• Development and Reproduction
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• v.25 no.1
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• pp.33-41
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• 2021

This study was carried out to observe the development of the autonomous skeletal development of the Favonigobius gymnauchen. Total length (TL) of larvae 3 days after hatching (DAH) were mean TL of 3.34 mm, with a line-shaped parasphenoid ossification in the cranium and basioccipital ossification in the back. The 10 DAH larvae had a mean TL of 5.20 mm, with the number of caudal vertebrae increasing to 15. The urostyle and two hypural bones in the lower part also began to ossify. The 23 DAH juveniles had a mean TL of 8.47 mm. The pectoral girdle's skeleton was completed as the scapula and coracoid were ossified. The pelvic girdle also fully supported the ventral fin as its ossification was completed. Favonigobius gymnauchen and Tridentiger obscurus showed similar characteristics in terms of the anus location of hatched larvae, number of myotomes, and melanophore distribution during the morphological development of the larvae and juveniles. However, this study confirmed differences in the development of the vertebrae and urostyle bone.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.967-972
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• 2022

We investigated the molecular and morphological traits of 338 individual macrourids collected from the Southern Ocean (FAO area number, 88.1 and 88.3) between 2021 and 2022 by Korean bottom trawls. We first identified them as Macrourus caml and Macrourus whitsoni based on morphological traits, such as the number of pelvic fin rays (PF) and the rows of lower jaw teeth (LJT). However four individuals showed uncategorizable morphological characteristics such as PF and LJT numbers that overlapped between the two species. Subsequently, we obtained and analyzed 509 bp of the mtDNA COI sequences of 49 individuals, including the four unidentified individuals, and found only one single nucleotide polymorphism (SNP) that distinguished the two species. Finally, using our molecular identification key, we confirmed that each two individuals were misidentified as M. whitsoni and M. caml reversely. Our results suggest that the number of PF and LJT should be investigated together to accurately identify the two species.

• Korean Journal of Ichthyology
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• v.25 no.2
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• pp.53-58
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• 2013

Seven individuals (16.1~29.1 mm in length) which were estimated with fishes of genus Abudefduf were collected in Seogwipo, Jeju Island in the summer of 2011 and 2012. Among them, five individuals (20.8~29.1 mm SL) are similar to Abudefduf notatus, based on morphological characters such as yellow transverse band on the body, one small black spot on the base of the pectoral fin, and yellow caudal fin. On the other hand, two individuals (16.1 mm, 17.0 mm SL) differ from them in several light transverse bands and transparent rays of all fins except for pelvic fin, and anterior transparent head with only one (16.1 mm). According to the results of molecular analyses of 578 base pairs of mtDNA 16S rRNA sequences, these individuals correspond to A. notatus adult, with a high bootstrap value of 95% (genetic distance, d=0.002). Therefore, this study shows that the individuals more than 20.8 mm similar to adult body color but the 16.1 mm individual differs to that of adult. We confirm that this species changes to body color during their early life stages. This result regards as a survival strategy to protect themselves against their predator during their early life stages.

• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.205-216
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• 2018

Taxonomic review of the genus Saurida, belonging to the family Synodontidae, was conducted based on three species (S. macrolepis, S. microlepis and S. wanieso) collected from Korea between 1994 and 2017, and one species (S. elongata) loaned from Japan. S. wanieso can be readily distinguished from S. tumbil by following characteristics: outer palatine teeth (2 rows in S. wanieso vs. 3~4 rows in S. tumbil) and pectoral fin length (reaching to pelvic - dorsal line in S. wanieso vs. not reaching to pelvic - dorsal line in S. tumbil). In counts, the four Saurida spp. are well distinguished: number of lateral line scales (48~50 in S. macrolepis vs. 54~58 in S. wanieso vs. 61~62 in S. elongata vs. 63~70 in S. microlepis), vertebrae (47~49 in S. macrolepis vs. 51~53 in S. wanieso vs. 57~59 in S. elongata vs. 62~64 in S. microlepis). The present study suggests S. undosquamis and S. tumbil must be absent in Korean waters, and also S. elongata may be rare or absent in Korean waters. Here we use the Korean name, "tum-bil-mae-tung-i" for S. wanieso, following Yamada et al. (1995) who treated Korean S. tumbil as S. wanieso.

• Development and Reproduction
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• v.18 no.2
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• pp.79-87
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• 2014

In Pleuronectiformes, blind-side malpigmentation (hypermelanosis) is common in cultured flatfishes, and is economically important. To understand the mechanism of blind-side hypermelanosis in flatfishes, we examined when the malpigmentation initially occurred, and studied how the symptoms proceeded during early development of the starry flounder, Platichthys stellatus. To assess quantitative pattern changes of blind-side skin, we observed morphological development of the whole body from 22 (total length [TL] $10.0{\pm}0.2$ mm and body weight [BW] $8.8{\pm}0.57$ mg) to 110 days (TL $23.4{\pm}0.7$ mm, BW $193.6{\pm}23.3$ mg) after hatching (DAH), and also examined the malpigmented area rate of blind-side skin and the malpigmented fish ratios. The experimental animals were reared in fiberglass-reinforced plastic (FRP) tanks in water at a temperature of $18.9{\pm}1.9^{\circ}C$ and salinity of $32.6{\pm}0.6$ psu and were fed with rotifer and Artemia nauplii from 22 to 48 DAH, and with A. nauplii and commercial feed from 49 to 110 DAH. As results, the first staining patch seen by the naked eye was observed around the area between the anus and pelvic fin or caudal edge of the trunk at 80 DAH (TL $20.6{\pm}0.5$ mm, BW $112.5{\pm}8.8$ mg). The pigmented area and the pigmented fish ratios were significantly increased from 80 to 110 DAH. These results indicated that malpigmentation on the blind side of starry flounder was initially observed at about 2 cm in length and 100 mg in weight, and the pigmented domain on the blind-side skin was continually broadened by the differentiation of pigmented cells (melanophores and xanthophores) with growth.

