Abstract:Pigmentation is a widespread phenomenon in vertebrates that enables vertebrates to adapt to their environment. For example, it can improve concealment and prevent damage from ultraviolet light. Over 250 genes are known to influence the process of melanin synthesis or the formation of pigmentation patterns. Among them, the tyrosinase family genes encode the key enzyme that catalyzes melanogenesis. Dopachrome tautomerase () is a tyrosinase family member and plays a role in catalyzing 5,6-dihydroxyindole (DHI) to 5,6-dihydroxyindole-2- carboxylic acid (DHICA), which is an important substrate for melanin synthesis. However, the effect of on fish pigmentation patterns remains unclear. Common carp is an important aquatic species and there are many varieties of this fish. Oujiang color common carp () is one of these varieties and it has obvious black patches on its skin, which make them a useful material for investigating the function of the gene during pigmentation formation in common carp. In addition, multiple gene copies are common in the Cyprinidae due to additional genome duplication. The effects of copies on Oujaing color carp during melanogenesis remain unclear. The influence of on pigment pattern of black patches in the "WB" pattern of Oujiang color common carp was investigated by cloning genes and measuring their gene expression levels in black patches and white skin tissue using an RT-PCR analysis. CRISPR/Cas9 gene editing technology was used to construct highly mutated Dct mutated carps were observed. This study showed that two ) were detected in Oujiang color common carp. When their DNA sequences in the genome were compared, the results showed that both had CDS sequences that contained 1548 bp nucleotides and encoded 515 amino bases. The alignment results between showed that they had 95.55% nucleotide sequence similarity and 94.95% similarity of amino acid sequences. When they were compared to the Dct amino acid sequence in zebrafish, the results showed that shared similarities of 86.16% and 85.51% in their nucleotide sequences and 88.16% and 86.80% in their amino acid sequences, respectively. The gene expression results revealed that had different expression patterns in the black and white skin areas of the "WB" pattern Oujiang color common carp. expression was significantly higher in the black patch region than in the white skin region ( expression in the white skin areas was significantly higher than in the black patch areas ( mutated phenotype showed that, the black patch regions were smaller on the mutated fishes (mutated efficiency>50%) and there were more non-dendritic like melanocytes appeared. In conclusion, this study showed that may have similar functions during the synthesis of melanin because their amino acid sequences were almost identical. However, the RT-PCR results indicated that played a dominant role in melanogenesis due to its relatively higher expression in black patch tissue. The CRISPR/Cas9 gene editing technology results for enes influenced the pigment pattern of black patches and the morphology of melanocytes in oujiang color common carp. These results offer new insights into the functional effects of genes on pigmentation in common carp.

Abstract:To guide the breeding of (CA), one hybrid F₂[)], two backcross F₂[(BC1-F₂) and (BC2-F₂)] and their parents were analyzed using twenty microsatellite markers. The mean number of alleles (, and BC2-F₂ were 4.50, 4.40, 4.75, 4.85, and 5.10, respectively. The mean values of observed heterozygosity () were 0.7683, 0.5550, 0.7967, 0.8317, and 0.6200, respectively. The mean values of expected heterozygosity () were 0.6671, 0.6308, 0.6995, 0.7240, and 0.6949, respectively, and the average polymorphism information contents (PIC) were 0.6046, 0.5717, 0.6406, 0.6676, and 0.6339, respectively. The mean Hardy-Weinberg indices of MA, MC-F₂, BC1-F₂ displayed a heterozygote excess, whereas the gynogenetic populations (CA and BC2-F₂) showed a heterozygote deficit. The unweighted pair-group method with arithmetic means (UPGMA) showed that the CA and BC2-F₂ populations first grouped together, and then MA and BC2-F₂ grouped together, and then they clustered with MC-F₂. According to the genetic identity analysis, F₂ hybrids and backcross F₂ groups showed maternal effects. Particularly, the microsatellite primers Me.Am._15, Me.Am._1, TTF01, and Mam25 identified five groups. Growth performances of the five groups were analyzed further, and BC1-F₂ groups were found to have the most significant growth advantage. Our results provide important information for the breeding, germplasm resources preservation, and germplasm identification of hybrid F₂ (M. amblephala♀×(M. mblycephala♀×]. To cultivate hybrid strains with fast growth characteristics without adversely affecting the genetic background of the same or similar fish species in natural waters, backcrossing is a feasible method. This paper found that backcrossing could not only improve the superiority of varieties and facilitate correct selection, but also accelerate the stability of the heritability of hybrid offspring, reduce the separation of offspring, and make the heritability of hybrid offspring similar to that of the parent. Therefore, the backcross method lays a genetic foundation for artificial gynogenetic transgenic fish.

