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7. Insight into the Population Genetics of the Walleye Pollock Gadus chalcogrammus (Pallas, 1814) in the Northwestern Pacific from Microsatellite Multiplex Assay Study.

Author

Lee, Chung Il, Yoon, Moongeun, Kim, Keun-Yong, Tran, Biet Thanh, Kang, Chang-Keun, Jung, Yun-Hwan, Jung, Hae Kun, Koh, Insong, and Woo, Jiyoung

Abstract

The walleye pollock, Gadus chalcogrammus (Pallas, 1814), is one of the most commercially and ecologically valuable species in the Northwestern Pacific. However, combined pressures of overfishing and environmental changes have led to a substantial decline in its production in Japan and Russia since the 1990s, and a collapse in Korea since the 2000s. The objective of this study was to comprehensively examine its genetic diversity and population structure with an extensive sampling effort of 16 populations across the Northwestern Pacific including South Korea, Japan, and Russia. A multiplex PCR assay composed of seven microsatellite markers revealed a moderate level of observed heterozygosity (Ho = 0.369–0.599), which is lower than that reported in previous studies of this species. All loci were highly polymorphic, with the mean PIC ranging from 0.608 to 0.793. The structure of the 16 populations was characterized by heterozygote deficiency, a modest effective allele number (Ne = 4.551–7.969), low genetic differentiation (FST = 0.000–0.054), a weak population structure, a genetic admixture, and no significant correlation between the genetic and geographic distance. These characteristics are typical of pelagic marine species with large population sizes due to a consistent gene flow among populations when there are no physical boundaries in the open ocean. The seasonal and country-specific genetic structure indicated that G. chalcogrammus populations in the Northwestern Pacific region should be managed as a single management unit. The findings from this study provide critical information for future genetic monitoring, conservation management, and the development of strategies aimed at restoring the populations of this species. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Population genetic analysis of the wild hard-shelled mussel, Mytilus unguiculatus (Valenciennes 1858) in South Korea using a microsatellite multiplex assay

Author

Woo, Jiyoung, primary, Heo, Jung Soo, additional, Kim, Keun-Yong, additional, Kim, Keun-Sik, additional, Hwang, Hyun-Ju, additional, Yoon, Moongeun, additional, An, Hyesuck, additional, Kang, Kook Hee, additional, Park, Jeong Su, additional, Nam, Ki-Woong, additional, Koh, Insong, additional, and Tran, Biet Thanh, additional

Published
2023
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14. Population Genetic Analysis of the Wild Hard-shelled Mussel, Mytilus Unguiculatus(Valenciennes 1858) in South Korea Using a Microsatellite Multiplex Assay

Author

Woo, Jiyoung, Heo, Jung Soo, Kim, Keun-Yong, Kim, Keun-Sik, Hwang, Hyun-Ju, Yoon, Moongeun, An, Hyesuck, Kang, Kook Hee, Park, Jeong Su, Nam, Ki-Woong, Koh, Insong, and Tran, Biet Thanh

Abstract

The Korean or hard-shelled mussel, Mytilus unguiculatus, previously known as Mytilus coruscus, is one of the most economically and ecologically important bivalves in South Korea. However, the population size of this species has drastically reduced owing to overharvesting and habitat shrinkage. Because its genetic information is poorly documented, we contributed, in this study, the genetic diversity and structural analyses of 246 adult samples of M. unguiculatusfrom seven populations along the coastal areas of the mainland and islands of South Korea using a microsatellite multiplex assay. Genetic diversity analyzed from eleven polymorphic microsatellite loci was consistently moderate (0.50–0.57) in all populations. No recent bottleneck was found, indicating that the number of the studied populations did not decrease to an extent that resulted in a reduction of genetic diversity. Additional tests did not reveal any genetic structure across them, possibly resulting from constant gene flow, strong dispersal of planktonic larvae, and genetic admixture between wild populations. These results suggest that M. unguiculatuspopulations along the coastal areas of South Korea should be managed as a single unit. Our study provides crucial information for future genetic monitoring, conservation management, and population restoration plan in preparation for the rapid decline in bivalve resources.

Published
2023
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45. Occurrence of Toxic Alexandrium and Intoxification of Two Mollusk Species by Paralytic Shellfish Poisoning Toxins on the Southeastern Coast of Korea

Author

Lee Jong-Soo, Jang Joon-Ho, Kim Chang-Hoon, Kim Young-Soo, and Kim Keun-Yong

Subjects
biology, Ecology, Toxin, Dinoflagellate, Zoology, Mussel, biology.organism_classification, medicine.disease, medicine.disease_cause, Mytilus, Alexandrium tamarense, medicine, Crassostrea, Paralytic shellfish poisoning, Shellfish
Abstract

We analyzed the paralytic shellfish poisoning (PSP) toxins of the toxic marine dinoflagellate Alexandrium tamarense collected from Dadaepo and Gaduck-do in Busan and from Sujeong-ri in Jinhae Bay, Korea, in April 2003. We also analyzed the PSP toxin of mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) collected around Busan and Jinhae Bay. PSP toxin analyses were conducted by high performance liquid chromatography (HPLC). Fifteen cultured A. tamarense isolates contained 2.78 to 57.47 fmol/cell, with nearly identical toxin profiles: major components C2, GTX4; minor components C1, GTX1, NEO; and trace components GTX2, GTX3, STX. PSP toxin contents were 0 to STXeq/100 g in mussels and 0 to STXeq/100 g in oysters. Mussels at Gijang and Sujeong-ri contained the most PSP toxin contents (), exceeding the quarantine level ( STXeq/100 g). Their dominant toxin components were C2, C1, GTX2, and GTX3; the minor components GTX1, GTX4, GTX5, and NEO were sporadically detected. Phytoplankton contained 0.774 fmol/L seawater and 1.228 fmol/L seawater at Gijang and Sujeong-ri in April. At that time, Alexandrium cells were present in the water column at Gijang at 2,577 cells/mL and at Sujeong-ri at 6,750 cells/mL. Overall, we found the high and similar PSP toxin contents in AZexandrium isolates and mussels, and a correlation between occurrence of toxic Alexandrium cells in the water column and mussel intoxification. High densities of toxic Alexandrium cells in the water column immediately preceded shellfish intoxification at Gijang and Sujeong-ri in April.

Published
2005

46. Spatio-temporal Distribution of Dinoflagellate Resting Cysts at the Saemangeum Area

Author

Kim Chang-Hoon, Park Gi-Hong, Kim Hak Gyoon, and Kim Keun-Yong

Subjects
Dry weight, Range (biology), Alexandrium tamarense, Abundance (ecology), Ecology, Dinoflagellate, Gonyaulax, Biology, biology.organism_classification, Eutrophication, Algal bloom
Abstract

The spatio-temporal distribution of dinoflagellate resting cysts was investigated by palynological processing to understand the harmful algal bloom (HAB) potential in the sediment of the Saemangeun area in 2003. In total, thirty-two dinoflagellate species were identified, and their concentrations were in the range of (dry weight). The concentrations of resting cysts were higher in the spring (26 species, and summer (30 species, than in the autumn (32 species, and winter (24 species, The composition rate of the heterotrophic dinoflagellate species to the total, which is closely related to the eutrophication process, to ranged from 6 to in the study area. The most dominant species was toxic Alexandrium tamarense/catenella followed by Gonyaulax scrippsea and toxic Protoceratium reticulatum Given the high abundance of the toxigenic dinoflagellate species, the Saemangeun area is considered to have the great potential for HABs in the future.

Published
2004

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