• Environmental Engineering Research
• /
• v.13 no.3
• /
• pp.147-154
• /
• 2008

The purpose of this study was, as a preliminary step for understanding the whole aspects of the impacts of a weir on the ecosystems in upper and lower streams, to find out the impacts of the weirs with and without a fish-way. A survey on the aquatic ecosystem of upper and lower streams of weirs in Ham-an Stream was carried out from June to October, 2006. Results of the investigation showed that some meaningful effects on the ecosystems had occurred by the weirs. The fish fauna in upper stream of the weir with a fish-way appeared to include 3 families, 8 species, and 184 individuals, while that in the lower stream of the weir appeared to include 5 families, 14 species, and 664 individuals. The fish fauna in the upper stream of the weir without a fish-way appeared to include 3 families, 9 species, 107 individuals, while that in the lower stream of the weir appeared to include 9 families, 19 species, 520 individuals, disclosing that, no matter with or without a fish-way, fish fauna species diversity and size of population were more abundant and bigger in the lower stream than in the upper stream, but that difference of fish fauna species diversities between upper and lower streams of the weirs appeared to be bigger for the weir with a fish-way than for the weir without a fish-way. Benthos species diversity and size of population were found to be more abundant and bigger in lower stream than in upper stream, and in wet season than in dry season.

• Journal of the Korean Statistical Society
• /
• v.9 no.2
• /
• pp.213-217
• /
• 1980

This paper aimed at studying an efficient sampling design of the survey for non-consignment fishery products including both marine fisheries and seaculture. An analysis was done on the relationship between precision and sample size. On the basis of the analysis, the sample size was determined to be 1,080 fishery house holds with the expected precision of 4%-5%. The molluscs and seaculture were recognized to be correlated with the non-consignment products. An attempt was made to investigate the coverage of the fish kinds by the sample about 100 fish kinds were found in the 80 selected sample villages, whereas the population includes about 120 in total. This shows that the sample represents the population with satisfaction.

• 한국해양학회지
• /
• v.6 no.2
• /
• pp.104-106
• /
• 1971

In enumerating salmon spawning population by the tag-recovery method, the error caused by the emigration of the tagged fish into the non-statistical area and the misjudgement of the tagged fish as untagged, which is caused by bear predation, appear to give a bias to the estimate of population size. Efforts were made in the present study to remove such bias by estimating population size under certain assumtion and by introducing a correction equation for the sample tag-ratios.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.8 no.1
• /
• pp.1-13
• /
• 1972

Yellow croacker, Tseudociaena manchurica Jordan et Thompson in the Yellow Sea and East China Sea are subjected to be caught by trawl nets throughout the year. First indices of population size in every period 8re calculated. Considering present status of the yellow croacker fishery and ecology of the fish, mathematical models must have been established in order to determine catchability coefficient, natural m ortali ty, fishing mortality, recrui ting coefficient of the fish ing ground, and dispersion coefficienl from the fishing ground. The results an, summmarized as follows: Catchabil i ty coefficient $(C) = 2. 2628 {\times} 10^{-5}$ Natural mortality (M)=0.3293 Population for lhe first half season(July 1st to the following January 3lst) Initial population = 14, 621 $/\frac{M}{T}$ Recruitment =45, 597 $/\frac{M}{T}$ Natural mortality = 8, 660 $/\frac{M}{T}$ Final population =42, 970 $/\frac{M}{T}$ Population for the latter 1131f scason(February 1st to June 30th) Initial population = 69, 170 $/\frac{M}{T}$ Dispersion =51, 688 $/\frac{M}{T}$ Natural mortality = 6, 082 $/\frac{M}{T}$ Final population = 1, 802 $/\frac{M}{T}$.

• Development and Reproduction
• /
• v.22 no.3
• /
• pp.283-288
• /
• 2018

The author carried out PCR-based genetic platform to investigate the hierarchical polar dendrogram of Euclidean genetic distances of one bastard halibut population, particularly for Paralichthys olivaceus, which was further connected with those of the other fish population, by involving with the precisely designed oligonucleotide primer sets. Eight oligonucleotides primers were used generating excessively alterating fragments, ranging in size of DNA bands from larger than approximately 100 bp to less than 2,000 bp. As regards average bandsharing value (BS) results, individuals from Hampyeong population (0.810) displayed lower bandsharing values than did individuals from Wando population (0.877). The genetic distance between individuals approved the existence of close relationship in the cluster II. Relatively, individuals of one bastard halibut population were fairly related to that of the other fish population, as shown in the polar hierarchical dendrogram of Euclidean genetic distances. The points of a noteworthy genetic distance between two P. olivaceus populations demonstrated this PCR procedure is one of the quite a few means for individuals and/or populations biological DNA investigates, for species security and proliferation of bastard halibut individuals in coastal region of the Korea.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.51 no.1
• /
• pp.79-90
• /
• 2018

Fish ages are critical information in fish stock assessments because they are required for age-structure models such as virtual population analysis and stochastic catch-at-age models, whose outputs include recruitment strengths, a spawning stock size (abundance or biomass), and the projection of a fish population size in future. However, most countries other than the developed countries have not identified ages of fish caught by fisheries or surveys in a consistent manner for a long time (e.g.,>20 years). Instead, data about fish body sizes (e.g., lengths) have been well available because of ease of measurement. To infer age compositions of fish in a target group using fish length data, we intended to improve the length frequency analysis (LFA), which Schnute and Fournier had introduced in 1980. Our study was different in two ways from the Schnute and Fournier's method. First we calculated not only point estimates of age compositions but also the uncertainty in those estimates. Second, we modified LFA based on the von Bertalanffy growth model (vB-based model) to allow both individual-to-individual and cohort-to-cohort variability in estimates of parameters in the vB-based model. For illustration, we used data about lengths of Korean mackerel Scomber japonicas caught by purse-seine fisheries from 2000-2016.

