• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1366-1372
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• 2014

This study was conducted to select the media for the formalin killed vaccine (FKC) production of Vibrio harveyi and its application for olive flounder, Paralichthys olivaceus. For this, we have investigated the immune effects of Vibrio harveyi FKC vaccines grown in 3 different media i.e. Tryptic Soy Broth (TSB), TSB containing 2-2'-dipyridyl (TSB-D), Brain Heart Infusion Broth (BHIB) on the production of agglutinating antibody and protection against Vibrio harveyi in olive flounder. Additionally, a dual vaccine was prepared by combining Streptococcus parauberis vaccine to V. harveyi vaccine and its efficacy was also analyzed with the determination of optimal administration dosage. Consequently, olive flounder immunized with FKC grown in TSB-D showed the same protection with the vaccine grown in BHIB and the optimal dose of the vaccine was 10mg/kg of body weight. Indeed the dual vaccine showed higher agglutination titer and protection than control fish. The optimal dose for dual vaccine was 10mg/kg body weight for each of two vaccines.

• Korean Journal of Environmental Biology
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• v.39 no.3
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• pp.259-265
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• 2021

A diagnostic test for viral hemorrhagic septicemia virus (VHSV), which infects more than 80 species of freshwater and marine fish at home and abroad, causing mass mortality, was conducted to provide quantitative data on the amount of virus expression in various tissues of flounder in chronological order. The tissues were collected in chronological order after the intraperitoneal injection of 3.0E+07 tissue culture infective dose₅₀ (TCID₅₀) per 0.1mL per fish of VHSV to randomly selected flounder. As a result of relative quantification through real-time PCR, the highest levels of virus expression were found in the spleen, kidney, gill, and liver on day 5. This study proved that the spleen was an appropriate site for the final diagnosis of VHSV in the early stages of infection and will provide important information for the diagnosis of legal infectious diseases in Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.332-341
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• 1989

Stomach contents and microstructures in otolith of Chaenogobius laevis were analyzed for the determination of age, growth and food. By comparaing structural similarity in a series of growth increments from three samples collected in a two-week interval, daily deposition of growth increments in otolith can be validated. Growth in length as daily basis was well represented by Gompertz curve: $L= 5.73{\cdot}\;e^{15.06}(1-e^{-0.0015t})$ for the fish age of $46\~102$ days. Mean growth rate increased from 0.40 mm/day for the age of $50\~60$ days to 0.85 mm/day for the age of $80\~100$ days. Chasnobius laevis showed a carnivorous feeding behavior and its major food items were polychaetes, amphipods and copepods. Small individuals ($15\~30$ mm SL) preyed heavily on copepods as well as polychaetes. However, the portion of copepods in stomach contents was decreased with increasing fish siEe, and this decrease was compensated by an increased consumption of amphipods.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.676-681
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• 2002

Different types of transcripts encoding growth hormone (GH) were identified from cDNA libraries constructed with pituitaries of a marine fish species, greenling (Hexagrammos otakii). GH-homologous cDNA clones were isolated using the high-density filter hybridization and the expressed sequence tag techniques. Of 39 full-length positive cDNA clones, 31 clones ($79\%$) displayed an identical sequence, however, remaining 8 clones exhibited several polymorphisms in their sequences including (1) the length and sequence variability in the 5' upstream region, (2) insertional sequences in open reading frame, and (3) deletion and/or single nucleotide polymorphism in the untranslated 3' region. Based on RT-PCT and RNA dot blot analyses, these transcripts were proven to be expressed in a pituitary-specific manner.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.262-266
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• 2016

Marine copepods are ideal live prey for fish larvae, and many studies on the mass culture of the organism have been reported. This study performed a mass culture of the brackish copepod Paracyclopina nana containing nauplius and C4-adult production methods. In nauplius production, the harvested nauplii over 95% were comprised of N1 and N2. Daily mean nauplius production of two trials for 15 days were $6.9{\times}10^6$ and $7.2{\times}10^6$ individuals, respectively. The densities of the adult females were maintained at a similar level of the initiation during production. In C4-adult production, the proportion of harvested copepods containing C4-adult males, females and ovigerus females were 49%, 28%, and 18%, respectively. The daily mean nauplius production of the two trials for 16 days were $8.2{\times}10^5$ and $9.0{\times}10^5$ individuals, respectively. As a result, the continuous production of P. nana using the mass production system was successful. Therefore, the continuous and stable feeding for fish larvae in aquaculture would be possible by the selection of the copepod culture method depending on the mouth size of the fish.