Abstract:(Röding, 1798) is an important pearl oyster species used to breed seawater pearls in China because it has advantageous characteristics, such as large size, high pearl secretion and growth rates, strong environmental adaptability, and a high survival rate. Previous research on mainly focused on artificial seedlings, oyster culturing, pearl cultivation, morphology, behavioral science, and histology. There have been no reports on the golden-lip and white-lip breeding lines, and there have been few reports on the growth and development of . Our group found that there was a wide diversity of the colors at the edge of the nacre shell of during the breeding phase and that four breeding lines (two geographic populations and two kinds of lip color) had developed. This study compared the differences in growth and survival rates among the Hainan golden-lip breeding line (GLHH), the Hainan white-lip breeding line (WLHH), the Guangxi golden-lip breeding line (GLGG), and the Guangxi white-lip breeding line (WLGG) of pearl oyster , and investigated the growth patterns of the four breeding lines. The survival rate, the shell length, shell height, shell width, hinge length, and body weight of the four F₃ breeding lines, which had been cultured at Xincun Port, Lingshui Li Autonomous County, Hainan Province, were continuously monitored from January 2018 to the end of December 2018, and one-way ANOVA and growth model fitting were used to analyze the data. The one-way ANOVA results showed significant differences in the growth and survival rates of the four shell color breeding lines ( < 0.05). The growth and survival rate of the Hainan golden lip breeding line was the best, and the growth of the Guangxi white lip breeding line was the worst. The results also indicated that the growth and survival of may related to the environment, age, shell color, and geographical population. The SGompertz growth model is a universal growth model for the five growth traits. The study showed that there were differences in the growth patterns of the four breeding lines, and there were differences among the growth patterns for the five growth traits. The growth inflection points of the shell length and hinge length appeared first, at 7.9 (GLHH)-8.5 (WLHH) and 7.9 (GLHH)-9.1 (WLGG) months old months old, followed by shell height and shell width. The growth inflection point appeared at 11.6 (GLHH)-15.9 (WLGG) months old and 11.8 (GLHH)-14.3 (WLGG) months old, and the body weight growth inflection point appeared at 15.8 (GLHH)−18.7 (WLGG) months old. The results of this study indicated that the Hainan golden-lip breeding line had a high survival rate and excellent growth performance during the early growth stage, and that the Guangxi white-lip breeding line may have the greatest growth potential (the growth limit of growth traits was the largest). The results also provide a reference for the breeding of and the production of high-quality pearls.

