• Korean Journal of Ichthyology
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• v.17 no.4
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• pp.229-235
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• 2005

Sexual maturity of Korean skate, Raja koreana, was investigated based on 89 specimens caught between September 2002 and December 2003 in the southwestern sea of Korea. Clasper development was slow between 35 cm and 52.5 cm TL, increased abruptly between 59.5 cm and 71 cm TL, and thereafter decreased, showing an overall sigmoidal growth pattern. Unlike other skates and sharks, Korean skate males were already histologically mature before the claspers lengthened. Although the egg capsules were found in May and November in Korean skate females, histological findings indicated that spawning occurred throughout the year except summer in females but all the time in males.

• Proceedings of the Zoological Society Korea Conference
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• 1998.04a
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• pp.33-33
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• 1998

The most recent, Jeong and Nakabo (1997) described Raja koreana as a new species based on an adult female specimen collected from the southwestern coast of Korean Peninsula. Raja koreana has several unique characters not shared with any other supraspecific taxa of Rajoidei, but it was provisionally included in the genus Raja because of having no information of its clasper. Later, two mature males and a few specimens of the species were collected from near the type locality. Therefore, a new genus should be erected for this species. The new genus is characterized by the followings: Rostral shaft straight, narrow and thick in depth: unsegmented base with filamentous cartilage. Dorsal surface of tail with a row of distinct thorns along midline, patches of distinct thorns anterior to first dorsal fin and between first and second dorsal fins in bathe sexes; most thorns directed anteriorly, and thornlets directed posteriorly. Scapulocoracoid comparatively short and high, rear corner high, without anterior bridge, postventral fenestra expanded. Distal tip of accessory terminal 1 claspser cartilage well separated from the tip of accessory terminal 2 clasper cartilage.

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.198-210
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• 1999

Based on the reviewing the present specimens and published data, taxonomic revision about the Korean names and distributional ranges of the rajid fishes (Rajidae) in Korea was conducted. As a result, the family Rajidae from Korea was classified into 4 genera encompassing 11 species, Bathyraja bergi, B. isotrachys, Dipturus kwangtungensis, D. macrocauda, D. tengu, Okamejei acutispina, O. boesemani, O. kenojei, O. meerderooortii, Raja koreana and R. pulchra. Proposed new Korean names are "Salhongeo-sok" for the genus Dipturus and the "Hongeo-sok" for the genus Okamejei, because those are elevated from subgeneric to generic rank recently. In particular, the new korean names are needed to be given that, the genus Raja is "Chamhongeo-sok" and R. pulchra is "Chamhongeo". The occurrence of Bathyraja bergi is recognized as in the Korean waters according to this revision. The check list and the map of geographic distributions of 11 species of Rajidae from Korea are presented.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.2
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• pp.103-114
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• 1992

Diurnal and seasonal variation of demersal fishes of Asan Bay were studied using seasonal samples collected by an otter trawl from autumn 1989 to summer 1990. For each sampling period, three to five trawl hauls were completed to obtain day and night samples. Of 32 species identified, Chaturichthys stigmatias, Cynoglossus joyneri, Thrissa koreana, Repomuenus lunatus and Hexagrammos otakii accounted for $79.5\%$ of the individuals collected, and C. joyneri, T koreana, H. otakii, Raja kenojei and Kareius bicoloratus constituted $67.1\%$ of the biomass obtained. Apparently, larger number of individuals and greater biomass were collected in night hauls. However, there is no significant difference between day and night samples in community structure, mean abundance and body length of the dominant demersal species. The greatest numbers and biomass of fishes were collected in summer and the lowest in winter. The abundance of fishes in the study area were dependent upon seasonal effects such as temperature.