• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.4
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• pp.307-313
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• 2010

Stanniocalcin 1 (STC1) is a glycoprotein hormone that is important in the maintenance of calcium and phosphate homeostasis in both fish and mammals. STC1 and its paralog STC2 are expressed in multiple tissues in fishes, although the physiological roles of piscine STCs are still unclear compared with those of mammals. In this study, we cloned olive flounder STC1 (ofSTC1) and ofSTC2 cDNAs into pET28a vector and used E. coli Rosetta (DE3) as the host strain for protein expression. Expression experiments were carried out using isopropyl-$\beta$-D-thiogalactoside (IPTG) and nickel affinity chromatography. We could identify the recombinant proteins as single 29.5 kDa (ofSTC1) and 33.2 kDa (ofSTC2) bands in the insoluble fraction on sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE). These results indicate that ofSTC1 and ofSTC2 were expressed as insoluble proteins in E. coli. Furthermore, the injection of ofSTC1 protein into juvenile tilapia resulted in a decrease of the serum calcium level. These results suggest that the purified fish STC1 and STC2 proteins may be used to elucidate the physiological role of STCs in fishes.

• Korean Journal of Ichthyology
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• v.34 no.2
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• pp.86-95
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• 2022

Egg development and morphological change of larvae and juvenile of the Roughscale sole, Clidoderma asperrimum, were investigated in the present study. Adult fishes were collected on the East Sea, Korea, from 2017 to 2018 and reared in a circular water tank (Ø 6×1 m) at water temperature of 12.8±1.9℃. Fertilized eggs ranged from 1.42 to 1.59 mm (mean 1.51±0.04 mm, n=50) in diameter. The eggs were spherical in shape, transparent, floating and colorless. The egg yolk was separated from the egg membrane 60 mins post-fertilization (PF), and an embryo was formed in 62 hrs PF. More than 50% of the eggs hatched within 144 hrs PF in the range of 10.2~11℃(mean 10.8℃). The size of the newly hatched larvae were 4.22~4.64 mm (mean 4.53±0.16 mm) in total length (TL), their mouth and anus were not open yet. At 10 days after hatching, the preflexion larvae reached 5.88~6.62 mm (mean 6.31±0.33 mm) in TL, and the yolk absorption was completed and the mouth began to open. At 55 days after hatching the larvae reached to flexion larvae stage and they were 10.4~13.3 mm (mean 12.7±1.3 mm) in TL, and the tip of notochord was bent upward. At 120 days after hatching the larvae reached to juvenile stage and they were 35.3~40.5 mm (mean 39.5±2.4 mm) in TL. Their all fins had completed set of the fin-rays (D. 79~94: A. 63~75) and the juveniles adopted a benthic life.

• Korean Journal of Ichthyology
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• v.34 no.4
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• pp.244-252
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• 2022

The aim of this study was to investigate the early life history of Squalidus gracilis majimae by observing the development of the eggs and morphology of juvenile fish. Squalidus gracilis majimae used in this study were captured in 2021 June from a tributary flowing into Wicheon, located in Uiseong-gun, Gyeongsangbuk-do. For artificial insemination, ovaprim was injected at 0.5 mL/kg. Egg development occurred 12 h after injection. The size of mature eggs of S. gracilis majimae was 0.80~0.85 mm (0.83±0.01 mm, n=30). Incubation time at 22±1℃ ranged from 62.5 to 69 h. The length of larvae immediately after hatching was 2.39~2.53 mm (2.44±0.04 mm, n=30). On the 18th day after hatching, the larvae had a total length of 8.51~9.84 mm (8.95±0.42 mm, n=30), and the tip of the spine was completely curved. On the 22nd day after hatching, the juvenile fish had a total length of 12.6~13.6 mm (13.0±0.36 mm, n=30), with dorsal fins at iii7 and anal fins at i7. Egg size and hatched larvae size were similar for S. gracilis majimae and S. multimaculatus, and cupulae showed a singularity as it disappeared last among related species.

• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.48-60
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• 1997

The species composition and seasonal variations of fish community in the Zostera marina belt at the coastal water off Hamduck, northern part of Cheju Island, were analyzed based on day and night samples collected by a small beam trawl from May 1993 to May 1994. The dominant species among the 58 fish species in 35 family were tubesnout, Aulichthys japonicus, gobie, Pterogobius zonoleucus, filefish, Rudarius ercodes, pipefish, Syngnathus schlegeli and sea catfish, Plotosus lineatus. These species comprised 86.1% in the number of individuals and 62% in biomass. The number of individuals and biomass were high between October and December, and low between January and April. About 90% of fishes were noncommercial and small-sized fishes, less than 14cm in total length. The larvae and juvenile fishes were collected in the study area throughout the year. The recruitments of dominant species were related to the seasonal variations of Z. marina utilized as a shelter or feeding ground. A japonicus, P. zonoleucus, Zoarchias glaber and Hexagrammos agrammus recruited between January and June, and R. ercodes, S. schlegeli, P. lineatus and Petroscirtes breviceps between July and December.

