has increased in recent years, which has caused overfishing and a drastic decline in natural resources. Large-scale farming started in 2017 as seedlings production technology was established in China. Practice has proved that farming this species is suitable in both net cages and industrial farming systems. With the growth of the scale of farming, it is urgent to determine the key parameters, including the suitable stocking density and other factors, to establish an efficient technology for industrial farming. The stocking density of marine animals is a critical parameter in aquaculture management. A suitable density could reduce the stress level of the farmed animals, which will be beneficial to good health and rapid growth. To investigate the optimal density of yellowtail kingfish in land-based industrial farming, this study was conducted in 6 circular glass buckets for 60 d. The effective water volume of each circular glass bucket was 3 m³ , and these buckets were divided equally into three density groups: 10 fish/m³ (low-density group), 20 fish/m³ (mediumdensity group), and 30 fish/m3 (high-density group). After domestication, healthy 1 year old yellowtail kingfish [(565.83±70.22) g] were distributed into three density groups according to the density rule. The water temperature was 22–27 ℃, salinity was 29–32, and the dissolved oxygen was higher than 6 mg/L during the experiment. During this experiment, the growth performance indicators, including weight gain ratio (WGR), specific growth ratio (SGR), condition factor (K), and hepatosomatic index (HIS) were measured and calculated, and indicators, such as blood physiology (e.g., white cell number, red cell number, hemoglobin), serum biochemistry (e.g., epinephrine and cortisol content), and the non-specific immune enzyme activity of the liver and kidney tissues [e.g., activities of superoxide dismutase (SOD) and lysozyme (LZM)] were detected. The results showed that the WGR and SGR of yellowtail kingfish in medium and high-density groups were significantly lower than those in the low-density group at 60 d (P＜0.05). The SGR of the low-density group at 60 d was significantly higher than that at 30 d (P＜0.05). However, there was no significant difference in the SGR of the medium-density group between 60 d and 30 d (P＞0.05). Moreover, the SGR of high-density group at 60 d was lower than that at 30 d. The changes in these growth performance indices indicated that the higher stocking density had been stressful to the growth of yellowtail kingfish. During the entire experiment, the contents of epinephrine and cortisol in the serum increased significantly at 30 d and 60 d with the increase of stocking density (P＜0.05), whereas the contents of growth hormone (GH) and insulin–like growth factor I (IGF–I) in serum showed the opposite trend. The activities of SOD, AZM, ALT, AST, ACP, AKP, and PK exhibited a trend of increasing significantly at 30 d and 60 d with the increase of stocking density (P＜0.05). The changes in these physiological and biochemical indicators showed that the higher stocking density created stress on the physiology of yellowtail kingfish. Therefore, from the perspective of growth, physiology, and production practice, the low-density group (20 fish/m³ ) is the appropriate density for the industrial farming of 1 year old yellowtail kingfish. The relative results provide a basic reference for further improvement of industrial farming technology for yellowtail kingfish.

Abstract:Costaria costata is a new large economic brown alga with potential. Mastering the suitable conditions for its growth and development and its regulation mechanism is the premise of developing the cultivation industry. At present, reports have focused on the gametophyte stage, and temperature is one of the most critical factors affecting algal growth and development. In this study, we investigated the growth and antioxidant physiological characteristics of young sporophyte of C. costata at 6–22 ℃ in order to explore its temperature-adaptation mechanism and provide a theoretical basis for the cultivation of C. costata in sea areas. At the early stage of culture (within 5 days), the relative growth rate (RGR) of young sporophyte of C. costata was the largest at 18 ℃, and the algae were severely perforated and rotted at 22 ℃; with the extension of culture time (10 days), the RGR of algae was the highest at 10 ℃. There was no significant difference in F_v/F_m at different temperatures. During the experimental period, the total photosynthetic rate (P_t) and net photosynthetic rate (P_nmax) of algae were higher at 6–14 ℃. P_nmax was highest at 10 ℃ at 5–10 d. Respiration rate (R_d) was highest at 6 ℃ at 3 d. Algal R_d increased with culture time at 22 ℃. Enhanced respiration is a common response of the young sporophytes of C. costata to low and high-temperature stresses. At 22 ℃, the pigments Fucox and Car, soluble proteins play an active role. At 6 ℃, SOD is the main antioxidant enzyme that scavenges reactive oxygen species. Temperature positively regulates the accumulation of ash, carbohydrate, and crude fiber in the range of 6–18 ℃. In summary, the young sporophytes of C. costata can grow at 6–18 ℃, of which 10 ℃ is preferable.