• Development and Reproduction
• /
• v.14 no.3
• /
• pp.163-170
• /
• 2010

The gDNA isolated from Korean cuttle fish (Sepia esculenta Hoyle) from Sockcho (SOCKCHO), Seocheon (SEOCHEON), Incheon (INCHEON) and Vietnamese cuttle fish (VIETNAM), were amplified by PCR. Here, the seven selected primers (BION-A07, BION-A09, BION-A11, BION-A20, BION-B04, BION-B06, and BION-B14) were used to generate the unique shared loci to each population and shared loci by the four cuttle fish populations. In this study, the primer BION-A11 detected 112 shared loci by the four populations, major and/or minor fragments of sizes 300 bp, 400 bp, 700 bp and 1,000 bp, respectively, which were identical in all samples. The dendrogram obtained by the seven primers indicates five genetic clusters: cluster 1 (SOCKCHO 01-SOCKCHO 07), cluster 2 (SEOCHEON 08-SEOCHEON 10), cluster 3 (SEOCHEON 11-SEOCHEON 14), cluster 4 (INCHEON 15-INCHEON 21), and cluster 5 (VIETNAM 22-VIETNAM 28). The shortest genetic distance that displayed significant molecular differences was between individuals 25 and 26 from the Vietnamese cuttle fish (0.025), while the longest genetic distance among the twenty-eight cuttle fishes that displayed significant molecular differences was between individuals SOCKCHO no. 02 and SEOCHEON no. 12 (0.640). Individual of Seocheon and Incheon cuttle populations was somewhat closely related to that of Vietnamese cuttle fish population. Even though it could not be affirmed by a single case, such a result seems to be closely connected that the Korean peninsula is subject to climate changes by global warming. In conclusion, our PCR analyses revealed a significant genetic distance among the four cuttle fish populations.

• Journal of Environmental Science International
• /
• v.21 no.11
• /
• pp.1361-1369
• /
• 2012

A biological assessments of fish community structure were carried out in the lower reach of Seomjin River from May 2009 to November 2010. The collected fish from the six surveyed sites were 63 species belonging to 24 families, and 10 orders. Although species was different depending on sites, the numbers of individuals were not shown significance on sites. Locational dominant species were different. For example, the dominant species on May were Zacco platypus at W-1, Zacco temminckii at W-2, Acanthogobius flavimanus at W-3 and W-4, and Leiognathus nuchalis at W-5 and W-6. There is no seasonal differences in species. Species diversity was the best up to 2.64 on May at W-1 from 1.33 on November at W-6. As a result of an analysis about environmental factors for the numbers of fish species and individuals in each surveyed sites, the most effective groups were DO, BOD, and COD. The proportional difference was high on May than November between transient and asymptotic projections for population size and population growth rate for simulations starting at the current or theoretical stage distribution.

• Animal cells and systems
• /
• v.4 no.4
• /
• pp.341-345
• /
• 2000

It has been very difficult to develop and evaluate efficient fish vaccines because fish immune cells have not been properly characterized. In this study, we investigated the cell-mediated immunological properties of B- and T-like cells in Nile tilapia (Oreochromis nilotica). Surface immunoglobulin negative ($slg^{-}$) cell population proliferated in response to mammalian T-cell mitogens PHA and Con A, while surface immunoglobulin positive ($slg^{+}$) cells responded to the B-cell mitogen LPS. The slg$^{[-10]}$ cells from hemocyanin (HC)-immunized Tilapia, compared to the non-immunized control, reacted more to PHA than to Con A. Unexpectedly, antigen (Ag)-specific response was observed in both $slg^{-}$ and $slg^{-}$cells. Regardless of HC immunization, whole leukocytes from 8 head kidney of fish showed natural killer (NK)cell activity. Especially, NK cell activity was much higher in slg$^{[-10]}$ cells than in slg$^{+}$cells, indicating the possibility that fish NK cells were not at least associated with slg$^{+}$ cell population and not activated by Ag. Further understanding of functional fish immune cells will help to evaluate and develop effective vaccines for fishes and to monitor the course of therapy In infected fishes.hes.

• Fisheries and Aquatic Sciences
• /
• v.27 no.3
• /
• pp.159-170
• /
• 2024

Research to obtain molecular markers related to the major histocompatibility complex (MHC) gene in both strains of gourami is essential to increase the success of the selection program of disease resistance traits. Using a completely randomized design (CRD), the challenge test consists of four treatments and seven replications. The treatment was Jambi gourami injected with PBS (KJ), Kalimantan gourami injected with PBS (KK), Jambi strain injected with Aeromonas hydrophila (GJ), and Kalimantan strain injected with A. hydrophila (GK). The GJ population was more resistant to A. hydrophila than the GK population. The MHC II gene was detected in both test strains (GJ and GK), both resistant and susceptible fish. However, there were differences in the results of amplifying the MHC II gene in susceptible and resistant fish. Two DNA fragments approximately 400 and 585 bp were detected in the genome of susceptible fish, while in the genome of susceptible fish, only one DNA fragment was detected (400 bp). Therefore, the MHC II gene fragment with a size of about 585 bp can be used as a potential candidate for specific molecular markers to obtain resistance to A. hydrophila bacteria in the giant gourami.