• Korean Journal of Ichthyology
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• v.4 no.1
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• pp.87-95
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• 1992

Diurnal variation of fish assemblage in the coastal waters, Shinsudo, Samchonpo was investigated using samples collected by RN 80net. A total of 32 species in 24 families was classfied from samples collected during the period of investigation. Enedrias nebulosus, Acanthogobius flavimanus, callionymus sp. dominated in number of individuals. These three most abundant fish species accounted for approximately 55.3% of the total number of fish collected. The percentage similarity values of number were larger than those of biomass. The catches in January and May 1987 showed a significant difference between day and night compositions. The number of species and individuals peaked just after twilight and low tide.

• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.153-158
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• 2015

Five specimens of Lethotremus awae (Cyclopteridae) were collected from the northern coastal waters of Jeju Island, Korea, during a survey on larval and juvenile fishes flocking to aquatic lamp in 2004 ~ 2007. They were characterized by having a spherical body with three barbel-like tubes on head and the first dorsal fin overgrown by skin with undiscernible rays as well as VIII-9 dorsal fin rays, 8 ~ 9 anal fin rays and 22 ~ 23 pectoral fin rays. A new Korean name, "Eom-ji-do-chi", was proposed for the species.

• Journal of Ecology and Environment
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• v.44 no.1
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• pp.54-61
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• 2020

Background: Most fish undergo prey switch from juvenile to adult. It is thought that slightly different feeding habits occur among adult fishes due to growth, spawning, habitat change, and so on. Therefore, the diet of the John Dory Zeus faber (≥ 24 cm TL) was studied in the coastal waters of Korea by analysis of stomach contents, with comparison by season and size class of diet composition and prey diversity. Monthly samples were taken from February 2017 to January 2018. Results: The results showed that the John Dory was a piscivorous predator, and pisces had occupied 82.3% of IRI%. Trichiurus lepturus and Trachurus japonicus were important preys in all size classes and seasons. Diet composition differed among the size classes and seasons (Chi-square test, P < 0.05). As body size of Z. faber increased, the occurrence of benthic fish (Glyptocephalus stelleri) tended to increase. The seasonal prey composition also changed depending on the abundant species of each season. Conclusions: Z. faber is a piscivorous predator. The consumption habits of Z. faber appear to different results by their size and seasons. This study suggests that Z. faber could be considered an opportunistic predator.

• Ocean and Polar Research
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• v.31 no.4
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• pp.305-318
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• 2009

A marine ranching project in Tongyoung was established in 1998, lasting 9 years to 2006. Project activities included the deployment of artificial reefs, the release of young fishes like jacopever and rockfish, and input/output control for specific marine ranching areas in Tongyoung. This report focuses on the economic feasibility of the project in hindsight. Analysis concentrates on three aspects; (a) direct economic benefits, such as increasing effects of fisheries income and savings in harvesting costs, (b) indirect benefits, including increasing effects of recreational fishing and saving R&D costs, and (c) costs, including releasing and purchasing costs of artificial reef and juvenile fish, R&D costs, maintenance costs and harvesting costs. Results show that NPV=4.7 billion won, IRR=8.55% and B/C ratio=1.286 under Scenario 1, which considers the saving effects of R&D costs, and NPV=0.9 billion won, IRR=6.03% and B/C ratio=1.11 under Scenario 2, which does not consider the saving effects of R&D costs, based on 5.5% of the social rate of discount. According to sensitivity analysis, the economic feasibility is very sensitive to the recapture rate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.396-405
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• 2017

We observed the osteological development in larvae and juveniles of Korean spotted sleeper Odontobutis interrupta bred in the laboratory in April 2014. Immediately after hatching, the prelarvae, which were about 4.27 mm long, showed ossification of the premaxillary bones in the upper jaw and the dentary and articular bones in the lower jaw. At 7.11 mm, the larvae showed complete fusion of the post-cleithra and ossification of the scapulae with the appearance of one hole. At 8.65 mm, the larvae showed ossification of seven ribs from the third abdominal vertebra and an increase in the length of the neural spine and hemal spine. The number of caudal fin rays increased to 19. At 11.9 mm, the juveniles showed ossification of three procurrent rays on the side of the parhypural bone as well as ossification of two procurrent rays on the side of the epural bone, indicating the complete ossification of all spicules.

• Development and Reproduction
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• v.18 no.4
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• pp.259-266
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• 2014

The egg development and early life history of Korean spotted sleeper, Odontobutis interrupta which is Korean endemic species from Sora-choen was investigated. The Korean spotted sleeper were caught at Sora-myeon, Yeosu-si, Jeollanamdo, from Korea at May in 2014. The fertilized eggs were $4.23{\pm}0.05mm$ in long diameter and had oil globules. Hatching time of the embryo began about 442 hr 14 min after fertilization under water temperature of $19.5^{\circ}C$. The newly hatched larvae were $4.27{\pm}0.35mm$ in total length and their anus were not yet opened. 3 days after hatching postlarvae was measured $6.20{\pm}0.11mm$ in total length. 10 days after hatching postlarvae was measured $6.69{\pm}0.14mm$ in total length.