• Korean Journal of Poultry Science
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• v.10 no.1
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• pp.1-22
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• 1983

The Purpose of this study is to examine both supply and demand side of broiler chicken in Korea. Especially the paper aims to investigate the broiler chicken production Dressing and marketing pattern which may affect the demand for it. It is generally understood that broiler chicken production becomes unstable because of frequent market price fluctuation mainly due to disequilibrium of quantities demanded ana supplied It is important to point out that marketing in the form dressed chicken has been enforced by the regulation in Seoul area since March 1st, 1983, though live birds have been customarily marketed for year. It is assumed that the subsituation of chicken meat for beef would save foreign exchanges, because increasingly large amount of beef is imported mainly thanked to a chronical shortage in local production. Main findings of this study may be summarized as follows: 1) Broiler chicker production has been rapidly increased recently, estimating 180-200 million head per year with the trend of contineous increase year after year. Price fluctuation during the year is found, especially summer and winter mainly due to seasonal demand change. It is known that mal-funconing of broiler chicken market may be one of the causes for a large Price fluctuation. Accordingly the increase of marketing efficiency may reduce the price fluctuation and also positively impact on creating demand for the chicken consumption. 2) It is also interesting to note that 90 percent of broilers are grown on the floor and almost 86 percent of total broilers composed of so called high-bros, weighing on an average more than 1.6kg per head Approximately 8 weeks are required for of around marketing birds at the feed efficiency of around 2.3-2.5 Average broiler farm raises between 1,000 and 2,000 head, showing a quite small scale of operation. Only a few sampled farmers follow an all-in and all-out method in broiler production.

• Journal of Forest and Environmental Science
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• v.14 no.1
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• pp.128-137
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• 1998

In Fukuoka, the natural enemies of Protopulvinaria mangiferae were confirmed as six primary parasitoids, three hyperparasitoids, and six predators. Among the primary parasitoids, Aneristus ceroplastae, Microterys flavus, and Coccophagus yoshidae were relatively abundant in Fukuoka. Aneristus ceroplastae and Coccophagus yoshidae were solitary endoparasitoid, whereas Microterys flavus was a gregarious endoparasitoid. Tetrastichus sp. was a hyperparasitoid and solitarily ectoparasitic to the pupae of Aneristus ceroplastae and Microterys flavus. The seasonal fluctuation of parasitisim and adult emergence of the important parasitoids was investigated in Fukuoka. Among the predatorys, Rhyzobius forestieri and Chilocorus kuwanae were relatively abundant, and seasonal fluctuation of adult emergence and consumption of the host were studied. As the first record from Japan, Rhyzobius forestieri was collected on leaves of Elaeocarpus sylvestris with heavy infestation of Protopulvinaria mangiferae.

• Korean Journal of Environmental Biology
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• v.20 no.1
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• pp.46-54
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• 2002

We observed zooplankton community to understand variations in the species composition and abundance in Gangjin Bay. Samples were collected bimonthly from February to November 1999 at 10 stations in Gangjin Bay of the southern part of Korea. Zooplankton communities consisted to nine taxa and mean biomass was 2,028 indiv. $m^{-3}$. The maximum abundance was observed to be 5,496 indiv. $m^{-3}$ in February and the minimum in November, 78 indiv. $m^{-3}$. Copepods dominated and most diverse in Gangjin Bay. Seasonal fluctuation in the copepod abundance varied between 42 and 4,159 indiv. $m^{-3}$. Dominant species are Acartia omorii, Centrophages abdominalis, Paracalanus indicus and A. steueri. Cladoceran also dominated and the maximum abundance was 765 indiv. $m^{-3}$ in April. A. omorii and Oithona davisae dominated in February, A. omorii, Eurytemora pacifica, Evadne nordmanni and Podon polyphemoides in April, Tortanus dextrilobatus and decapod nauplius in June, Paracalanus indicus, E. tergestina and Penitia avirostris in August and A. erythraea and P. indicus in October. In November, P. indicus and Sagitta crassa dominated.

