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open access
메뉴This study investigated the characteristics of sediment immersion activity in order to utilize them as a basis for suitable site selection when releasing cockle, Fulvia mutica spat. The cockle, F. mutica spat were spawned from natural broodstock in April, and the cockle spat (shell length 17.96 ± 4.78 mm) were reared in a 2 ton FRP square tank (300 × 100 × 70 cm) for 185 days in a flow-through system. To investigate the sediment immersion activity characteristics, 30 were placed in each sediment grain size of fine sand (0.12 ± 0.03 mm), medium sand (0.93 ± 0.24 mm) and coarse sand (2.69 ± 0.67 mm), and the immersion rate and immersion time of each individual spat were investigated. As a result, the in rate of each 10-20 mm cockle spat was more than 90% within 60 minutes except for the coarse sand, and the immersion time was more than twice as long.
This study investigated the characteristics of sediment immersion activity in order to utilize them as a basis for suitable site selection when releasing cockle, Fulvia mutica spat. The cockle, F. mutica spat were spawned from natural broodstock in April, and the cockle spat (shell length 17.96 ± 4.78 mm) were reared in a 2 ton FRP square tank (300 × 100 × 70 cm) for 185 days in a flow-through system. To investigate the sediment immersion activity characteristics, 30 were placed in each sediment grain size of fine sand (0.12 ± 0.03 mm), medium sand (0.93 ± 0.24 mm) and coarse sand (2.69 ± 0.67 mm), and the immersion rate and immersion time of each individual spat were investigated. As a result, the in rate of each 10-20 mm cockle spat was more than 90% within 60 minutes except for the coarse sand, and the immersion time was more than twice as long.
This study aims to explore measures to continuously improve shellfish productivity in the West Sea coastal region (Incheon metropolitan city, Gyeonggi-do, Chungcheongnam-do, and Jeollabuk-do), which has a high proportion of aquaculture among domestic shellfish production areas. To analyze changes in shellfish production in the West Sea coastal region over 52 years, we compared changes in tidal flat area and production by fishery and species from 1970 to 2022 using data from the KOrean Statistical Information Service (KOSIS, 2023). As a result of the analysis, West Sea region over the past 10 years (2013-2022) was a total of 50,092 tons (28,997 tons of offshore fisheries, 21,095 tons of shallow-sea aquacultures), aquaculture ratio accounted for 40.4%. Shellfish production by fishery in the West Sea area for 52 years (1970-2022) includes 23 species of offshore fisheries, and the main species targeted for fishing include sunray surf clams, surf clam, oysters, and manila clam. There are 16 species of shallow-sea aquacultures, and the main species targeted for aquaculture include manila clam, oysters, surf clam, and venus clams. Changes in tidal flat area due to reclamation projects had a significant impact on the production of burrowing shellfish. Over the past 31 years (1987-2018), the change in the area of the West Coast tidal flat decreased 590 km2 from 1,935.4 km2 to 1,345.4 km2, showing a decrease rate of 30.5%, a high decrease compares to other regions across the country. In conclusion, it is believed that the way to continuously improve the productivity of shellfish is to protect natural seed and shell growth areas, selecting habitat suitability and suitable sites for each species, managing seed release, and expanding shellfish seed production and intermediate cultivation infrastructure.
This study aims to explore measures to continuously improve shellfish productivity in the West Sea coastal region (Incheon metropolitan city, Gyeonggi-do, Chungcheongnam-do, and Jeollabuk-do), which has a high proportion of aquaculture among domestic shellfish production areas. To analyze changes in shellfish production in the West Sea coastal region over 52 years, we compared changes in tidal flat area and production by fishery and species from 1970 to 2022 using data from the KOrean Statistical Information Service (KOSIS, 2023). As a result of the analysis, West Sea region over the past 10 years (2013-2022) was a total of 50,092 tons (28,997 tons of offshore fisheries, 21,095 tons of shallow-sea aquacultures), aquaculture ratio accounted for 40.4%. Shellfish production by fishery in the West Sea area for 52 years (1970-2022) includes 23 species of offshore fisheries, and the main species targeted for fishing include sunray surf clams, surf clam, oysters, and manila clam. There are 16 species of shallow-sea aquacultures, and the main species targeted for aquaculture include manila clam, oysters, surf clam, and venus clams. Changes in tidal flat area due to reclamation projects had a significant impact on the production of burrowing shellfish. Over the past 31 years (1987-2018), the change in the area of the West Coast tidal flat decreased 590 km2 from 1,935.4 km2 to 1,345.4 km2, showing a decrease rate of 30.5%, a high decrease compares to other regions across the country. In conclusion, it is believed that the way to continuously improve the productivity of shellfish is to protect natural seed and shell growth areas, selecting habitat suitability and suitable sites for each species, managing seed release, and expanding shellfish seed production and intermediate cultivation infrastructure.
