• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.59 no.3
• /
• pp.196-205
• /
• 2023

This study investigated the species composition and bycatch status of fishes by fyke net between June and November 2020 in Asanho lake and Chungjuho lake. During the survey period, the catches in Asanho lake were identified as 2,931 individuals of 16 species from a total of six families and in Chungjuho lake were identified as 1,645 individuals of 14 species from a total of eight families. The dominant species in Asanho lake was Erythroculter erythropterus which accounted for 59.6% of the the total number of individuals and 40.5% of the total biomass caught. The dominant species in Chungjuho lake was Lepomis macrochirus which accounted for 48.2% of the the total number of individuals and Erythroculter erythropterus which accounted for 60.2% of the total biomass caught. The bycatch rates of non-commercial species in Asanho lake and Chungjuho lake were 77.0% and 82.6%, respectively. As a result of analyzing the frequency distribution of the total length of Carassius auratus and Siniperca scherzeri, which were the dominant species among commercial species, the bycatch rate of small individuals was 87.1%, and 42.7%, respectively.

• The Journal of Fisheries Business Administration
• /
• v.51 no.2
• /
• pp.15-24
• /
• 2020

As a first step in obtaining the minimum level of data needed to develop smart cultivation technology for Korean seaweed gim (Pyropia yezoensis), farming tests have been carried out using onshore aquaculture facilities. The aquaculture facility was built on paddy farmland on the west coast of Chungnam and received seawater from nearby sea. In this paper, we report the overall process and results of the aquaculture trials attempted in Korea's first onshore gim aquaculture facilities. In addition, the industrial possibility of gim production using the onshore aquaculture system will be discussed through the analysis of all expenses incurred in the test form.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.3
• /
• pp.201-207
• /
• 2008

The seasonal variation and vertical distribution of the marine algal community were investigated using the quadrat method from February 2006 to January 2007 at 10 sites in Gwangyang Bay, Korea. In total, 48 red, 17 brown, and 13 green algal taxa were identified. The algal vertical distribution in the intertidal zone was characterized by Ulva pertusa, while the upper tidal zone was dominated by Gelidium divaricatum. The middle zone was primarily composed of Enteromorpha linza, Sargassum thunbergii, and Chondracanthus intermedia, whereas Hizikia fusiformis, Sargassum thunbergii, Gelidium amansii, and Corallina pilulifera characterized the low tidal zone. Results of cluster analysis indicated that algal composition fell into two groups, which were composed of species in the inland and open sea. In conclusion, the number of species, diversity, and abundance of vegetation in this area were remarkably reduced compared to previous studies in Gwangyang Bay.

• Journal of Aquaculture
• /
• v.12 no.3
• /
• pp.167-173
• /
• 1999

Blocking the 1st mitotic cleavage was performed in mud loach (Misgurmus mizolepis) using UV-irradiated cyprinid loach (M. anguillicaudatus) sperm and ternal shocks Optimum UV range for inactivation of cyprinid loach sperm and thermal shocks. Optimum UV range for inactivation of cyprinid loach sperm was between 3,150 to 4,050 ergs/m$m^2$. Heat shock treatment ($41^{\circ}C$ for 3mins) with various treatment initiation times ranged from 22 to 50 min post insemination resulted wide range of success for induced gynogenesis. Best result was obtained when haploid egges were shocked at 28 min after insemination (corresponding to metaphase division of the 1st cleavage); 26% of total eggs inseminated were viable diploid gynogens. The hatching success and early survival of the both meiotic and mitotic gynogenetic groups were significantly lower than those of control crosses (P<0.05). Maternal origin of induced gynogenetic mud loach was verified by multi-locus DNA fingerprinting.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.4
• /
• pp.1092-1098
• /
• 2015

Fishing population has been increasing with national income improvement and the five-day workweek in Korea. Recently commercial fishing facilities like pay fishing pond are emerging as demand of saltwater fishing increases, unlike the past when inland fishing was prominent. In order to do businesses, economic analysis should be done in advance. This study aimed to make an Economic analysis of Uljin pay-fishing place by estimating the cost and benefit, and calculating the rate of economic return. The results show the Uljin pay-fishing place's net present value of 3.5 billion won, internal rate of return of 14%, and benefit cost ratio of 1.16 at 5.5% social discount rate.

• Animal Systematics, Evolution and Diversity
• /
• v.14 no.2
• /
• pp.67-70
• /
• 1998

A rate species of Ogcocephalid fish, Malthopsis annulifera Tanaka, was recently collected from coastal waters in East Sea, Korea. This species is redescribed as new recod to Korea.