• Development and Reproduction
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• v.2 no.1
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• pp.81-87
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• 1998

A scanning electron microscopic study on the glochidial encystment and excystment during the development of Anodonta arcaeformis flavotincta on Carassius auratus, a common natural host fish, was carried out. The glochidia were attached to the fins, buccal cavity and gills of the host fish within 30 minutes. In this study, the fins of host fish infected with the glochidia were examined in a time series. The attachment rates of the glochidia on the pectoral fins, caudal fin and pelvic fins of the host fish were 30%, 22%, and 17%, respectively. The glochidia which attached to the fish became encysted within 27 hrs. The process of encystment progressed slowly. Ti took 24 to 27 hours in the formation of the primary cyst, and after 5 to 6 days, the larvae was covered completely with the epithelial cels of the host tissues. The process of detachment of juvenile clam was observed on the 8th day after host infection. Most of the juvenile clams have sloughed from the cyst of the host within 15 days. No significant size difference was observed in the glochidia and the juvenile which were found before attachment and after detachment from the cyst of the host fish.

• Korean Journal of Ichthyology
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• v.10 no.2
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• pp.231-240
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• 1998

The characteristics of cranium, vertebral column and fin supports of Acanthorhodeus gracilis were examined. The fish did not have a fontanell in cranium nor process of supraethmoid. It had double orbitosphenoids and a basioccipital process developed from anterior portion of basioccipital. It had a high and triangular dorsal process on supraoccipital. In the urohyal, hypohyal attachment was bifurcated and horizontal and vertical plate were in an elongated rhombus shape with posterior edge pointed. It had teeth of 1-rowed, 5/5 and 4 free teeth. The fish did not have a coracoid foramen on shoulder girdle. It does not have a uroneural on ural centrum. It had a long and slender posterior process of pelvic bone. It had a large and flat supraneural. The fish had 14 or 15 interneural spines, of which the 1st, 2nd, 3rd and 4th had single basiosts and the rest had double basiosts. It had 11 or 12 interhemal spines, of which the 1st, 2nd, 3rd and 4th had single basiosts and the rest had double basiosts.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.201-205
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• 2010

One specimen of a natural hybrid of an Oplegnathus (Oplegnathus fasciatus $\times$ Oplegnathus punctatus) was found in Tongyeong, Korea in August 2008. We, herein, describe its morphological and genetic characteristics and compare them with those of O. fasciatus and O. punctatus. In morphology, the hybrid showed many distinctive black rounded blotches on body sides and four faint vertical bars, being in those features similar to O. punctatus. Although the counts and measurements of the hybrid mostly overlapped between O. fasciatus and O. punctatus, the Oplegnathus hybrid resembled O. punctatus in the ratio of pelvic-fin length in standard length: Oplegnathus hybrid (26.7%) was closer to O. punctatus (26.4%) than to O. fasciatus (17.2~23.6%). In genetics, as a result of analysis of 510 base pair sequences of mitochondrial DNA 16S rRNA, the hybrid was closer to O. fasciatus (d=0.000~0.010) than to O. punctatus (d=0.020). Our results suggest that the natural hybridization represented by the subject specimen occurred between an O. fasciatus female and an O. punctatus male.

• Korean Journal of Ichthyology
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• v.34 no.4
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• pp.277-287
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• 2022

Two sculpin specimens (79.3~100.8 mm standard length) were collected from the upper reach of Deokdongcheon Stream, a tributary of the Hyeongsangang River, in Korea. They were identified as Cottus pollux by characteristics such as the absence of palatine teeth, 12~13 unbranched pectoral fin rays, pelvic fins without obvious bands or spots, and the absence of a blackish band on the head or anterior part of the body. A phylogenetic analysis based on the nuclear ITS1 gene and mitochondrial cytb gene indicated that the specimens formed a clade with Japanese C. pollux, supporting the morphological species identification. We propose a new Korean name for the species: "Min-mu-nui-dug-jung-gae"

• Korean Journal of Ichthyology
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• v.35 no.3
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• pp.201-206
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• 2023

A single specimen of the genus Plectorhinchus (Family: Haemulidae) was collected from the coastal waters around Jejudo Island on November 1, 2017 by a longline. The specimen was identified as Plectorhinchus vittatus by the morphological characters as follows: eight black vertical stripes on the body, scattered polka dots on the dorsal, anal and caudal fins. It is clearly distinguished from the congeneric species, P. lineatus, which is morphologically very similar to P. vittatus, in the number of gill rakers, stripes on the abdomen, and black patterns on the base of the pelvic fin. In this study, the occurrence of this species has been newly revealed at higher latitudes, suggesting the expansion of the northern distribution limit. Following Lee et al. (1999), we propose its Korean name as "Chu-sa-eo-reum-dom".