Abstract:Large-scale cultivation of Gracilaria lemaneiformis developed in the Nan’ao area, Shantou, Guangdong Province in 2005. Nan’ao Island is an important base for Gracilaria cultivation in China. This survey was conducted in a re-planning culture area of the G. lemaneiformis cultivation system in Nan’ao. Samples of water, sediment, cultivated Gracilaria, and their litter were collected from the seaweed cultivation area (G). The current Gracilaria cultivation area is a mixed cultivation area of shellfish and algae, where oyster culture has been performed for many years. Samples were also collected from the adjacent control area (C) when the seaweed exhibited the largest biomass. The results showed that the amounts of bacteria were 3.96×10⁵ copies/mL and 4.97×10⁵ copies/mL, respectively, in the surface and bottom water of the G area. They were significantly higher than that in the C area. However, sediment bacteria showed no significant differences between the G and C areas. The densities of sequenced bacteria and cultured bacteria on the Gracilaria surface were significantly higher than that in their litter. Among different habitats (water, sediment, and G. lemaneiformis), bacterial diversities of the two areas were higher in the sediment. Compared with the C area, the relative abundance of Bacteroidetes and Firmicutes was higher in the sediment of G area. For water samples, the dominant bacteria were similar between those two areas, but a higher relative abundance of Rhodobacteraceae was observed in the G area. The main dominant genus attached to Gracilaria and their litters were Geitlerinema, Vibrio, and Pseudoalteromonas. Correspondingly, Vibrio alginolyticus, Vibrio cyclitrophicus, and Pseudoalteromonas sp. were isolated and identified among the culturable dominant bacteria. Through the redundancy analysis (RDA), pH, DO, and salinity were the dominant factors affecting bacterial community compositions in water and on the surface of G. lemaneiformis. Total phosphorus (TP) was the dominant factor affecting bacterial community composition in sediments. The results indicated that large-scale cultivation of G. lemaneiformis plays an important role in the assembly of bacterial communities in both the water body and sediment in the seaweed cultivation ecosystem. Furthermore, the surface of cultivated Gracilaria and its litter had specific microflora, which may affect the structure and function of the seaweed cultivation ecosystem.

Abstract:It is vital to study the spatial distribution characteristics and formation mechanism of biodiversity to enable its conservation. However, how spatial changes affect fish community structure is controversial. The Yarlung Zangbo River is the highest river in the world and nurtures the most distinctive plateau ecosystem and fish resources worldwide. The Yarlung Zangbo River Grand Canyon is located in the lower reaches of the Yarlung Zangbo River and is the deepest canyon in the world. Due to the complex topography and inconvenient transportation in the Yarlung Zangbo Grand Canyon, research on fish community structure and diversity is also unknown in the Motuo reach. This investigation presents the first analysis of the spatial variation in structure and diversity of fish communities in the Motuo reach of the Yarlung Zangbo Grand Canyon. Based on fishery resource survey data in the Motuo reach and Buqun Lake in spring (April) of 2015, and spring (March to April) and autumn (November) of 2017. Spatial variation in the structure and diversity of fish communities in the Motuo reach was determined. The results indicated that 18 fish species were caught, which belonged to 2 orders, 4 families, and 13 genera. There were 2 non-native fish species, including Cyprinus carpio and Pseudorasbora parva. The composition of species has changed compared with historical data. On one hand, there were some differences in the results caused by different classification and identification methods. Historically, morphological identification was primarily used, but molecular genetic methods were used in this study. On the other hand, the fishing methods and intensity were different. Electric capture was used for the first time in this survey. We found three new fish species by morphological and molecular genetics. These new species belonged to Schizothorax, Garra, and Exostoma, and were tentatively named Schizothorax sp., Garra sp., and Exostoma sp., respectively. There was significant spatial variation in species composition between the main stream and its tributaries; the main stream was primarily composed of large- and medium-sized fish, whereas the tributaries consisted primarily of small fish. The predominant species in the fish communities were also different between the main stream and its tributaries; however, Schizothorax curvilabiatus was the dominant species in all water bodies. First, the main factors affecting the composition of the river fish community were the spatial changes in the physical and chemical environment. Second, the variability of environmental factors led to the spatial heterogeneity of fish community structure. Third, the spatial differences in fish composition were also related to their living habits and ecological needs. S. curvilabiatus had the highest relative biomass and abundance. The mean relative resource was 9844.7 g/h by electric fishing, 446 g per gill net in the main stream, and 486.4 g/h by electric fishing in tributaries. The range of Shannon-Wiener diversity index H′ varied from 0.95 to 1.77, and the range of the Margalef species richness index D? was from 0.58 to 1.13, with the Pielou evenness index J? being from 0.37 to 0.77. There was a difference between the main stream and its tributaries according to each diversity index, and all diversity indexes in the main stream were lower than the corresponding indexes in tributaries. The unsuitability of the abiotic environment and the low availability of ecological niches and habitat may be the reasons for the low diversity in this reach and may also have contributed to the difference in the degree to which natural disasters threaten tributaries and main streams and the abundance of the organisms in the feed. This survey aims to provide background information to reveal the evolution of fish resources in the lower reaches of the Yarlung Zangbo River under human disturbance after hydropower development and provide a scientific basis for the protection of fish species diversity and fishery resource management in the Yarlung Zangbo Grand Canyon National Nature Reserve.