To understand the characteristics of the salinity distribution, salinity data were observed by depth at 18 stations in the downstream of the Seomjin river. In order to analyze the characteristics of long-term variations of the salinity, observed data from 2003 to 2017 were collected and compared. According to the results of the analysis, the distribution of the isohaline due to the difference of the tidal height moved to the upstream of the Seomjin river at high tide, and the travel distance depend on the flow rate. In the case of normal flow rate(15-30 cms), the movement of the isohaline due to the difference of the tidal height was about 5 to 7 km, and when the low level flow rate (< 15 cms), the isohaline is located upstream compared to the normal flow rate and the isohaline moves 1 to 2 km by tides. Changes of the salinity distribution caused by tides were affected up to 25 km from the entrance of the Seomjin river. It was estimated that the flow rate of more than 40 cms was required to maintain the salinity of 5-15 psu in the habitat of the Corbicula japonica.
To understand the characteristics of the salinity distribution, salinity data were observed by depth at 18 stations in the downstream of the Seomjin river. In order to analyze the characteristics of long-term variations of the salinity, observed data from 2003 to 2017 were collected and compared. According to the results of the analysis, the distribution of the isohaline due to the difference of the tidal height moved to the upstream of the Seomjin river at high tide, and the travel distance depend on the flow rate. In the case of normal flow rate(15-30 cms), the movement of the isohaline due to the difference of the tidal height was about 5 to 7 km, and when the low level flow rate (< 15 cms), the isohaline is located upstream compared to the normal flow rate and the isohaline moves 1 to 2 km by tides. Changes of the salinity distribution caused by tides were affected up to 25 km from the entrance of the Seomjin river. It was estimated that the flow rate of more than 40 cms was required to maintain the salinity of 5-15 psu in the habitat of the Corbicula japonica.
With fast growth and a higher meat quality, a triploid cultchless single shell oyster has become a one of major source of the world oyster production. In South Korea where most of the Pacific oyster productions are based on long-line suspended diploid oysters, there are growing demands on a high-quality and more profitable oysters. When compared to the suspended diploid oysters on the south coast, individuals reared in tidal flats on the west coast shows greater performance in terms of a shell thickness, strength, and taste. Hence, we tested for the translocation of a triploid cultchless single shell oyster from Tongyeong on south coast to Boryeong on the west coast in order to determine the optimal timing and location of transplantation. As a result, the oysters translocated in April showed the lowest cumulative mortality when compared to the oysters translocated in June and September, indicating that the spring is the optimal timing of location due possibly to the highest primary productivity in the intertidal zone throughout the year. In addition, the oysters reared in the lower intertidal zone was more favorable than in the upper intertidal zone in terms of tissue dry weight and condition index. Considering that the oysters tissue weight in the lower intertidal zone peaked in August and decreased from September due to the high summer temperature, it is suggested that translocation should be carried out in April and harvested during August to maximize the yield.
