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ISSN : 1225-3480
In this study, two specimens of the triphorid species Euthymella concors (Hinds, 1843) were collected during a SCUBA survey on Jeju Island and are newly recorded in the Korean fauna. To date, 20 species in the family Triphoridae have been reported from Korean waters. Herein, we provide additional information about E. concors, including its morphological description, images of the shell and mitochondrial cytochrome c oxidase subunit I (cox1) partial sequence.
This study documents the first records of the family Cuthonellidae and the genera Cuthonella and Tenellia from Korean waters. Five nudibranch species previously unrecorded in Korea were identified: Cuthonella georgstelleri, Cuthona futairo, Tenellia melanobrachia, Tenellia zvezda, and Tambja morosa. Each species was redescribed based on distinctive morphological characteristics, and underwater photographs of living individuals were provided. To evaluate genetic divergence, mitochondrial cytochrome c oxidase subunit I (COI) sequences were analyzed for four of the five species. The calculated intraspecific p-distances were 0.6% in C. futairo, 0-1.5% in T. melanobrachia, and 0.6-1.7% in T. zvezda, while T. morosa exhibited considerably higher intraspecific variation (0.3-11.7%). These results offer a useful molecular reference framework for future integrative taxonomic investigations of nudibranchs in the Northwest Pacific.
This research investigated Perkinsus olseni infection patterns in clams from two geographically distinct regions: Korean Manila clams (Ruditapes philippinarum) and Portuguese carpet shell clams (R. decussatus). Specimens were collected from Gochang, Korea and Olhão, Portugal for comprehensive molecular and histopathological analysis. PCR diagnostics demonstrated a striking disparity in infection prevalence, with Korean clams exhibiting a 95.0% infection rate compared to only 33.3% in Portuguese specimens. Genetic characterization through ITS sequence analysis revealed significant phylogenetic differentiation, with Korean isolates clustering within Asian lineages while Portuguese isolates aligned with Atlantic lineages. Histopathological examinations further substantiated these regional differences, as Korean samples displayed widespread infection across multiple tissue types with pronounced inflammatory responses, whereas Portuguese samples showed only localized, mild infection restricted to gill tissue in a single specimen. These marked regional variations in infection patterns likely stem from a complex interplay of environmental factors, host-specific susceptibility differences, and pathogen virulence characteristics. This study provides critical insights into the regional epidemiology of P. olseni infections and emphasizes the importance of developing region-specific approaches for understanding and managing host-pathogen dynamics in marine bivalve populations.
Size and growth-line analyses were carried out on 586 hard clam (Meretrix petechialis) from the Neolithic Age Daejuk-ri Shell Midden, Seosan-si, Korea, to examine the gathering patterns of the past. The maximum shell length of the clam was distributed between 33.81-70.54 mm. The age of the clam ranged from 2 to 5 years. The sizes and ages of the collected hard clams varied, so it seems that there was no preference for a specific size and age. 578 (98.6%) out of 586 specimens represented spring while 8 (1.4%) specimens represented summer collection, suggesting that they were collected intensively in spring when food resources were scarce and they were in season.
This study was conducted to investigate the possibility of the September cohort of a bay scallop can reach to a commercial size and can avoid the biofouling and shell-boring impacts by overwintering cultivation. For these purposes, we compared the growth pattern of a bay scallop (Argopecten irradians) cultivated during the winter season from Nov. 2023 to March 2024 submerged in August and September, 2023 in Jaran Bay, the southern coast of Korea. There were significant differences in all biological parameters of scallops such as mean body weight, mean shell weight and mean wet meat weight between two cohorts submerged in August and September during winter season, but the September cohort could reached up to 80% of the commercial size in March and April. Thus the winter-spring landing of cultivated scallops could be a harvesting strategy by controlling the amount of landing through winter season and early spring not concentrating the single landing in late autumn for the conservation of the landing price of cultivated scallops.