Abstract:Reproduction is one of the most important processes in the life history of fish. However, there is little information about the reproductive biology of the fourfinger threadfin, (Show, 1804). In this paper, paraffin tissue sections were used to observe the developmental process of testes via haematoxylin-eosin (HE) staining and transmission electron microscopy (TEM) in order to understand the organizational structure of the testes as well as the histological and ultrastructural changes associated with spermatogenesis during primary sexual maturity in cultured fourfinger threadfin individuals. The results show that the testes are a pair of extended flat zonal organs that are gray in color and fuse at the posterior end into a Y-shape. The organs are located on the dorsal side of the abdominal cavity, attached to the ventral surface of the mesonephros and swim bladder. The developmental process of the testes was divided into six stages defined by histological characteristics. The testes develop to stage I (spermatogonia proliferates), followed by stage II (spermatocyte growth), stage III (spermatocytes mature), and stage IV (sperms begin to appear) at about three months of age, four months of age, five to seven months of age, and seven to nine months of age, respectively. At a minimum of 10 months of age, the testes develop to stage V (complete maturation of sperm) and reach the first stage of sexual maturity. The post-reproductive testes in stage VI (degradation and absorption) were observable after the breeding season. Spermatogenesis went through six phases, namely primary spermatogonia, secondary spermatogonia, primary spermatocyte, secondary spermatocyte, spermatocyte, and sperm in succession. The diameter of cells and nuclei decreased step by step, and the ratio of nucleus to cytoplasm changed regularly. During spermatogenesis, chromosomes in the nucleus were gradually condensed, electron density was increased, and mitochondria were enlarged and aggregated with inner cristae structure gradually enriching. Sperm was composed of a head, middle, and tail. The axial filament of the flagella followed a typical "9+2" structure. This study elaborated on the organizational structural characteristics of the testes and the histological and ultrastructural changes during testes development and the spermatogenesis process of first sexual maturity stage of cultured fourfinger threadfin. This information enriches our collective knowledge on the species' reproductive biology and provides a theoretical reference for understanding reproduction laws and improving artificial breeding technologies.

Abstract:As one of the most important marine ornamental fish, is a protogynous hermaphrodite with a natural sexual reversion. Under appropriate social conditions, a female fish can transform into a male fish spontaneously. It is an important prerequisite for artificial breeding to understand the process of its gonadal development and sexual reversion. In this paper, sexual reversion was induced by artificial pairing, and the process of sexual reversion and gonadal development were studied using morphological and histological methods. The results showed that the gonads of could be divided into three types:pure female with ovaries, pure male with testes, and ♀/♂ bisexual. The gonads differentiate into those of females with pure ovaries at first; then sexual reversion occurs in stage II ovaries. The ovaries of a large female fish stop developing and atrophy gradually occurs in stage II after pairing induction for 1-2 weeks by one big and one small pair. At the same time, male germ cells are gradually differentiated from the ovarian wall and the oviposition plate; and female and male germ cells coexist in the gonad, forming a bisexual gonad of the hermaphrodite stage. After three weeks of pairing induction, the bisexual gonad differentiates into early testes entirely, indicating that the female has completed sexual reversion and has become a functional male. After four weeks of pairing induction, the testes of sexually-reverted males and the ovaries of small females mature and start spawning and spermiation. The relationship between total length, body mass, and sexual reversion was also analyzed, and the process, characteristics, and possible induction mechanisms of sexual reversion have been discussed. The results will provide theoretical guidance for artificial breeding and sex control technologies in , and lay the necessary groundwork for further research on the mechanisms of gonadal development and sexual reversion in , and enrich our understanding of hermaphroditic coral fishes.

