• Journal of Aquaculture
• /
• v.19 no.4
• /
• pp.236-241
• /
• 2006

Seasonal variation of the infection by three species of symbiotic copepods in clam, Tresus keenae was investigated in south coast of Korea. The prevalence and abundance of three symbiotic copepods showed seasonal variation with a peak in winter. Reproduction of the copepods occurs from early autumn to spring as indicated by higher ratio of gravid copepods. The frequency distribution of Lichomolgus inflatus, Pseudomyicola spinosus and Anthessius progectus in their host population could be fitted with negative binominal distribution. Results from the present study suggest that seasonal fluctuation in prevalence, relative density and mean intensity is related to temperature and life history of the symbiotic copepods.

• Animal Systematics, Evolution and Diversity
• /
• v.38 no.4
• /
• pp.167-198
• /
• 2022

Ten species of copepods, including nine new species, associated with compound ascidians are recorded from Korean waters. Nine new species can be characterized by their major diagnostic features, as follows: Botryllophilus pentamerus n. sp. by having a five-annulated abdomen; B. paucisetatus n. sp. by the presence of four and three setae on the exopods of right and left leg 1, respectively; Haplostoma quadridens n. sp. by the presence of four lobes on the labrum and one seta plus four spines on the exopods of legs 1-4; H. paucidens n. sp. by the presence of only two spines on the distal segment of the antenna; Enterocola horridus n. sp. by having five setae on the antenna, no seta on the caudal ramus, and two setae on leg 5; E. longicaudatus n. sp. by having long caudal rami which are more than three times as long as wide; Thoracodelphys bisetata n. sp. by the presence of only two setae on the basis of the maxillule; T. cerasta n. sp. by the presence of a large, horn-like process on the distal margin of the basis of leg 2; and Unimeria hirsuta n. sp. by having three setae on the terminal segment of the maxilla. Zygomolgus didemni (Gotto, 1956) previously known only from European waters is reported from Korean waters, with a redescription and illustrations.

• Journal of Species Research
• /
• v.13 no.2
• /
• pp.185-254
• /
• 2024

Sixteen species of Asterocheres collected from the southern and eastern coasts of Korea are recorded. Two species are redescriptions-Asterocheres aesthetes Ho, 1984 and A. siphonatus Giesbrecht, 1897. The remaining 14 new species described are A. geminus n. sp., A. processus n. sp., A. culicis n. sp., A. eurychelatus n. sp., A. scutellatus n. sp., A. spiniventer n. sp., A. fici n. sp., A. serratus n. sp., A. tridentatus n. sp., A. nodulosus n. sp., A. tetraodontis n. sp., A. dokdoicus n. sp., A. exilis n. sp., and A. zodius n. sp. These new species are compared with other known species of the genus mainly based on the character states of 17 selected characters. These characters include the length/width ratios of the caudal ramus and genital double-somite, the number of postgenital lateral setules or spinules on the genital double-somite of the female, the number of segments of the antennule of both sexes, the position of aesthetasc on antennular segments in the female, the relative length of terminal claw of the antenna, the relative length of the oral siphon, the number of segments and the relative length of the mandibular palp, the presence or absence of inner coxal seta on legs 1 and 4, the relative lengths of setae on the exopod of female leg 5, the presence or absence of sexual dimorphisms of swimming legs, and the presence or absence of a secondary aesthetasc on the male antennule. A key to 22 species of Asterocheres known in Korea waters is provided.

• Ocean and Polar Research
• /
• v.36 no.2
• /
• pp.121-134
• /
• 2014

Sessile marine bivalves including mussels, oysters and clams are often used as a sentinel species in coastal environmental monitoring since changes in the environmental quality are often well preserved in their tissues and shells. In this study, we investigated overall health condition of the Mediterranean Mussel, Mytilus galloprovincialis on the south coast using histology. Reproductive condition as gonad index (GI), condition index (CI) as a ratio of the tissue weight to the shell weight, digestive gland atrophy (DGA), types of parasites, and pathologic conditions including erosion, necrosis, hemocyte infiltration, and neoplasia were examined from each histological preparation. GI decreased from March to July then increased from July to September and spawning mussel could be observed as early as in April and the activity continued until September. CI also followed the monthly changes in GI, indicating that decrease in CI was associated with the weight loss due to spawning. DGA increased from March to June, decreased in July and increased from July to September. High DGA values observed in June and September were coincided with spawning and high water temperature. Histology also showed high prevalence of erosion in the digestive gland in June (36.0%) and September (56.4%), suggesting that high water temperature and spawning acted as environmental stressors. No parasitic organism was identified during the survey, although some symbiotic copepods were observed. Histology was found to be useful and affordable technique in monitoring the overall health of mussel, providing useful pathologic information of the cells and tissues.