• Korean Journal of Ichthyology
• /
• v.22 no.2
• /
• pp.96-104
• /
• 2010

During an artificial breeding as a part of restoration of the endangered Korean bitterling Acheilognathus signifer, a small number of individuals exhibiting oculocutaneous albinism were produced. We compared the pigmentation and morphology of normal and albinic bitterlings by histological examination of skin samples obtained from 10 regions on the body, fins, and eyes. There were no differences in morphometry and in general morphology of skin between them. In normal bitterlings, pigment cells were better developed in the dorsal region, the upper part of caudal peduncle region, the choroid-retinal epithelium and iris than in other areas. In the albinic bitterling, however, pigment cells were present only in three parts of the dorsal region, the caudal and dorsal fin, which had few melanin cells. Albinic bitterlings also displayed deficient pigmentation in the choroid-retina pigment epithelium and iris. Although they had different pigmentation aspects in distribution and development between normal and albinic bitterlings, melanin cells were mainly present in the dorsal regions of the skin and eyes where are exposed directly to light.

• The Journal of Fisheries Business Administration
• /
• v.5 no.1
• /
• pp.9-42
• /
• 1974

Korea is a peninsular country surrounded by seas on three sides, and the fishing industry has carried out the service of suppling to the people with important anima protein. The distribution of fishery products has very complicated structures, because the production is in charge of small producers scattering along the coast all over the country, while consumpstion is made by separate homes in areas away from producing district. The relation between these two factors the structures make very complicated. The most typical and special structures of fishery distridution are distinguished in two, that is, one is landing market, the other is inland market. Landing markets have been monopolized by fishermen's cooperatives, providing with landing facilities and building sites. Fish markets played not only an important role in the landing, but distribution and price determination of catches by auction or tender. Inland markets are two types of wholesale market in consuming center, one is the terminal market for urban consumers, the other type is the local market for rural consumers. Fundamental functions of landing markets are gathering, assessment, and distribution functions. Gathering function is in charge of wholesaler in fishery cooperative. Gathering amounts are equal to gathering capacity of wholesaler and transact ability of licensed dealers as shown below model. Gathering amount=f.gathering capacity(=pre price.landing facility.account of wholesaler.distance of fishing ground.conveniency purchasing.home port)=fㆍ transact ability of licensed dealers≒f.population or port, and table 1 indicates these relationship. Assessment and distribution functions are in charge of licensed dealers in consumption side. Assessment function should bring the value in production activity through the auction between the cooperative seller and the licensed dealer as buyer. For fair trade transaction in auction, the free competition is supposed to be a prerequisite among the licensed dealers. The ideal condition for free competition is sameness in the scale of buying amount by licensed delaers, but it is almost impossible to attain its goal in actual marketing.

• Development and Reproduction
• /
• v.16 no.4
• /
• pp.321-327
• /
• 2012

Korean bullhead (Pseudobagrus fulvidraco) was collected from the Kum River areas of Kangkyung-eup, Nonsan city, Chungcheongnam-do, Korea, from April to June, 2012 and was fertilized in order to observe egg development and temperature-related cleavage rates and mitotic intervals (${\tau}_0$). The fertilized eggs were separative, demersal and light yellowish with $1.5{\pm}0.06mm$ in diameter, and did not contain oil globules. The first cleavage stages were 90 min, 80 min, 60 min and 50 min at $21^{\circ}C$, $24^{\circ}C$, $27^{\circ}C$ and $30^{\circ}C$, respectively. At higher temperatures, eggs developed faster and underwent further identical development. For Korean bullhead, ${\tau}_0$ were $33.4{\pm}2.08$ min at $21^{\circ}C$, $31.5{\pm}3.06$ min at $24^{\circ}C$, $28.1{\pm}2.11$ min at $27^{\circ}C$ and $26.4{\pm}3.35$ min at $30^{\circ}C$. There were strong negative correlations between the $\tau_0$ and water temperatures at all points studied (Y=-1.13X+58.15, $R^2$=0.98, n=30, where Y is ${\tau}_0$ and X is temperature). The results obtained in this work will be helpful for chromosome manipulation by use of cleavage frequency data and ${\tau}_0$ data in Korean bullhead.

• Korean Journal of Ichthyology
• /
• v.13 no.4
• /
• pp.248-253
• /
• 2001

An histological study was conducted to determine the initial treatment time and treatment duration in the use of sex-reversal hormones in relation to gonadal development and sexual differentiation in the bagrid catfish, Leiocassis ussuriensis. The primordial germ cell, which could be recognized from one-day-old fry, began to protrude into the peritoneal cavity between the mesonephric duct and the gut. The primordial gonad with a genital ridge was developed at 5~10 days after hatching. Sex differentiation of the ovary was identified by the ovarian cavity and meiotic oocytes from 20-day-old larvae. Testicular differentiation was also identified by spermatogonial cells from 20-day-old larvae. It may therefore be concluded that this species belongs to the differentiated type of gonochoristic teleost.