• Development and Reproduction
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• v.10 no.4
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• pp.247-254
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• 2006

It is well publicized that the existence of various endocrine disrupting chemicals threatens normal sexual development of many sedentary marine fishes in the coastal areas. However, a suitable marine fish species for efficient monitoring of this threatening has yet to be identified. One of the difficulties in estimating the effect of endocrine disruption in marine fish is the absence of clear distinction between testicular and ovarian structures at the early stages of sex differentiation. In search of a potential test species, we have investigated the microscopic structures of sexually undifferentiated and differentiated gonads and the susceptibility of gonadal differentiation to exogenous sex steroids during the sex differentiation period in a sedentary marine rockfish, Sebastes schlegeli. Male gonads in this species contained dark pigmentation that made them distinct from female gonads. Treatment either with $estradiol-17\;{\beta}(E_2)$ or $17\;{\alpha}-methyltestosterone$ (MT) significantly altered the sex ratios with the complete sex changes or the occurrence of ovotestis that was easily identified by the mixed structure of dimorphic gonads (coexistence of ovarian cavity/primary oocytes and dark pigmentation/seminiferous tubules). Results in this study suggest that S. schlegeli can be developed as a monitoring/test fish species for endocrine disruption in marine fish in the coastal areas.

• Journal of fish pathology
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• v.26 no.3
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• pp.283-287
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• 2013

The susceptibility of marine medaka, Oryzias dancena to fish pathogenic viruses (infectious pancreatic necrosis virus (IPNV), viral hemorrhagic septicemia virus (VHSV), hirame rhabdovirus (HIRRV), infectious hematopoietic necrosis virus (IHNV), and lymphocystis disease virus (LCDV)) was investigated. The cumulative mortalities of fish immersed with IPNV (experimental condition: $15^{\circ}C$ sea water (SW)), VHSV ($15^{\circ}C$ SW), HIRRV ($15^{\circ}C$ fresh water (FW)) were 30%, 40% and 60%, respectively. In the fish immersed with IPNV ($15^{\circ}C$ FW, $18^{\circ}C$ FW and SW), VHSV ($15^{\circ}C$ FW, $18^{\circ}C$ FW and SW), HIRRV ($15^{\circ}C$ SW), IHNV ($15^{\circ}C$ FW and SW), LCDV ($15^{\circ}C$ FW and SW, $18^{\circ}C$ FW and SW), and mock-challenged group, mortality rate was less than 10%. IPNV, VHSV and HIRRV were re-isolated from the dead fish. These results suggest that marine medaka is susceptible to IPNV, VHSV and HIRRV, although their susceptibility depends on the environmental conditions.

• Journal of Aquaculture
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• v.17 no.3
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• pp.187-196
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• 2004

This study was carried out to investigate changes in biochemical composition of rotifer, Brachionus plicatilis, enriched with the commercial enrichments (Enhance, Advantage, Algamac-2000, DHA-Selco and Advantage ＋ Chlorella) at various durations of enrichment (0, 6, 12 and 24 hr) to improve the growth and survival of marine fish larvae. Total lipid content of rotifers enriched with various enrichments tended to increase with an increase in durations of enrichment up to 6 hr, but after that, was not significantly affected by enrichment materials. However, total protein content of rotifers enriched groups except for Advantage＋Chlorella decreased with the increase in duration of enrichment. The highest protein/lipid ratio showed 2.7 in rotifer enriched with the Advantage ＋Chlorella. The phospholipid/lipid ratio of rotifer enriched with the Enhance, Advantage and Advantage＋Chlorella groups was significantly higher than that of enriched rotifer with the Algamac-2000 and DHA-Selco groups. The highest DHA level, 2.5%, of rotifer enriched for 24 hr was obtained in the Advantage, but was not significantly different among other groups, except for Algamac-2000. No significant difference in DHA level of rotifer enriched with the DHA-Selco, Algamac-2000 and Advantage＋Chlorella groups was observed between l2h and 24hr of enrichment. The DHA/EPA ratio in the enriched rotifers varied among enrichment material groups, ranged from a high level of 11.1：1 in the Advantage＋Chlorella group to a low level of 4.1：1 in DHA-Selco group. The results from this study indicate that rotifers enriched with Enhance, Advantage and Advantage＋Chlorella seemed to be effective to improve nutritional value of rotifer for marine fish larvae because phospholipid, DHAJEPA and protein/lipid ratios of rotifer enriched with Enhance, Advantage＋Chlorella were higher than those of rotifer enriched with either DHA-Selco or Algamac-2000. Especially, supplementation of the Chlorella to these enrichments would appear to be effective for improvement of fish larval performance because of no reduction of protein level in rotifer, which is critical for growth of fish larvae.

