ISSN : 1225-3480
Three marine gastropod species were collected in 2000 and 2019 years from Korean waters (Daejin, Gangwon-do; Dongmak, Incheon City; Seogwipo harbour, Jeju-do). They were identified as Sagamilepeta sagamiensis (Kuroda & Habe, 1971), Fluviocingula nipponica Kuroda and Habe, 1954 and Distorsio reticularis (Linnaeus, 1758) that come out into the unrecorded species in Korea. In this study, we provide descriptions and pictures of the shell morphology of three species as a new record in the Korean sea.
A single specimen belonging to the family Bursidae was collected during a scuba diving survey in Jeju Island in Korea and was identified as the red-mouth frog shell, Tutufa bufo (Roding, 1798). To date, two bursid species, Bufonaria rana (Linnaeus, 1758) and Bursa bufonia (Gmelin, 1791), have been recorded in Korean waters. In this study, we describe Tutufa bufo, including coloration and radula shape based on a newly collected specimen. In addition, the partial gene sequence of mitochondrial cytochrome c oxidase subunit I (mt COI) is determined for molecular analysis.
A single individual marine gastropod species was collected by harbor survey (Seoqwipo port) and was identified as Antillophos nigroliratus (Habe, 1961). To date, 24 species from five genera and three subfamilies in the family Nassariidae have been recorded in Korea. In this study, we provide descriptions and photographs of A. nigroliratus as a new record in Korean waters.
We examined the regional catch characteristics of leisure fishing on Amphioctopus fangsiao in Jellanam-do Province from January 2017 to October 2018. The daily catch data of A. fangsiao was examined by korea fisheries cooperative in 8 regions and by leisure fishing in 11 regions of Jeollanam-do province. The population of A. fangsiao by leisure fishing in Jeollanam-do province was estimated to 49,397. In Yeosu, there were estimated to 40,490 population and it accounted for 81.9% of total population of leisure fishing on A. fangsiao. The total catch of A. fangsiao was the highest in Goheung, and the catch per unit effort (CPUE, kg/vessels) was highest in Mokpo in 2017 and Jangheung in 2018. The CPUE of A. fangsiao by leisure fishing was the highest in Yeosu and the lowest in Muan. The CPUE of catch data of korea fisheries cooperative and leisure fishing of A. fangsiao, which accounted for the catch ratio of leisure fishing ranging from 0.4 to 406 times higher than catch data of korea fisheries cooperative. Therefore, the exact catch data of A. fangsiao needed for efficient resource management and protection and also need to catch data of korea fisheries cooperative and by leisure fishing. It is necessary to exact methods to find an uncounted catch data by leisure fishing on A. fangsiao.
In this study, we conducted a study on catch characteristics such as the total amount of catch and the catch per unit effort in the coastal area of Jeollanam-do Province for the sake of effective fisheries management of Octopus minor. The Gamak·Yeosa Bay were the only area characterized by high number of individuals, amount of catch and catch per unit effort through 2017 to 2018. On the other hand, Sinan coastal area was the lowest. Monthly number of individuals was high in February 2017 and January 2018. Monthly amount of catch per unit effort was high in January-March 2017 and January-February 2018. Monthly amount of money per unit effort differed from coastal areas to bays. The ratio of local immature of Octopus minor was the highest at Gangjin with 80.7% and the lowest at Jangheung with 50.9%. The ratio of monthly immature of Octopus minor was the highest at 91.3% in August and the lowest at 41% in July.
Our previous findings revealing that Karenia mikimotoi toxicity might not be potent enough to cause abalone Haliotis discus hannai mass mortality necessitated further verification in more scientific ways. Focal points were on exposure extension and use of replication and harmless flagellate reference for valid comparison. The exposure lasted 2 days with a daily solution renewal. Harmless Tetraselmis suecica were additionally tested as a reference. All the tests were duplicated. The key methods otherwise mentioned followed our previous study (see Korean J. Malacol. 35(2): 87-92). Results were clear-cut, harmless or harmful. K. mikimotoi at 2 x 104 cells ml-1 together with the two references, seawater and T. suecica at 10 x 104 cells ml-1, were harmless all the way throughout the exposure, while a reference, Cochlodinium polykrikoides at 5 x 103 cells ml-1, was markedly harmful. C. polykrikoides damage was statistically significant from 12 hours after exposure (P < 0.05). These data are highly suggestive of lower damage potential of K. mikimotoi to the abalone even though something uncertain and thus needing verification are still existing.
Ark shell (Scapharca broughtonii) is cultured in southern coast of Korea and is a commercially important shell in aquaculture. However its productivity has decreased rapidly in the last decade due to mass mortality. Various microbial investigations were performed to identify the caused bacterial species for economic losses. Using cumulative mortality analysis, 16S rDNA sequence analysis, and API 20 kit assay, Vibrio parahaemolyticus-related species (8M 4-1) was identified as an etiologic bacterium. The LD50 value of the isolated bacterium to ark shell was lower than 106 CFU/mL. After infection, histological diagnosis from hepatopancreatic tissue also provided evidence for pathogenicity. To monitor this ark shell pathogenic bacterium, we designed the PCR detection method with the Vibrio species groEL gene. We also tested various virulence gene-targeted detection methods, but amplified products were not suitable for V. parahaemolyticus recognition. In this study, we identified V. parahaemolyticusrelated species as a causative organism of mass mortality, and demonstrated that PCR detection assay could successfully detect V. parahaemolyticus strains from infected tissues with high sensitivity. Using these results, we identified V. parahaemolyticus-related 8M 4-1 species as the causative agent of ark shell mortality and showed that newly developed PCR detection method was useful for pathogen monitoring.