Abstract:The feeding ecology of fish is an important part of the study of the marine ecosystem. Through predation, fish not only satisfy their own growth and development but also promote energy flow in the ecosystem. Studies on the feeding habits and trophic interactions of fish can provide a scientific basis for ecosystem-based fishery management. Pennahia argentata and Atrobucca nibe are two common economic fish species in China and belong to the Sciaenidae family. Many studies have been done on these two species, except for the feeding relationship between them. To analyze the feeding habits and trophic interactions between these two species, biological samples for both species were collected based on bottom trawl surveys conducted in the southern coastal waters of Zhejiang in August and November 2020 and January 2021. A total of 287 stomach samples of P. argentata and 204 stomach samples of A. nibe were collected to perform stomach content analyses. The percentage index of relative importance (IRI%) was used to measure the importance of each prey item. Cluster analysis was used to evaluate the ontogenetic variation in their feeding habits. To facilitate the analysis of the relationship between feeding habits and size classes, the samples of P. argentata were divided into eight size classes, and samples of A. nibe were divided into six size classes. The overlap coefficient of diet was used to estimate the overlap of food composition between these two species. The results indicated that the prey items of P. argentata included 48 species, among which, Copepoda was the main prey category and Calanus sp. (IRI%=53.73%) was the dominant prey species. A. nibe fed on 43 species, mainly fish and shrimp, with Benthosema pterotum (IRI%= 65.25%) being the dominant prey species. By feeding on different proportions of prey, these two species ease the feeding competition by having different main prey categories. Furthermore, obvious ontogenetic variations in the feeding habits were observed for both species. With the increase of predator body length, the main prey items switched from small-sized items to large-sized items, and their feeding intensity changed correspondingly. The feeding intensity of P. argentata gradually decreased with body length, while the feeding intensity of A. nibe decreased at first and then increased with body length. Trophic niche breadth indicated the place of a predator in the ecosystem in relation to its prey. The trophic niche breadth of A. nibe (3.06) was much wider than that of P. argentata (1.82), indicating that A. nibe had a better ability and range of utilizing food resources. The overall feeding overlap value between these two species was 0.22, whereas high overlap values occurred in certain body length group combinations. For example, majority of the feeding overlap values between all body length groups of A. nibe and of P. argentata groups with body length in range of 120–159 mm were higher than 0.6, indicating significant feeding overlap. This phenomenon revealed the possibility of feeding competition between P. argentata and A. nibe in the southern coastal waters of Zhejiang. The findings of this study enhanced our understanding of the trophic interaction between P. argentata and A. nibe and provided basic data for ecosystem-based fishery management in the southern coastal waters of Zhejiang.

