• Fisheries and Aquatic Sciences
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• v.21 no.12
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• pp.37.1-37.10
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• 2018

The larvae and juveniles of Porocottus leptosomus belonging to the family Cottidae were collected (n = 95, 3.9-16.5 mm in body length, BL) from Busan, Korea, in March 2015. The larvae and juvenile were identified using DNA barcoding as P. leptosomus, and their morphological description was presented in detail. The yolk-sac larvae (3.9-5.6 mm BL) body was slightly compressed, the head was large, the eye was round and large, and the anus was before the middle of the body. The preflexion larvae (5.2-10.0 mm BL) body length drastically increased; caudal fin rays began to occur. The flexion larvae (9.4-11.8 mm BL) notochord flexion started; dorsal, pectoral, and anal fin rays began to occur; pelvic fin buds are seen; they possessed a pair of parietal spine; and a pair of supraocular cirri was first to develop. At 12 mm BL, the notochord was completely flexed. The larva stage (3.9-12.6 mm SL) had the stellate melanophores in the head, isthmus, gut, and tail (along to the ventral midline). During the juvenile stage (11.4-16.5 mm BL), melanophores covered the head and began to form five black bands on the side of the body. The larvae of P. leptosomus spent pelagic life, but moved to the bottom during the juvenile stage. The larvae and juveniles of P. leptosomus differ from other cottid larval fishes by body shape, melanophore head pattern, and spine development. P. leptosomus can be distinguished from Porocottus allisi by morphological development and the occurrence of larval fish: preopercular spine development, melanophore pattern, and caudal fin development.

• Korean Journal of Ichthyology
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• v.21 no.sup1
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• pp.74-74
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• 2009

The perciform suborder Labroidei comprising six families (Cichlidae, Embiotocidae, Pomacentridae, Labridae, Odacidae, and Scaridae) are characterized by having the specialized pharyngeal jaws for food processing, i.e., united fifth ceratobranchials and upper pharyngeal jaw articulating with the basicranium via diarthroses (Stiassny and Jensen, 1987). They usually inhabit in the most tropical and subtropical seas and comprise about 235 genera and roughly 2,274 species worldwide (Nelson, 2006). Concerning the Korean labroid fishes, Mori (1952) had listed 18 genera and 26 species belong to four families in his check list of Korean fishes since Jordan and Metz (1913) firstly reported six genera and seven species in only two families (Embiotocidae and Labridae). Chyung (1977) added two species, Tilapia mossambica and Cirrhilabrus temmincki, to Mori’s list and also classified them into three suborders, i.e., Embiotocina (containing only Embiotocidae), Pomacentrina (Cichlidae and Pomacentridae), and Labrina (Labridae and Scaridae). Subsequently, Lee and Kim (1996) reviewed the Korean labroidfishes taxonomically resulting in 22 genera and 32 species in five families with some taxonomical modifications including a new Korean record. It is remarkable to be added many new Korean recordsto the pomacentrids or the labrids for recent 10 years (Koh et al., 1995; Yoo et al., 1995; Koh et al., 1997; Myoung, 1997; Choi and Kim, 2000; Choi et al., 2002; Kim and Go, 2003). Recently, Kim et al. (2005) briefly described all members of the Korean Labroidei with a color photograph or a figure, recognizing 27 genera and 42 species in five families. In the present study, the current taxonomical status of the Korean labroid fishes including distributional features is summarized based both on specimens collected from the Korean waters and on literature survey to provide bio-information of the Korean native fish species. As a result, the Korean labroid fishes totally consist of 27 genera and 44 species in five families, that is, Cichlidae (1 species), Embiotocidae (3), Pomacentridae (15), Labridae (22), and Scaridae (2). They distributed mainly in the coastal waters of the South Sea, Korea, however, most pomacentrids or labrids occur in the coastal waters of Jeju Island only, although some species were observed in their larval or juvenile stages only from coastal waters of the island. Interestingly, several species are expanding their distribution north to Ulreung and Dok islands in the East Sea, Korea lately.

• Korean Journal of Ichthyology
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• v.19 no.2
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• pp.132-141
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• 2007

A total of 27 fish species were collected by a gill net in Masan Bay. The dominant fish species were Konosirus punctatus, Mugil cephalus, Engraulis japonicus, Psenopsis anomala, Lateolabrax japonicus, Leiognathus nuchalis, Chelon affinis, Trachurus japonicus, and these accounted for 87.6% of the total numbers. The numerically dominant fish species made up 95.4% of biomass. These were primarily juvenile species or early larger species. Temporal variation in both species composition and abundance was large: the peak number of fishes occurred in March 2005 and July 2005, whilst biomass of fishes was the highest in September 2005 and November 2005. Fish numbers as well as biomass was lowest in November 2005. Temporal changes in the abundance of fishes corresponded with temperature. A gill net can be used as an alternative fishing gear to collect pelagic fishes commercially, although a gill net has a strong selectivity for the target fish species or for size.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.4
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• pp.406-412
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• 2014

To evaluate the influence of burrowing substrate on the rearing performance and ambicoloration of cultured flounder, Paralichthys olivaceus, we compared the daily food intake (DFI), feed efficiency (FE), survival, growth, proportion of pigmented skin on the blind side, and proportion of ambicolored fish. We reared juvenile flounders [total length (TL) $4.46{\pm}0.06cm$, body weight (BW) $0.77{\pm}0.03g$] in dark-green fiberglass-reinforced plastic (FRP) aquariums without (control) or with gravel substrate at a density of 200 fishes/ton for 120 days. While there was no difference in survival rate or growth, the DFI was lower and FE higher in the group raised with substrate than in the control. The proportions of pigmented area on the blind side and ambicolored fish were significantly higher in the control tank. Therefore, the supplement of substrate on the aquarium bottom positively affects the feeding efficiency, and inhibits abnormal pigmentation on the blind side in flounder farming at high density.

• Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.317-323
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• 2009

Waste products were biologically estimated from juvenile flounder (Paralichthys olivaceus) on three diet types-raw fish-based moist pellets, moist pellets, and extruded pellets. Total solid and soluble wastes were estimated by determining nutrient digestibility and accumulation in juvenile flounders through growth trials. Total solid wastes produced were 20%-23% of the organic matter supplied. Soluble excretions ranged from 45% to 49%. Soluble nitrogenous excretions ranged from 36.4% to 46.2%. These results indicate that about 30.2%-35.9% of supplied feed is retained in the fishes' bodies while the remainder of feed is excreted into culture systems or the surrounding environment.

• Journal of fish pathology
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• v.34 no.2
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• pp.133-140
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• 2021

With the recent isolation of a new betanodavirus in shellfish, Korean Shellfish Nervous Necrosis Virus (KSNNV), it has also been identified the reassortant KSNNV of two RNA segments, in which one segment is KSNNV genotype but the other one is known genotype. In this study, we confirmed that the ressortant KSNNVs obtained in previous screening study of our laboratory for betanodaviruses in shellfish were KS/RGNNV and RG/KSNNV type by performing two consecutive multiplex RT-PCR on each RNA1 and RNA2 segment (R1- and R2-discriminative multiplex two-step RT-PCR, respectively) to determine the genotype of each segment based on the size of amplicon. In the pathogenicity analysis, none of the reassortants induced specific external symptoms or mortality of VNN, but viruses of 2 × 10⁴~10⁵ copies/mg or more were detected at 14 days after injection (10⁷ copies/fish) in brain tissues of 4 species except for crucian carp and common carp among the 6 species of juvenile fish used. In addition, the histopathological features of weak but distinct vacuole formation were also found in the brain of these infected fish, but no difference was found between the two reassortants KS/RGNNV-KG and RG/KSNNV-CM.

• 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.56 no.1
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• pp.44-53
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• 2023

In this study, the morphological development and early life cycle of larvae and juvenile Rhinogobius brunneus found in Wicheon, Nakdong River, Korea, were investigated. The fertilized eggs were 2.20×0.68 mm (long×short) in diameter. The eggs began hatching approximately 104 h after fertilization at water temperatures of 17.3-20.5℃ (mean 18.9±1.6℃). The newly hatched yolk-sac larvae were 3.71±0.06 mm in total length (TL), with an unopened anus. Three days after hatching, the preflexion larvae were 4.37±0.16 mm in TL with yolk absorption. Twenty days after hatching, the flexion larvae were 6.50±0.22 mm in TL and the tip of the notochord was bent upward. Twenty-seven days after hatching, the postflexion larvae were 11.8±0.63 mm in TL, and the tip of the urostyle was bent at 45°. Forty days after hatching, individuals measured 18.5±0.93 mm in TL and were considered as juveniles as the number of fins became constant for each part. All the postflexion larvae had detached fins. Additionally, the melanophore was observed to be distributed on the head, centrum of the body, and dorsal fin, and there was a difference in the morphology from the water stream.

• Korean Journal of Ichthyology
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• v.13 no.4
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• pp.223-229
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• 2001

Feeding habits of juvenile Sillago maculata, collected from the tropical seagrass beds in Cockle Bay, Queensland, were studied. S. maculata (0.5~9.5 cm SL) was a carnivore which consumed mainly gammarid amphipods, crabs and copepods. Its diets included small quantities of polychaetes, shrimps, fishes, isopods and cumacean. S. maculata showed ontogenetic changes in feeding habits. Small individuals preyed mainly on copepods, crab larvae and gammarid amphipods. While the portion of the stomach contents attributable to polychaetes, crabs and fishes increased with increasing fish size, consumption of copepods and crab larvae decreased progressively. Gammarid amphipods were the most selected prey item for all size classes.

• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.114-120
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• 1997

Frequencies and the types of abnormal vertebrae in the juvenile of five cyprinid fishes collected from the Kumho River during 1995 and 1996 were examined. Types of vertebral anomalies in investigated species were spinal curvature, fused vertebrae, helical sutures of cetera and abnormal vertebrae with one or two additional spines. The frequencies and the types of vertebral anomalies were different among the species. Of all the examined species, the type with one or two additional spines showed the highest frequencies, 11.72~12.11%. The frequencies of fused vertebrae was 4.45~7.68%. Thes two types of vertebral anomalies were observed in all species. Among the several types of fused vertebrae, the frequencies of double fused vertebrae were higher than those of other types. Also, the incidence of fused vertebrae located in the caudal region of vertebral column was much higher than that in other regions. The percentages of spinal curvature and helical sutures of vertebrae in the investigated species were 0.02~0.15% and 0.02%, respectively. Among the examined specimens, vertebral anomalies include fused vertebrae and one or two additional spines were shown in the three species, Korean slender gudgeon (Squalidus gracilis majimae), False dace (Pseudorasbora parva) and Crucian carp (Carassius auratus). In addition to the two vertebral anomalies, spinal curvature was shown in the Korean gudgeon (Squalidus chankaensis tsuchigae). Dark chub (Zacco temmincki) had fused vertebrae, one or two additional spines, spinal curvature, and helical sutures of vertebrae. This species has the most variable vertebral anomalies. Frequencies of fused vertebrae and one or two additional spines in the all tested fishes were not related with their standard lengths measured. However, spinal curvature and helical sutures of vertebrae were shown only in the specimens smaller than 20mm in standard length.