• Korean Journal of Ichthyology
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• v.24 no.2
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• pp.125-130
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• 2012

We describe early morphological development in laboratory-reared specimens of the brown croaker, Miichthys miiuy, in relation to fin differentiation, head dimensions, and squamation. From the yolk sac stage to the flexion larval stage (a period of 12 days following hatching, at which time the larvae were <4.2 mm in total length; TL) we observed the presence of a fin-fold around the body, while the caudal fin appeared rounded and lacked scales. Rays developed in the dorsal, anal, and pectoral fins in a process that was almost complete in larvae 12 days, while ray segmentation occurred between 26 and 29 days of age. Elongation of the middle rays of the caudal fin was initiated at 32 days, and the rays were remarkably elongated by 37 days. By 68 days the caudal fin was lanceolated (50.7 mm TL). Scales began to develop from the midlateral lines of the caudal peduncle at 9.1mm TL (28 days), eventually encompassing the entire operculum (22.1 mm TL; 44 days). The head dimensions were largely stabilized at >12 mm TL (30 day).

• Development and Reproduction
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• v.20 no.2
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• pp.51-63
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• 2016

The landmark-based morphometric and meristic analysis of the kelp grouper (Epinephelus bruneus), red spotted grouper (E. akaara) and seven-banded grouper (E. septemfasciatus) were performed to compare the differentiation of overall body shape and structure. The measurements of the morphometric dimensions were observed in 25 parts (truss dimension: 16 parts; head part dimension: 9 parts) of 38 morphometric dimensions and also meristic differences observed in 3 parts (dorsal fin, anal fin and caudal fin) of 6 meristic counts (P < 0.05). Observed morphometric characteristics primarily involved in truss and head part dimension, kelp grouper have larger values in caudal part of truss dimension, kelp grouper, red spotted grouper and seven-banded grouper have similar values in pectoral part of truss dimension, in addition to, results of head part dimension showed that red spotted grouper have smaller values in overall dimensions (P < 0.05). As meristic characteristics, kelp grouper have more number of anal fin rays than other fish, red spotted grouper have more number of dorsal soft rays than other fish, and seven spotted grouper have more number of anal soft rays, and caudal fin rays than other fish (P < 0.05). Photographed under the x-ray, kelp grouper have the most curved vertebral column and largest swim bladder than other fishes (P < 0.05). Our results of this study confirmed that 3 subfamily fishes adequately can distinguish with external body shape, and we hope that the results of our study could be used to identify in Serranidae family as taxonomical parameters.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.3
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• pp.271-282
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• 2012

Early osteological development of the skull, vertebral column, and fins, and squamation in the spotted sea bass, Lateolabrax maculates, were studied under extensive larval rearing conditions. The first ossification during cephalic skeleton development began with the premaxillary, dentary, and parasphenoid at 6.4 mm Total length (Notochord length 6.1 mm) and was completed by 25.2 mm TL (Standard length 20.3 mm). Ossification of the cartilaginous caudal complex started simultaneously in the urostyle and two preural centra at 12.2 mm TL (10.4 mm) and it was completely ossified by 32.0 mm TL (26.4 mm). The principal caudal fin rays, with a count of 9/8, began to ossify at 11.6 mm TL (10.2 mm) and the procurrent caudal fin rays, with counts of 4 (upper) and 3 (lower), started to ossify by 12.6 mm TL (10.9 mm). Ossification of these parts was completed by 21.4 mm TL (17.5 mm). Ossification of the vertebral column was first observed in the first to fourth centra at 8.3 mm TL (7.5 mm) and was fully completed by 21.7-35.0 mm TL (17.8-29.3 mm). The pectoral girdle started to ossify by 5.6 mm TL (5.4 mm) and was completed by 26.8 mm TL (21.8 mm). Eight pectoral fin rays were ossified at 11.6 mm TL (10.2 mm) and 16-18 rays were fully ossified by 13.8 mm TL (12.0 mm). Also, the dorsal, anal, and pelvic fin rays started to ossify at 12.2 mm TL (10.4 mm) and were completed by 12.8 mm TL (11.2 mm), 23.8 mm TL (19.4 mm), and 13.8 mm TL (12.0 mm), respectively. Ossification of the anal and dorsal pterygiophores initially occurred by 12.6 mm TL (10.9 mm) and 14.3 mm TL (12.2 mm), and was completed by 21.4 mm TL (17.5 mm) and 19.3 mm TL (15.9 mm), respectively. Squamation started at three centers of differentiation: the middle region of the trunk, the anterior of the caudal peduncle, and on the caudal peduncle at 23.8 mm TL (19.4 mm). The body was covered with scales, except the snout, at 57.2-60.2 mm TL (SL 47.1-49.2 mm).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.1
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• pp.52-58
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• 2014

Morphological and genetic variation of two populations of Platichthys stellatus were investigated based on 30 individuals each, collected from Uljin (seedling release area) and Pohang (control) in Korea. Morphological analyses demonstrated that the two populations of P. stellatus were well distinguishable in body color of the blind side and fin shape. Mitochondrial DNA control region analysis indicated no significant differences between the two populations ($F_{ST}=-0.00849$, P>0.05). We also analyzed microsatellite DNA loci of the two populations using six markers. Observed heterozygosity ($H_O$) and expected heterozygosity ($H_E$) were 0.550 and 0.592, respectively, in P. stellatus from Uljin, but 0.700 and 0.737 in P. stellatus from Pohang. An index of differentiation in genetic structure revealed significant differences between the two populations ($F_{ST}=0.0208$, P<0.05). Our results suggest that the Uljin population may be comprised of released P. stellatus, whereas the Pohang population may be wild P. stellatus, highlighting the necessity of continuous monitoring of the two populations.