Abstract:To understand the spatial pattern of fish communities in the adjacent waters of the Changshan Islands in spring and autumn, the spatial structure of fish communities and its relationship with environmental factors in spring and autumn were examined using multivariate statistical analysis, including cluster analysis and MDS, based on data collected from surveys in October 2016 and May 2017. There were 66 species of fish captured in this sea area, belonging to 58 genera, 33 families, and 11 orders, including 46 species in spring and 52 species in autumn, all of which were dominated by Perciformes. The dominant species of fish communities in spring were Enedrias fangi, Lophius litulon, and Thryssa kammalensis. The fish community in spring was divided into two station groups. Station group I was located to the west of the Changshan Islands, and station group II was located in the Changshan Islands and its eastern waters. The bottom water temperature was the main environmental factor affecting the spatial structure of the fish community in spring. The main typifying species in each station group, such as Lophius litulon and Thryssa kammalensis, had apparently different spatial distribution patterns. The dominant species of fish communities in autumn were Chelidonichthys spinosus, Lophius litulon, and Paralichthys olivaceus. The fish community in autumn was divided into two station groups. Station group I was located in the eastern and western waters off the Changshan Islands, and station group was distributed around the Changshan Ⅱ Islands. Water depth and bottom water temperature were the main environmental factors affecting the spatial structure of the fish community in autumn. The main typifying species, such as Lophius litulon, Paralichthys olivaceus, and Sebastes schlegelii, were mainly distributed around the Changshan Islands. In summary, driven by water temperature, the spatial distribution of typifying species in fish communities during spring was different, and the spatial structure of fish communities showed strong heterogeneity. The spatial pattern of the fish community showed two station groups that are around and off the islands because of the difference in spatial distributions of the main typifying species in autumn.

Abstract:To understand the post-release migration characteristics of Cyprinus pellegrini, an endemic fish in Yunnan, this study conducted a mark-recapture trial to observe the initial post-release migration of hatchery-reared C. pellegrini juveniles in the Qilu Lake. A total of 7000 C. pellegrini juveniles [mean total length (8.4±1.2) cm, mean body weight (7.5±3.5) g] were marked by visible implant elastomer and released in the mark-recapture trial. Recapture was conducted 1 d after release and lasted 3 d. Fyke nets were used for recapture at 10 fixed recapture sites located at the release sites and in nearby waters. A total of 37 released C. pellegrini were recaptured [mean total length (7.1±1.0) cm, mean body weight (4.4±1.8) g], and the total recapture rate was 5.286‰. The markers in the recaptured individuals were clearly visible, and marker retention was 100%. Variation in the number of recaptured fish at each fixed site within 3 d after release showed that the released C. pellegrini quickly moved to shallow water and then to open water. The group adventure of released C. pellegrini on the first day after release was 33.33%, whereas that on the second and third days after release was more than twice of that on the first day. This indicated behavioral characteristics of cautious exploration first and bold adventure later. The daily migration distances of released C. pellegrini at 1, 2, and 3 d after release showed a gradual downward trend, with values of 199.4, 110.6, and 98.8 m/d, respectively. Based on the existing information and results of the present study, suggestions were made to improve the effects of the enhancement and release programs of C. pellegrini.