• Journal of Veterinary Clinics
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• v.19 no.1
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• pp.14-18
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• 2002

An epidemiological study was performed to evaluate the state of fish diseases between aquaculture fishes in the area of southern Kyeongnam, especially Tongyeong-si, Geoje-si, and Goseong-gun. Examination for a total of 91 cases was carried out for a variety of fishes, including Japanese flounder(Paralichthys olivaceus), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), sea breams(Pagrus major), and red drum (Sciaenops ocellatus) from November, 1999 to October, 2001. The investigation resulted in exploring 155 infectious diseases, including 62 Vibriosis, 16 Edwasiella infection, 11 Streptococcosis, 7 Pseudotuberculosis, 15 Scuticociliatida infection, 20 Gill flukes, and 9 Trichodiniasis. When the infections were classified according to fish species, Japanese flounder was infected by 30 Vibrio spp., 16 Edwardsiella tarda, 6 Streptococcus spp., 12 Scuticociliatida infection. In case of sea bass, 10 Vibrio spp. was able to isolate out of 10 outbreaks, on the other hand, rock fish was dominantly infected by gill flukes since it was observed 12 out of a total of 20 cases. With reference to seasonal fluctuation, Vibrio spp. infection was continually observed through all seasons but Edwardsiella septicaemia, Streptococcosis and Pseudotuberculosis was mainly isolated in summer and autumn when the water temperature was raised high. Scuticociliatida infection was frequently occurred from late autumn to early spring but gill flukes were watched all the year regardless of temperature. As regards, multiple infection, 47 out of 91 cases was Identified to have involved in more than 2 pathogens, especially Vibrio spp. was highly mixed with other pathogens since 42 out of 47 cases was mixed with Vibrio spp.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.5
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• pp.438-445
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• 1993

Spatial and seasonal variations of community structure of demersal fishes in Asan Bay were studied using seasonal samples collected by an otter trawl from autumn 1991 to summer 1992. For each sampling station, three trawl hauls were completed to obtain a reliable sample. Of 34 species identified, Cynoglossus joyneri, Johnius belengeri, Zoraces gillii and Thrissa koreana accounted for $93\%$ of the individuals collected. The former three dominant species were more abundant on the finer sediment of the inner bay than on the sandy bottom of the outer bay. Spatial variation of community structure of demersal fishes was analysed by principal component analysis using rank correlation. The community structure did not show a spatial difference, but a clear seasonal trend. This distribution pattern seems to be related significantly to the seasonal temperature fluctuation and to the active mixing of the water by strong tidal current of the bay.

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.91-96
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• 2020

Seasonal fluctuation in abundance and species composition of fish in coastal waters off Nang island were investigated using seasonal samples collected by long-bag stow net in 2017. A total 10,208 fish were sampled and classified into 37 species, 26 families, and 9 orders. The dominant species were Engraulis japonicus (4,886 individuals, 47.9%), Pennahia argentata (842 individuals, 8.2%), and Ilisha elongata (369 individuals, 3.6%). The diversity index was the highest in May (H'=3.23) and the lowest in November (H'=1.24). The dominance index was the highest in November (D=78.7%) and the lowest in May (D=22.4%).

• Korean Journal of Remote Sensing
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• v.28 no.3
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• pp.267-276
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• 2012

Terminal lakes are widely distributed in the arid and semi-arid Gobi of Mongolia, and serves as important water resource for local people and livestock. However, such lakes are subject to great fluctuations in its size depending on climatic conditions and human water utilization. The Orog Lake is one such example that has shown remarkable fluctuation in recent years. In this study, we investigated the temporal changes of Orog Lake surface area by using 16-day MODIS 250 m NDVI products from 2000 to 2010. The results were compared with climate variability represented by monthly precipitation and temperature. Our results show that the Orog Lake gradually shrank for the period from 2000 to 2010, but with a significant range of seasonal and inter-annual variability. The lake area showed considerable seasonal variations, as it expanded in spring and fall, primarily due to snow melt and summer precipitation, respectively. Extreme drought period from 2000 to 2002 triggered the substantial reduction in lake area, leading to dry-up in year 2005, 2006, 2007, and 2009. After dry-up once occurred in 2005, the lake repeated reappearance and disappearance depending on seasonal and annual precipitation. Our findings implicate that the ground water fluctuated around the lake bottom level since 2005. This suggests the highly vulnerable nature of Orog lake, which greatly depends on future precipitation change.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1417-1430
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• 2015