• Animal cells and systems
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• v.1 no.4
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• pp.529-534
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• 1997

Genetic and morphological variations of Rhinogobius giurinus were surveyed. Populations of R.giurinus were clearly divided into two forms (Form-A and Form-B). Starch gel variation of this species. Three loci (Aco, Mpi, aGpd) out of 27 showed fixed allelic differences between Form-A and Form-B and they are well differentiated from each other genetically (Rogers' S=0.871). These two forms, moreover, are found to be allopatric in distribution and morphologi cally different in body length and caudal fin color pattern. Therefore, they are considered as two distinct taxa of subspecific rank. In addition, the genetic relationships among 5 taxa within 4 species of the genus Rhinogobius were investigated. Three species of the Rhinogobius brunneus complex (R.sp. OR, R. sp. CB and R. sp. CO) are well differentiated from each other genetically and two taxa of R. giurinus are genetically divergent from three species of the Rhinosotius brunneus complex (average Nei's D=0.603, average Rogers'=0.534).

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.199-209
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• 2020

In order to clarify the taxonomic status of the Korean Macroramphosus species, which were previously confused, we investigated morphological and molecular variations of Macroramphosus (18 individuals) from Korea, and Macroramphosus (35 individuals) from Japan and Taiwan, and compared with those of M. scolopax from type locality (Mediterranean Sea). Although the Korean and Japanese specimens of Macroramphosus were clearly divided into two types in the first dorsal spine length (22.8~32.1% in A-type vs. 15.6~21.4% in B-type), distance between the first dorsal fin and second dorsal fin (6.4~9.7% vs. 8.6~13.3%), and body depth (20.0~28.0% vs. 17.3~22.6%), no genetic differences among all individuals of longspine snipefish between them were found at the specific level [d=0.0~3.3% in control region (CR); 0.0~1.3% in cytochrome b (cytb); 0.0~0.5% in cytochrome c oxidase subunit I (COI)]. Whereas, they were well distinguished in genetics (9.9~11.5% in CR; 3.8~4.6% in cytb; 1.2~3.6% in COI) from those of M. scolopax in Mediterranean Sea. It needs the scientific name of the longspine snipefish (M. scolopax) in Korea be changed as M. japonicus (and/or M. sagifue). However, our results could not find evidence of consistency between morphological and mitochondrial DNA variations which suggests that their differentiation event may occur fairly recently. Further studies using more sensitive markers such as microsatellite are needed to clarify the degree of gene flow between the two types.

• 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.

• Korean Journal of Ichthyology
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• v.36 no.3
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• pp.209-219
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• 2024

A survey was conducted in 2011 to investigate the reproductive ecology and spawning behavior of the natural monumental and endangered species, Cobitis choii. C. choii exhibits sexual dimorphism with the development of lamina circularis on the second pectoral fin ray in males at one year old, facilitating easy differentiation between males and females. A total of 1,288 females and 881 males were collected from January to December, resulting in a sex ratio of 1 : 0.68. The spawning season was estimated to be from late June to early July (spawning peak from late June, with water temperatures ranging from 22 to 25℃), coinciding with a sharp decrease in the condition index. Gonadal maturity was observed with maturity indices of 17.5±2.11% for females and 2.9±0.46% for males, with fecundity of 2,444±838 eggs and egg size of 0.75±0.05 mm. Spawning behavior was induced by hormone injection (Human Chorionic Gonadotropin, HCG) in laboratory conditions. Experimental results revealed that males and females paired in a 1 : 1 ratio before spawning. Males pressed the abdomen of females using their lamina circularis to induce spawning, followed by immediate fertilization. Spawning behavior was repeated 15 to 25 (average 20) times per pair of males and females, and 80 to 120 eggs were spawned per time, and the total amount of spawned eggs were 2,500±250 on average.

• Korean Journal of Ichthyology
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• v.11 no.1
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• pp.94-101
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• 1999

This study was conducted to observe the early life history of sea bass, Lateolabrax japonicus. The fertilized eggs were spherical in shape and turned out to be separative and floated. Their membrane and yolk having 1~5 oil globule were transparent. Fertilized eggs were measured to be 1.33~1.46 mm in diameter. Hatching of eggs were started at 74 hrs 15 mins, 54 hrs 55 mins, 50 hrs 45 mins, after fertilization in water temperature $16.0^{\circ}C$, $18.0^{\circ}C$, $20.0^{\circ}C$ respectively. The newly hatching larvae were 3.79~3.97 mm in total length with 35~37 myomeres, and mouth and anus were closed. Melanophores were distributed on the up side of head, upper jaw and margins of the body. The 5 days after hatching larvae measured 4.78~5.24 mm in total length, yolk were completely absorbed, and transformed to postlarval stage. In this time, mouth of larvae was opened, and also melanophores were presented on the lower jaw. Head of larvae grew remarkably. The 21~22 days after hatching, total length of the larvae was 7.15~8.12 mm, the caudal fin rays began to differentiation. In 31 days after hatching, the larva were 8.46~9.16 mm in total length, and tip of the caudal notochord flexed $45^{\circ}$. The larvae reached to the juvenile stage with all the fins were developed at 61 days after hatching and attained 16.28~17.31 mm in total length.