• Ocean and Polar Research
• /
• v.27 no.3
• /
• pp.311-322
• /
• 2005

Fisheries buyback programs in Korea have been implemented since 1994, and their scales are estimated to be the present value of 930 billion won for the last 9 yens since 1994. The paper attempts to identify the patterns of each fish species, of which their yields can be steadily increased or significant]y decreased, and to evaluate its effective level and the optimal level for buyback programs by means of fishing capacity analysis. The paper distinguishes fish species, that there is no need to reduce the fishing efforts, such as anchovies, mackerels, squids, Spanish mackerels, and herrings, because MSY exceeds yields, from fish species to control overfishing such as file fish, yellow corvenias, young pollack, hair tail, snow crab, and pollack. The paper also suggests that 65% of the fishing efforts (total tonnages) should be cut back at the national aggregate level in order to restore fish stocks.

• Journal of Aquaculture
• /
• v.10 no.2
• /
• pp.189-197
• /
• 1997

A series of short (8 hours) and long term (96 hours) exposure studies was conducted on a laboratory scale to evaluation (1) the threshold concentrations of petroleum hydrocarbon in seawater which can lead to tainting problems in yellow tail (Seriola quinqueradiata) and (2) the time to recover (depuration period) once the tainting has occurred. The water-soluble fraction (WSF) of crude oil was prepared by stirring the oil with cold seawater. The main component of the WSF were low-boiling aromatics, although these were only al small proportion of the starting oil. From the sencory evaluation it was concluded that the threshold hydrocarbon levels in seawater which will impart a taint in yellow tail fillets within a 8-hour exposure period (short exposure period) are in the range of 0.4 to 1.0 ppm and within a 96-hour exposure period (long exposure period) are in the range of 0.2 to 0.5 ppm. Depuration trials were carried out with WSF from crude oil. The fish were exposed for 48 hours to concentration of 2.5 ppm hydrocarbons. After 48-hour exposure period, the fish were allowed to depurate in fresh, uncontaminated seawater. Depuration time for these fish was 10 days. The taste panelists were able to detect the contaminated fillets very easily while the depurated fish could not be distiguished from the control.

• Journal of Marine Bioscience and Biotechnology
• /
• v.3 no.1
• /
• pp.42-47
• /
• 2008

Sudan is the largest country in Africa with an area of $2,505,810km^2$, of water constitutes $129,810km^2$, and cultivable land is 34%. Sudan has a total land boundary of 7,687 km with 9 border countries. This vast country embraces different vegetation patterns reflecting various climatic zones, grading from tropical rain forests in the south through semi-tropical savannah to arid zone in the extreme north, with annual rainfall ranging from 1,600 mm in the south to 25 mm in the north. The aquaculture industry is not developed as yet. Because of their basic characteristics, the Sudan inland and marine capture fisheries are of a small-scale and semi-industrial nature. The demand for fish and fish preparations is growing steadily. The animal resources sector (which includes fisheries) contributes 21% of Sudan GDP. The contribution of fisheries to Sudanese GDP is currently marginal. The per caput supply is only 1.6 kg/year, which is mostly obtained by capture fish landings. Despite the fact that fisheries GDP is extremely low, fish and fish preparations contribute to the food security of a wide sector of the rural and urban communities. Fisheries also provide work opportunities in the form of secondary employment as a source of income that indirectly contributes to household food security.

• The Journal of Fisheries Business Administration
• /
• v.26 no.2
• /
• pp.133-146
• /
• 1995

WTO system has just begun and the development for fishing industry is being carried out. The task of National Federation of Fisheries Cooperatives(NFFC ) is not only to support producers' competitive edge, but also to realize the efficiency embodied in the businesses of NFFC itself. Then it can continue to compete other firms and offer the comprehensive services only when it achieves its efficiency. The efficiency of NFFC is the economies of scale and scope. NFFC should achieve its scale and scope economies to be efficient. NFFC needs to expand its size in fish distribution and banking business to have scale economies. Also, the communication and coordination systems among member-supporting, fish distribution, and banking business need to be strengthened to get its scope economies. It is interesting theoretically and in policy making to test the hypotheses that cooperatives are capable of offering the comprehensive services such as distribution, credit, and insurance to the members. It is meaningful to their development for agricultural and small businesses cooperatives as well as fisheries cooperatives to survive the fierce competition under WTO system. National Federation of Agricultural Cooperatives(NFAC) is much greater in business size than NFFC. The estimation and test in the multiproduct cost function of NFAC will show interesting results.

• Parasites, Hosts and Diseases
• /
• v.61 no.2
• /
• pp.163-171
• /
• 2023

The present study aimed to determine the infection status of trematode metacercariae and adults in cyprinoid fish from the Khun Thale Swamp in Surat Thani, Southern Thailand, with epidemiologic and faunistic viewpoints. In 2020, 577 fish in 15 species were collected in the summer (February-April) and rainy (September-November) seasons. Fish were individually examined for trematode metacercariae in the whole body and adults in the gastrointestinal tract using a stereomicroscope. Three species of digenetic trematode metacercariae, i.e., Haplorchis taichui, Haplorchoides mehrai, and Centrocestus formosanus, were detected in the muscle, fin, and/or scale of fish. Two species of adult flukes, including Rohdella siamensis and Helostomatis cyprinorum, were collected in the intestines. The prevalence of overall trematode infections was 32.4% (187/577 fish), which was higher in the rainy season (41.4%; 118/285) than in the summer season (23.6%; 69/292). The metacercariae of H. taichui and H. mehrai were detected in 7 fish species each, and those of C. formosanus were found only in Rasbora toneri. The aspidogastrean trematode R. siamensis (adult) was detected in Babonymus gonionotus. A digenean species, H. cyprinorum (adult), was found in Labiobarbus siamensis and Osteochilus vittatus. The present study has first confirmed that the metacercariae of heterophyid flukes, including H. taichui, H. mehrai, and C. formosanus, and adults of R. siamensis (Aspidogastrea) and H. cyprinorum (Digenea) are infected in some species of the cyprinoid fish from the Khun Thale Swamp in Surat Thani, Thailand.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2003.10a
• /
• pp.126-126
• /
• 2003