Abstract:The in-pond raceway system (IPRS) combines the sustainable development of environmental protection and high yields. Compared with traditional pond culture, the IPRS can improve the survival rate, muscle nutrition, liver biological function, and antioxidant capacity of largemouth bass (). Stocking density is an important environmental factor in the in-pond raceway system, but the high densitie can cause stress responses in fish, which have negative impacts on growth, behavior, and physiology. Therefore, a suitable stocking density for largemouth bass () in a recirculating aquaculture system needs to be identified. A 120-day feeding experiment was performed to study the effects of stocking densities on the antioxidant state, digestive enzymes, tissue structure, and the gene expressions of in largemouth bass (average initial body weight 4.50±0.23 g) reared in in-pond raceway culture systems. The fish were divided into three density groups (SD1, 0.2 kg/m³; SD2, 0.4 kg/m³; and SD3, 0.6 kg/m³). Each density was tested in triplicate. The relative indicators in the liver and intestine were measured, and the histological structures of the liver and intestine were observed at days 30, 60, 90, and 120. The results showed that the final densities at the end of the experiment were 5.64 kg/m³ (SD1), 8.79 kg/m³ (SD2), and 11.21 kg/m³ (SD3). There were no significant difference in liver SOD and CAT activity among the treatments on days 30, 60, and 90 (>0.05). However, the fish reared in the SD1 group had significantly higher values than those reared in the SD3 group on day 120 (>0.05). There were no significant differences in the MDA contents of the livers before 60 d (>0.05), but fish reared in the SD3 group had significantly higher values than those reared in the SD1 group on days 90 and 120 (>0.05). The amylase and lipase activities in the intestines of the fish reared at the three groups were not significantly different (HSP70 and P>0.05).The expression of in the livers of the fish from SD3 was significantly higher than those from the SD1 and SD2 groups at 90 d and 120 d ( mRNA in the livers of the fish in SD1 was significantly higher than that in SD3 at 90-120 d (>0.05). The tissue section observations showed that the liver and intestinal tissues of the three density groups were normal and not seriously damaged, whereas the stress caused by the high stocking density led to a slight increase in vacuoles among the liver tissues and a decrease in the size and number of intestinal goblet cells at the end of the experiment. The results showed that the stress caused by the high stocking density inhibited the antioxidant capacity of largemouth bass and affected the expression of the genes in the liver. It also had a slight effect on liver and intestinal structure. In conclusion, the stocking density affected the physiological status of largemouth bass and inhibited the antioxidant and immune functions of the fish. Moreover, the high-density stress caused slight damage to the liver and intestinal tissues under the conditions of this experiment. In summary, the largemouth bass reared in the 0.2 kg/m³ density group had the best physiological status. Overall, the results suggest that largemouth bass can be reared at stocking densities of 0.2−0.4 kg/m³ in an IPRS.

Abstract:This experiment was conducted to investigate the effects of different lipid sources and potassium iodate in diets on the growth, survival rate, liver and gut histomorphology, lipid metabolism gene expression, and microRNA expression of juvenile Chinese soft-shelled turtle (). Four diets were prepared on the basis of fish oil (FO), fish oil + potassium iodate (FO + PI), tea seed oil (TO), and linseed oil (LO). All diets contained 10% oil and potassium iodate with the concentration of 75 mg/kg. The diets were fed to the turtles (mean body weight:5.06±0.05 g) for 66 days. The results showed that the survival rate of juvenile turtles in FO + PI and LO groups was significantly lower than that in the FO group, and hepatosomatic index (HSI) of the FO + PI group and TO group was also significantly reduced. There were no significant differences in plasma glucose, total cholesterol, and triglyceride levels among the groups. Turtles fed the FO + PI diet significantly downregulated the gene expression of -23b, -499. The TO diet significantly downregulated the expression of and upregulated the expression of microRNA-23b. There were fewer lipid vacuoles in the liver cells from the FO + PI group and the TO group. In addition, the TO diet significantly altered the morphology of mucosal folds in the intestines of the turtles. It was concluded that different lipid sources and potassium iodate in the juvenile turtle diets had no significant effect on their growth. However, linseed oil and potassium iodate affected their survival rate, while tea seed oil and potassium iodate influenced lipid metabolism in juvenile Chinese soft-shelled turtles.