Abstract:Chlorurus sordidus is a protogynous hermaphroditic coral reef fish that exhibits the phenomenon of spawning agglomeration and is prone to overfishing. C. sordidus is one of the most abundant reef fish in coral reef ecosystems and is widespread on coral reefs throughout the Indo-central Pacific. The herbivorous characteristics of C. sordidus give it the ability to descend and control algae in coral reefs, thereby promoting coral attachment and growth, which has a very important ecological value. Samples were collected from the Yongle Atoll and Meiji Reef by dive fishing in July 2020 and April 2021. Samples were brought back to the laboratory for dissection and analysis after quick freezing. This study determined the biological characteristics of C. sordidus, such as standard length and body weight characteristics, sex ratio, 50% sex reversal standard length, gonadosomatic index, egg size characteristics, and fecundity, with the goal of better protecting and managing this coral reef fish. The results showed that the average standard length and body weight of the Yongle Atoll and Meiji Reef males were significantly larger than females (P＜0.05), but there was no significant difference in the average standard length and body weight of females and the average standard length and body weight of males between the two places (P＞0.05). There was no significant difference in the length-weight relationship between the Yongle Atoll and Meiji Reef, with the relationship being W=9.67×10^–5×L^2.809 and W=7.27×10–⁵×L^2.877, respectively. The male-to-female ratios at the Yongle Atoll and Meiji Reef were significantly different, and the sex ratios were 1.33 1 and 6.33 1, ∶ ∶ respectively, and the male ratio was significantly higher in the Yongle Atoll. The 50% sex reversal standard lengths at the Yongle Atoll and Meiji Reef were 151.60 mm and 174.37 mm, respectively, and the sex reversal standard length of the Meiji Reef was larger than that of the Yongle Atoll, indicating that the female fish in the Meiji Reef did not revert to male until they had grown to a larger size. There was no significant difference in the gonadosomatic index of female gonads at stages III and IV between the two places, which were 1.74 and 2.87 at the Yongle Atoll and 1.86 and 2.77 in the Mischief Reef, respectively. The distribution of egg diameter in both places was continuous, which confirmed that C. sordidus was a typical batch breeding fish. The fecundity and relative fecundity of standard length and body weight of the Meiji Reef were significantly higher than those of the Yongle Atoll. The fecundity and relative fecundity of standard length and body weight at the Meiji Reef were 82941 eggs, 545.59 eggs/mm, and 693.52 eggs/g, respectively, and at the Yongle Atoll were 53540 eggs, 328.20 eggs/mm, and 442.80 eggs/g, respectively. The fecundity of Meiji Reef had no significant relationship with body length and body mass, but there was a significant positive correlation in the Yongle Atoll. The results indicates that fishing pressure had obvious plastic changes in the basic biological characteristics of C. sordidus, especially the sex ratio and fecundity, both reached significant differences. The results of this study provide a basic reference for fish plasticity research and basic data support for the ecological restoration of islands and reefs.

Abstract:The Scomberomorus niphonius is an economically important large-scale pelagic fish in the coastal waters of China. The accurate prediction of the fishing distribution of S. niphonius is of great significance for the assessment and management of fishery resources. The development of satellite remote sensing and artificial intelligence has provided strong technical support and convenience for fishery forecasting research. In this study, a S. niphonius CPUE prediction model based on automatic machine learning was constructed using S. niphonius fishing data, satellite remote sensing sea surface temperature (SST), and sea surface chlorophyll-a concentration (Chl-a) data. Through comparison with the XGBoost, random forest, and generalized additive models (GAM), the coefficient of determination (R² ) of the automatic machine learning model increased by 51%, 107%, and 117%, respectively, and the root mean square error (RMSE) was reduced by 15%, 28%, and 32%, respectively. A fishery abundance index was developed through the CPUE predicted by the model, and the temporal and spatial variation laws of fishery abundance were analyzed. The results showed that the high-abundance area of S. niphonius presented a trend in moving northward and nearshore because of the influence of SST in spring, which is consistent with the feeding and spawning migration route of S. niphonius. The northward shift of the latitudinal center of gravity in the high-abundance area for the S. niphonius fishery was related to the change in the suitable temperature area for feeding and spawning of the S. niphonius under the influence of climate warming. Through the analysis of the climate event index, it was found that the Ni?o 3.4 index was significantly correlated with the area of high abundance of S. niphonius fishery (r=0.58, P＜0.05). Combined with RCP2.6, RCP4.5, RCP6.0, and RCP8.5 for the four scenarios, the distribution changes in the CPUE of S. niphonius by 2100 were predicted. It was determined that with global warming, the high-value production area of CPUE of S. niphonius will continue to move northward, and increase by 0.1 kg/h, 2.2 kg/h, 2.4 kg/h, and 17.3 kg/h, respectively, compared with the predicted average value of CPUE of S. niphonius from 2010 to 2015. The results of this study provide a reference for predicting the fishing conditions of economically important fish species in the coastal waters of China.

Abstract:Olfactory imprinting is a specialized form of unconditioned learning in which olfactory information is acquired and used in specific behavioral contexts later in life. Olfactory imprinting behaviors were particularly evident in reproductive migration, homing, and spawning of some fishes, such as salmon. This brief review outlines the research progress on olfactory imprinting in fishes, including the physiological and molecular mechanisms, and its application in fishery conservation, with the goal of attracting attention to olfactory imprinting in fish habitat protection, stocking enhancement, and aquaculture, and providing guidelines for making decisions regarding fisheries conservation.