• Journal of Life Science
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• v.19 no.9
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• pp.1328-1332
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• 2009

Anisakidosis is caused by anisakid nematodes (family Anisakidae) larvae which can cause not only direct tissue damage but also a severe allergic response related to excretory-secretion products. Lots of different species of anisakid larvae, including Anisakis simplex, Contracaecum, Goezia, Pseudoterranova, and Hysterothylacium, cause the anisakidosis. But it is difficult to diagnosis the species of larvae since the morphologies of larval anisakid nematodes are almost indistinguishable. In order to diagnosis the differential infections of larval anisakid nematodes, polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) of 18S rDNA - was conducted. Three major species of anisakid larvae including A. simplex, C.ontracaecum spp, and Goezia spp. were collected from mackerel (Scomber japonicus), mullet (Mugil cephalus), founder (Paralichthys olivaceus), eel (Astroconger myriaster) and red sea bream (Pagrus major). PCR amplified 18S rDNA from each species of anisakid larvae was digested with eight restriction enzymes including Taq I, Hinf I, Hha I, Alu I, Dde I, Hae III, Sau96 I, and Sau3A I. The original sizes of PCR amplified 18S rDNA were 2.0Kb in both anisakid larvaes and Goezia. Restrction enzymes including Hinf 1, Alu 1, Hha I, Dde 1 and Hae III cut differently and distinguished the A. simplex and Contracaecum type C'. However, Contracaecum type A showed two different restriction enzyme cutting patterns by Taq 1, Hinf I, Alu 1, and Dde 1. One of the patterns was the same as those of A. simplex, Contracaecum type C' and Goezia and the other was unique. These results suggest that PCR-RFLP pattern by Hinf 1, Alu 1, Hae I, Dde 1 and Hae III can be applied to differential diagnosis of human infection with A. simplex and Contracaecum type C'. Contracaecum type A needs further study of classification by morphological characteristics and genetic analysis.

• Journal of Aquaculture
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• v.11 no.4
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• pp.547-556
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• 1998

This study was performed to obtain the basic data on the serum constituents of several marine fish spesies commonly cultured in Korea. Blood samples taken from six species of fish were analyzed for various components of serum, total protein (TP), albumin (ALB), triglyceride (TRIG), cholesterol (CHOL), glucose (GLC), lipase (LIPA), amylase (AMYL), aspartate transaminoferase (AST), sodium (Na), potassium (K), chloride (CI) and phosphorus (PHOS). The fish used were coho salmon (Oncorhynchus kisutch), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), olive flounder (Paralichthys olivaceus), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), olive flounder (Paralichthys olivaceus), parrot fish (Oplegnathus fasciatus) and jack mackerel (Trachurus jaonicus) reared at the Chungmu Experimental Fish Culture Station of KORDI when the water tempetature was ca. 16.5$^{\circ}C$. There were significant differences in TRIG, CHOL, LIPA and AMYZ among the species analyzed. TRIG concentratin were ranged 178~180mg/dl in jack mackeerel and rock fish, 126~159 mg/dl in olive flounder and sea bass, and 102~114 mg/dl in coho salmon and parrot fish, respectively. Jack mackerel showed the highest levels in CHOL (255mg/dl) and GLC(138mg/dl) among species. LIPA levels were recorded 256 U/dl in coho salmon, 41~42 U/dl in parrot fish and rock fisk, and 5~11 U/dl jack mackerel and sea bass, respectively. AMYL activity of coho salmon was measured as 2, 665 U/dl, and that of jack mackerel was 1,210 U/dl while sea bass showed 60 U/dl and parrot fish, olive flounder and rock fish had at most 5 U/dl. On the other hand, there was no significant difference in the concentration of Na and CI. Na and K were proved that they were negatively correlated in all the species. Generally, among blood components, PHOS and CHOL levels were different depending on environmental temperature of each fish species, especially in olive flounder. Rock fish and parrot fish showed high blood concentration of those components during low temperature period while olive flounder and jack mackerel reached high level during their optimal environmental temperature period. The electrolyte concentration and LIPA activity were high during low water temperature period, in general, but TP and ALB concentrations were high during optimal temperature period. The concentrations of TRIG, CHOL and GLC, those which were used as energy sourses, were different among species by season.