Abstract:The present study aimed to determine the effects of dietary nano-selenium (0.0 mg/kg, 0.2 mg/kg, 0.4 mg/kg, 0.8 mg/kg) added to feed for eight weeks on growth, muscle composition, serum biochemical and antioxidant indices of individuals with similar body weight (98.75±5.74 g) were randomly assigned to four groups with three replicates per group and 30 fish per replicate. Fish were starved for 24 h before sampling, and body weight, length, and width were prepared for measurement of growth indicators. The head, kidneys, spleen, liver, mesonephros, and intestines were prepared for the immune organ index. Muscle was prepared for body composition analysis. Blood samples were collected from the caudal vein and were used directly to assay indicators in the serum of . The results were as follows. Compared with the control group (basal diet), specific growth rate (SGR) and intestinal weight index (IWI) were increased, and feed conversion ratio (FCR) was decreased, with the increasing of supplement of nano-selenium (<0.05). Weight gain rate (WGR) also increased when diets were supplemented with 0.2 mg/kg nano-selenium. The intestinal ratio (IR) of was significantly increased when 0.4 mg/kg and 0.8 mg/kg nano-selenium was added (<0.05). Additionally, the crude protein content of muscles was significantly increased when 0.4 mg/kg and 0.8 mg/kg nano-selenium was added (<0.05). Compared with the control group, the serum globulin (GLOB), triglyceride (TG), and cholesterol (TC) content of the fish were significantly increased when diets were supplemented with different doses of nano-selenium (<0.05). At the same time, the serum superoxide dismutase (SOD) activity of fish was significantly increased, and the serum malondialdehyde (MDA) and glucose (Glu) content of fish were significantly decreased (<0.05) in the Se supplemental group. The serum glutathione peroxidase (GSH-Px) activity of was significantly increased when 0.4 mg/kg and 0.8 mg/kg nano-selenium was added to the diet. Serum nitric oxide synthase (iNOS) activity and muscle selenium content was significantly increased when 0.8 mg/kg nano-selenium was added. Taken together, the results showed that nano-selenium had certain effects on the growth and development of the fish, and that it improved muscle quality and serum antioxidant performance. The optimal levels of dietary nano-selenium supplement in were estimated to be 0.52 mg/kg using quadratic regression analysis based on specific growth rate. Through comprehensive consideration of growth performance, antioxidant status, and lipid metabolism, the supplement level of 0.5 mg/kg nano-selenium is recommended in diets of . This study provides a new theoretical basis for the development of nutritional feed for .

Abstract:The effects of salinity on osmoregulation, gill Na⁺/K⁺-ATPase activity, gene expression, and oxygen consumption rate of juvenile hybrid grouper () were studied. In experiment 1, juvenile hybrid groupers with average weight of (162.5±12.1) g were exposed to different salinities (6, 12, 18, 24, 30) for 10 days. Serum osmolality and ion (Na⁺, Cl^‒, and K⁺) concentrations were determined. The results showed that serum osmolality and Na⁺, Cl^‒, and K⁺ concentrations increased with increasing salinity. Serum osmolality and Na⁺ and Cl^‒ from salinity group 6 were significantly lower than those of the control group (]:[Cl^‒] ratio between the groups (>0.05). The isosmotic point was calculated as 365.95 mOsm/kg, corresponding to the osmolality of the ambient water at a salinity of 12.75. In experiment 2, juvenile hybrid groupers with average weight of (26.4±2.7) g were reared at different salinities (6, 12, 18, 24, 30) for 30 d, and the activity and expression of gill Na⁺/K⁺-ATPase were measured at 0 h, 3 h, 24 h, and 72 h, as well as the oxygen consumption rate at 30 d. The results showed that the activity change curve of gill Na⁺/K⁺-ATPase was U-shaped as salinity increased, and at 3 h, the activity was significantly the lowest at salinity 18 and 24 (<0.05). After 24 h and 72 h, the activity of salinity 12 was significantly lower than all other groups ( gene fluctuated greatly, beginning with a decrease and then increasing after 72 h, which was consistent with the enzyme activity. Gene expression in salinity 12 group was significantly lower than that in the other groups (<0.05). With increasing salinity, the oxygen consumption rate initially decreased, followed by an increase, and then again a decrease. Oxygen consumption was highest in salinity group 6 and was significantly higher than that in salinity groups 12, 18, and 30 (<0.05). Our findings indicate that the juvenile hybrid grouper can adapt to 6-30 salinity changes well. Near the isosmotic point, Na⁺/K⁺-ATPase activity, oxygen consumption rate, and the relative expression of gill were lower, suggesting that growth was more favorable near this point. However, the activity of Na⁺/K⁺-ATPase was not completely consistent with the oxygen consumption rate in the experiment, indicating the oxygen consumption rate may be related to its life history stage except for regulation of ion permeability.