With fast growth and a higher meat quality, a triploid cultchless single shell oyster has become a one of major source of the world oyster production. In South Korea where most of the Pacific oyster productions are based on long-line suspended diploid oysters, there are growing demands on a high-quality and more profitable oysters. When compared to the suspended diploid oysters on the south coast, individuals reared in tidal flats on the west coast shows greater performance in terms of a shell thickness, strength, and taste. Hence, we tested for the translocation of a triploid cultchless single shell oyster from Tongyeong on south coast to Boryeong on the west coast in order to determine the optimal timing and location of transplantation. As a result, the oysters translocated in April showed the lowest cumulative mortality when compared to the oysters translocated in June and September, indicating that the spring is the optimal timing of location due possibly to the highest primary productivity in the intertidal zone throughout the year. In addition, the oysters reared in the lower intertidal zone was more favorable than in the upper intertidal zone in terms of tissue dry weight and condition index. Considering that the oysters tissue weight in the lower intertidal zone peaked in August and decreased from September due to the high summer temperature, it is suggested that translocation should be carried out in April and harvested during August to maximize the yield.
Korea is a significant contributor to the global catch and trade of Cephalopods. However, most of the imported cephalopods do not have accurate Korean names, leading to confusion and deception among consumers. To protect consumers and prevent such confusion, a scientific Korean naming system was established through a conducted study. The study resulted in the creation of a taxonomic list that includes 412 species of cephalopods eligible for import, each with a Korean name. The Octopodidae family had the highest number of species with 71, followed by the Sepiidae family with 65 species, the Loliginidae family with 47 species, and the Ommastrephidae family with 22 species.
Korea is a significant contributor to the global catch and trade of Cephalopods. However, most of the imported cephalopods do not have accurate Korean names, leading to confusion and deception among consumers. To protect consumers and prevent such confusion, a scientific Korean naming system was established through a conducted study. The study resulted in the creation of a taxonomic list that includes 412 species of cephalopods eligible for import, each with a Korean name. The Octopodidae family had the highest number of species with 71, followed by the Sepiidae family with 65 species, the Loliginidae family with 47 species, and the Ommastrephidae family with 22 species.
This study aimed to develop a genetic analysis method to identify the origin of cockles (Tegilarca granosa). Initially, analysis of the mitochondrial COI gene revealed genetic variations among Korean, Chinese, and Japanese cockles. While distinguishing between Chinese and Japanese cockles was challenging, a specific haplotype (H1) found only in Korean cockles allowed researchers to infer their origin. Next, we analyzed the genetic characteristics of cockle populations using 19 microsatellite markers. This analysis validated the accuracy of assigning a cockle's origin and assessed the reliability of this method. The analysis revealed that three genetic loci (Teg02, Teg08, TMP18) displayed differing numbers of alternative alleles expressed between domestic populations and Chinese and Japanese populations, indicating genetic differentiation due to geographic separation. Using 16 microsatellite markers, the accuracy and reliability of origin determination achieved 89.6% and 86.6%, respectively. This shows there's enough information to distinguish between Korean, Chinese, and Japanese cockles. The results of this study demonstrate the usefulness of genetic analysis methods in determining the origin of cockles. This method is expected to contribute significantly to ensuring the safety and quality management of cockle distribution in the future. Additionally, there is a need for continued research to improve the accuracy and ability to differentiate origins through further development of microsatellite marker-based methods.
This study aimed to develop a genetic analysis method to identify the origin of cockles (Tegilarca granosa). Initially, analysis of the mitochondrial COI gene revealed genetic variations among Korean, Chinese, and Japanese cockles. While distinguishing between Chinese and Japanese cockles was challenging, a specific haplotype (H1) found only in Korean cockles allowed researchers to infer their origin. Next, we analyzed the genetic characteristics of cockle populations using 19 microsatellite markers. This analysis validated the accuracy of assigning a cockle's origin and assessed the reliability of this method. The analysis revealed that three genetic loci (Teg02, Teg08, TMP18) displayed differing numbers of alternative alleles expressed between domestic populations and Chinese and Japanese populations, indicating genetic differentiation due to geographic separation. Using 16 microsatellite markers, the accuracy and reliability of origin determination achieved 89.6% and 86.6%, respectively. This shows there's enough information to distinguish between Korean, Chinese, and Japanese cockles. The results of this study demonstrate the usefulness of genetic analysis methods in determining the origin of cockles. This method is expected to contribute significantly to ensuring the safety and quality management of cockle distribution in the future. Additionally, there is a need for continued research to improve the accuracy and ability to differentiate origins through further development of microsatellite marker-based methods.