Performance of a laboratory scale closed seawater recirculating aquaculture system was evaluated. Twenty-kg Korean rockfish (130 fish) with an average body weight of 153.8 g was stocked. Over 107-day culture period, fish reached final density of 51.7 kg/m$^3$ (initial density, 33.3 kg/m$^3$) on the culture tank volume basis. On a daily basis, water addition was 3.4% of the total water volume in the system. Total ammonia nitrogen (TAN)concentrations were below 1 mg/L and nitrite nitrogen (NO$_2$-N) concentrations were within the range of 1-3 mg/L on most sampling days. TAN was removedin bead and sand filters and it was removed or produced in the sedimentation basin. Basically, NO$_2$-N was removed in the bead and sand filters while it was either removed or produced in the sedimentation basin. Nitrate nitrogen (NO$_3$-N) was produced in the bead filters and removed in the sand filter and sedimentation basin. Foam fractionator performed well in the recirculating system. The maximal daily removal values for total suspended solids (TSS) and protein were 10,9 g and 1.4 g, respectively. Whole water quality parameters were within the levels commonly recommendedfor fish culture on most of the sampling days. However, further studies are needed to evaluate the commercial feasibility of this system because of the small-scale system used in present experiment. At least, present study still provides some basic information for further studies of this kind of system.

• Korean Journal of Ecology and Environment
• /
• v.44 no.2
• /
• pp.203-213
• /
• 2011

Agriculture modern environments can vary due to factors such as land consolidation and ditch enhancement projects. But, these improvements projects can include cover-ing-up of irrigation ditches with concrete, increasing the drop between paddy field and drainage ditches, which might decrease the abundance and diversity of fish fauna around paddy fields. In this study, for the management of agrobiodiversity on fish in paddy fields, we installed a small-scale fishways between paddy fields and drainage ditches, and evaluated the effects on the eco-connection of the paddy fields, ditches and stream. Five fish species were recovered at the drainage ditches. The species exhibited characteristics spawning and growth based on the paddy field. The results indicate that the five fish species could ascend the paddy fields through the small-scale fishways. There are no difference of species numbers at ditches of environment-friendly agriculture paddy fields (A) and good agricultural practices (B) region, but individual numbers were higher at the B region. This result could be interpreted as indicating that ditch diversity was affected by positional properties rather than farming practices because the water flow and connection to adjacent stream of B region were better than A region. After ascertaining the fish species capable of ascending in a pre-survey of the drainage ditches, we set up small-scale fishways at the drop between paddy fields and drainage ditches. Three species of fish (Aphyocypris chinensis, Misgurnus anguillicaudatus, M. mizolepis) arrived at the paddy fields via small-scale fishways. The main movement time was from 18:00~24:00 and 00:00~06:00, indicating a preference for the night time period rather than the day period for migration. Concentrating the operation time from night to dawn seems prudent for effective management of small-scale fishways.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.6
• /
• pp.449-455
• /
• 2013

The effect of recycling ratio and fixed media on nitrate and phosphate removal was investigated in a pilot-scale wastewater treatment unit using synthetic wastewater. Addition of fixed media increased nitrate removal from 45 to 58% while no noticeable change was observed for Chemical Oxygen Demand (COD) and phosphate removal (<5%). Nitrate removal efficiency also enhanced (Ca 7%) when the influent wastewater flow was doubled (2Q), however phosphate removal was decreased from 40.9 to 26.6% with the increasing recycling rate. The attached biomass analysis showed the presence of bacteria (73.4 $mg/cm^2$) on the surface of added media in anoxic reactor. Pseudomonas aeruginosa a common denitrifying bacterium dominated the bacterial growth (58%) in the anoxic reactor which was determined using Fluorescence In Situ Hybridization (FISH) analysis.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2003.10a
• /
• pp.125-125
• /
• 2003

Recirculating aquaculture systems consist of different treatment compartments that maintain water quality within the ranges of commonly recommended for fish culture. This paper presents the common considerations in designing different treatment compartments as well as the engineering criteria in designing closed recirculating aquaculture system including a circular tank for fish culture, a sedimentation basin and a foam fractionator for solids removal, two styrofoam bead filters for TAN removal, a sand filter for nitrate removal, and aerators. The main purpose is to outline a common procedure in designing of closed recirculating aquaculture system for marine fish culture.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.508-511
• /
• 2000

In situ hybridization with fluorescent oligonucleotides(FISH) was used to detect and localize microorganisms in the granules of lab-scale upflow anaerobic sludge blanket(UASB) reactors. An UASB reactor was seeded with mesophilically-grown($35^{\circ}\;C$) granular sludge, and thermophilically($55^{\circ}\;C$) operated by feeding with a synthetic wastewater. Sections of the granules were hybridized with 16S rRNA-targeted oligonucleotide probes for Eubacteria, Archaeabacteria, and specific phylogenetic groups of methanogens. FISH clearly showed the layed structure of thermophilic granules, which was consisted of outer bacterial cells and inner archaeal cells. Methanoseata-, Methanosarcina-like cells were also found to be localized inside the granules. These results demonstrated FISH was useful in studying the spatial organizations of methanogens and in situ morphologies and metabolic functions in thermophilic granular sludges.