Abstract:Growth and mortality parameters of fishes constitute the basis of fishery assessments and management. In this study, growth parameters from three time periods ("early", "middle", and "recent") were studied based on sand lance samples collected from 2002 to 2018 in the Yellow Sea. Early period refers to early 2000s, middle period refers to late 2000s, and recent period refers to late 2010s. The results showed that the biological characteristics of sand lance had changed significantly throughout this period. The dominant body length decreased from 130−150 mm in the early period to 80−110 mm in the recent period. Body weight composition changed from a uniform distribution in the early and middle periods to those of small individuals in the recent period. The dominant age group changed from 2-year-old individuals in the early period to individuals born in the current year in the recent period. The of von Bertalanffy growth equations for the early period, middle period, and recent period were 194.2 mm, 179.6 mm, and 161.7 mm, respectively, and the growth rates were 0.31, 0.42, and 0.47 in the early, middle, and recent periods, respectively. Significant differences were observed in the von Bertalanffy growth models (<0.05) between the middle period and recent period. Compared with the previous two periods, the of the recent period was significantly decreased, and the growth rate increased rapidly. The condition factors of sand lance in the spring, summer, and winter of the recent period were decreased compared to the same seasons in the early period. The total mortality rates () of the three periods were 1.14, 2.00, and 0.74, respectively, the fishing development rates () of the three periods were 0.69, 0.78, and 0.32, respectively, and the natural mortality rates () of the three periods were 0.35, 0.44, and 0.50, respectively. Sand lance have been over-exploited since its large-scale development and fish tended to be smaller and younger in recent sampling efforts. Such changes may be caused by overfishing.

Abstract:To clarify the sedimentation characteristics of aquaculture-derived organic matter (AOM) from a large yellow croaker () cage farm in Sansha Bay, AOM samples in a sampling gradient (0-200 m away from the culture cage) were collected with sedimentation traps under two typical feeding conditions (commercial feed and raw fish). These samples were used to analyze sedimentation rate, particle organic matter (POM:particulate organic matter; POC:particulate organic carbon; PN:particulate nitrogen; TP:total phosphorus) fluxes, and their spatial expansion in this study. The sedimentation rate of AOM was (563.66±119.18) g/(m²·d) when commercial pellets were used as feed, which was significantly higher than that when raw fish was used. Particulate organic matter (POM), POC, PN, and TP fluxes were much higher when using commercial feed than raw fish, at (27.25±2.43) g/(m²·d), (6.03±0.58) g/(m²·d), (0.66±0.06) g/(m²·d), and (0.39±0.04) g/(m²·d) in the former experimental condition, and at (13.04±1.62) g/(m²·d), (3.57±0.45) g/(m²·d), (0.51±0.06) g/(m²·d), and (0.22± 0.04) g/(m²·d) in the latter situation, respectively. Particle organic matter fluxes and AOM sedimentation rates showed decreasing tendencies from 0-100 m away from the fish cage, with a particularly strong decline in the raw fish treatment. The percentage of particle organic matter in AOM also exhibited spatial variability, declining in the region from the fish cages to 50 m downstream. In summary, the environmental effects of a cage farm in Sansha Bay were much remarked when commercial pellets were used as feed. Environmental impacts derived from using both commercial pellets and raw fish were restricted to an area 50-100 m away from fish cages. The occurrence of conspicuous environmental impacts due to using commercial feeds was associated with a greater AOM sedimentation rate, and thus, studies on restricted feeding and on the efficiency of fish feed are essential to alleviate the negative impacts of aquaculture in the area.