In this study we were to explore the seasonal variation of water temperature distributions before and after weir construction at Gumi, Chilgok, Gangjung(Goryung), Dalsung in the Nakdong River using Landsat satellite images. Relationship between in-situ water temperature and radiance values of Landsat-5, 7, 8 satellite images showed high correlation. Seasonal variation of water temperature in Nakdong River showed that the fluctuation ranges of water temperature before weir construction were larger than those after weir construction. This indicated that the variation of water temperature is due to the difference of heat storage volume by weir construction and dredging work. In particular, the water temperature after weirs construction in autumn was 4-8 times lower than that before weirs construction. Water temperature after weir construction decreased in spring and summer at the downstream of Gumi weir and Gangjung(Goryung) weir, and the upstream of Dalsung weir. In autumn and winter, the water temperature after weir construction increased in the upstream and downstream of the whole weirs except upstream of Gumi weir. Relationship between water temperature and meteorological elements (air temperature, wind speed, sunshine, radiation) showed high correlation of above 94% in air temperature, and then radiation was high correlation before and after 65%.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.2
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• pp.178-195
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• 1999

The species composition and seasonal variation in abundance of fishes in the Nakdong River estuary were investigated monthly from February 1987 to January 1988. During the study period, 23,008 specimens belonging to 100 species were collected. The most abundant fish species were Repomucenus valenciennei, Pholis fangi, Leiognathus nuchalis, Trachurus japonicus, and Sardinella zunasi. These five species comprised 63.0% of total fishes and 47.8% of total biomass collected. The seasonal dominant fish species were P. fangi and R. valenciennei in spring, R. valenciennei and Cynoglossus joyneri in summer, Thryssa kammalensis and Apogon lineatus in fall, and R. valenciennei, L. nuchalis and S. zunasi in winter. The number of fish species, number of individuals collected, and species diversity indices fluctuated with the seasons. The number of species and number of individuals decreased significantly in the upper estuary. While temperature was an important factor which influenced on seasonal fluctuation of the fish community, salinity determined the spatial distribution of fishes.

• Health Policy and Management
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• v.23 no.3
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• pp.260-265
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• 2013

Background: The aim of this study was to examine the seasonal variation of death from intentional self-harm by hanging, strangulation and suffocation (HSS: Korean Standard Classification of Diseases-6 code: X70) using the 2011 death registry data. Methods: The analysis was based on data of 8,359 HSS deaths from 2011 national vital statistics in Korea. Daily, weekly, and monthly death pattern on HSS were used to examine the relationship seasonal variation and HSS deaths. Results: A total of 8,359 HSS deaths occurred in 2011, with a mean age of 50.6 years. The HSS death rate (per 100,000) was 25.5 in male and 10.8 in female. In one day 17.6 males and 8.0 females occurred HSS death on average. The number of HSS death per day was the highest on 8th June (45 deaths), and lowest on 1st February (7 deaths) during the period. The variations of daily HSS death showed wide fluctuation from a peak of 34 to 45 deaths (29th May to 9th June) to a trough of 17-26 deaths (10th-13th September: the Korean thank-giving consecutive holidays), 13-20 deaths (2nd-5th February: the new year's day by the lunar calendar) and 8-9 deaths (24th-25th December: Christmas holidays). There were no significant difference between gender and seasonal variation (month, season, and week). Conclusion: The mean number of HSS death per day was highest in June (30.6 deaths), and months with the lowest number of deaths was January and December (range, 19.4 to 19.6 deaths). HSS death were more prevalent during summer and spring and were less likely to occur during winter. On Saturdays (21.0 deaths), the number of HSS death per day was the lowest, and Monday (27.9 deaths) was the highest. HSS death was less likely to occur on holidays (21.4 deaths). There was significant seasonal variation in HSS death by weekly and monthly (p<0.01).