• Korean Journal of Ichthyology
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• v.36 no.1
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• pp.94-100
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• 2024

During ichthyoplankton survey in the southwestern sea of Korea, we collected six individuals of noodlefish larvae and juveniles between April and May 2023. They were identified as Neosalanx anderssoni by mitochondrial DNA cytochrome c oxidase subunit I or 16S ribosomal RNA sequences, and their external morphological traits were described for the first time. All six individuals have a slender and elongated body. When preflexion and flexion larval stages (10.24 mm notochord length, NL and 15.47 mm total length, TL, respectively), oval-shaped black melanophores were distributed in a row along the ventral side of the gut. However, when postflexion larval and juvenile stages (23.58~25.90 mm TL, and 29.20~31.26 mm TL, respectively), melanophores on the ventral side of the gut were disappeared, and dark spot-shaped melanophores appeared along the dorsal side of the gut in a single row. Also, from the postflexion larval stage (23.58 mm TL), two large black spots began to appear symmetrically on the caudal fin. Our results suggest that N. anderssoni may use coastal area as spawning and/or nursery ground unlike previous study (Kim and Park, 2002).

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.168-178
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• 2010

Fish assemblages associated with rock reef and non-rock reef were studied using specimens collected at three sites in Geomun Island waters of the Southern Sea, Korea, in February, May, August and October, 2006. Two survey methods for the study were followed: collection by a gill net, and video observation by scuba diving. The gill-net survey was conducted during the night, the scuba-diving observations were conducted during the day. From the gill-net survey, a total of 40 species, 380 inds. and 71,426.9 g was caught at the three sites. The dominant species was Trachurus japonicus; other species were Raja kenojei, Dasyatis akajei, Stephanolepis cirrhifer, Narke japonica, Pagrus major, Sebastes inermis, and Sphyraena pinguis. At the rock-reef site, a total of 26 species, 264 inds. and 46,776.7 g was caught by gill net, and the dominant species was T. japonicus. A total of 17 species, 45 inds., 10,535.1 g was caught at the flat-bottom 1 site, and 19 species, 71 inds. and 14,115.1 g were caught at the flat-bottom 2 site. The scuba-diving survey resulted in 13 species and 1,749 inds. observed at the three sites through the survey period. The main observed fishes were rock-dwelling species such as Chromis notatus, Microcanthus strigatus, S. cirrhifer, Ditrema temmincki, Evistias acutriostris, Girella punctata, Halichoeres poecilopterus, Hexagrammos agrammus, Prionurus scalprum, Sebastes inermis, and Semicossyphus reticulatus. Seven species and 1,739 inds. observed at the rock-reef site comprised 99.4% of the inds. of the three sites. Therefore, the fish community in Geomun Island waters included many rock-reef. species, but a few were migratory species like T. japonicus and Scomber japonicus. The abundance of fish at the rock-reef site was high in comparison with those at two non-rock reefs. The dominant species were very different between the day and the night, although rock-reef species comprised the main part of the fish community. We conclude that the high abundance of fish in Geomun Island waters is most closely related to physical structure, such as rock reefs, which is the main habitat of many fishes.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.263-269
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• 2023

This study aims to contribute to the research on resource recovery for the rapidly declining population of Liparis tanakae by observing the larval development process and the morphology of juveniles based on their growth. Natural spawning eggs collected in Yeosu were used for observing the process of egg development and larval morphology. The water temperature during the rearing process was maintained at 12.3~13.5℃ (average 12.7℃). The fertilized eggs had an egg diameter ranging from 1.57 to 1.79 mm (average 1.71 mm) and were spherical and adhesive. Within 4 hours 35 minutes after fertilization, they reached the two-cell stage, and after 74 hours 10 minutes, the formation of the yolk sac began. At 106 hours post-fertilization, a caudal fin appeared at the tail tip. Hatching began at 526 hours, and the larvae developed with the yolk sac positioned just behind the eyes. The newly hatched larvae had both the mouth and anus open. Melanophores appeared inside the lower jaw and around the tail on the third day after hatching. By the 16th day after hatching, most of the yolk was absorbed, and melanophores were visible in the head region. Finally, on the 63rd day after hatching, the head region significantly developed, and the body shape and mouth were similar to those of an adult fish, signifying the transition to the juvenile stage. This study will serve as valuable data for aquaculture techniques related to the conservation and restoration of fish species based on the hatching and juvenile morphology of Liparis tanakae.

• Korean Journal of Ichthyology
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• v.36 no.3
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• pp.273-281
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• 2024

In June and July 2023, a total of 101 Thryssa kammalensis larvae and juveniles were collected during an ichthyoplankton survey using RN80 in the waters around the southwest coasts of Korea. When pre-flexion larval stage (3.77~10.20 mm NL, n=22), some individuals have pterygiophores of dorsal and anal fins, but no apparent fin rays were formed. Line-shaped melanophores were distributed in a row from below the opercle to the anal fin base. When flexion larval stage (12.13~16.69 mm SL, n=14), the number of dorsal and anal fin rays were 13~15 and 18~23. Dot and line-shaped melanophores were distributed in a row in the ventral portion of the abdominal cavity, and melanophores appeared on the caudal fin. When post-flexion larval stage (17.23~21.73 mm SL, n=20), all fin rays appeared, and the number of pectoral, pelvic, anal and dorsal fin rays were 7~9, 4~5, 29~31 and 14~15, respectively. Dot and line-shaped melanophores were distributed in a row from the posterior of the preopercle to the ventral portion of the abdominal cavity, oval-shaped melanophores were distributed along the anal fin base, and melanophores concentrated lower lobe of the caudal fin. When juvenile stage (18.43~25.98 mm SL, n=45), the number of pectoral, pelvic, anal and dorsal fin rays were completed as 12~15, 7~8, 30~33 and 14~15, respectively. Point-shaped melanophores of the ventral position of the abdominal cavity disappeared, it continued in a row along the anal fin base to the lower caudal peduncle. Our results suggest that Thryssa kammalensis may use the sea around Chilsan-do Island as spawning and/or nursery ground between June and July.