Abstract:Antarctic krill () is one of the largest single species of biological resource on the planet. It lives mostly in the waters south of 50° S in the Southern Ocean, and is distributed around the Antarctic. Studying the behavior patterns of Antarctic krill clusters is of great significance for understanding their distribution characteristics, the formation mechanism of Antarctic krill fishing grounds, and resource utilization. As Antarctic krill occupies a key position in Antarctica and the Southern Ocean ecosystem, the regionality of its living conditions, special rhythms, and vulnerability, have made it difficult to study the rules governing its aggregation. Antarctic krill uses the phenomenon of diel vertical migration and aggregation. In this study, diel aggregation and Antarctic krill biology were studied in the waters of the South Orkney Islands. The results show that the horizontal band which refers to the pattern of aggregation has a dominant distribution in each time period, but that the proportion of horizontal band in each time period is significantly different. From dawn to dusk, the proportion of the horizontal band decreased first, and then increased, reaching the lowest value in the daytime period (65%). From dusk to morning twilight, the proportion of the horizontal band was high and stable. Spherical distribution maintains a relatively stable time interval, and scattered distribution is a continuous feature from sunrise to the daytime. The central depth of the Antarctic krill aggregation varies greatly during different time periods; morning twilight and evening twilight are the dividing points of the average aggregation center depth. The central depth of Antarctic krill is also different in terms of aggregation. The average central depth of the spherical distribution is the largest, followed by scattered distribution. Alternately, the average central depth of the horizontal band is the least. The temperature of aggregation fluctuates in different time periods, ranging from -1.6℃ to 1.3℃. The minimum value appears during the evening twilight period, and the maximum value appears at night. The temperature of aggregation and the central depth of the Antarctic krill show a significant negative correlation. The body length of Antarctic krill is significantly different in different time periods (<0.001), and the dominant body length in different time periods is significantly different, with the dominant body length between daytime and afternoon being significantly higher than in other time periods.

Abstract:Net shape is an important indicator of the operative performance of tuna purse seine, and can be affected by many factors, such as twine material, leadline weight, fishing operation, and currents. In order to understand the effect of shooting pattern and current speed on the shape of tuna purse seine, a model net was manufactured from the prototype net used by Chinese tuna purse seiners, based on the Tauti law. The experiment was carried out in the circulating tank at Nichimo Co., Ltd. of the Shimonoseki Research Institute. The effects of three shooting patterns (front set, cross set, and back set) and three current speeds (0 cm/s, 5 cm/s, and 8 cm/s) on the shape of the model net (the sinking depth of the leadline, the profile of the net, the opening surrounding the areas of the floatline and leadline, and the shape of the floatline and leadline) were investigated in this study. The results showed that:(1) when the current speed was 0 cm/s, the sinking depth of the leadline, and the opening area surrounded by the floatline and leadline reached the maximum of 1.21 m, 8.44 m², and 9.89 m², while the net maintained a better shape; (2) when the current speed was 5 cm/s at the front set, the shapes of floatline and leadline were better compared with the other experimental conditions; (3) at the front set and back set, the sinking depth of the leadline decreased with increasing current speed (1.21 m for the front set and 1.21 m for the back set at 0 cm/s > 1.17 m for the front set and 1.16 m for the back set at 5 cm/s > 1.13 m for the front set and 1.10 m for the back set at 8 cm/s), and the sinking depth of the leadline significantly differed with current speed (<0.05); (4) at the cross set, there was no significant difference in the sinking depth of the leadline for different current speeds (>0.05); (5) for each shooting pattern, current speed did not significantly affect the initial opening areas surrounding the floatline and leadline (>0.05); (6) the opening areas surrounding the floatline and leadline had a linear relationship with the square of time (<0.05). Based on the above results, we recommend cross set in practice, because it ensures a better shape of the net and a greater sinking depth of the leadline.