• KOREAN POULTRY JOURNAL
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• v.40 no.5 s.463
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• pp.96-101
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• 2008

2003/04년에 국내 첫 발생한 고병원성 조류인플루엔자(이하 HPAI)가 2006/07년에 재 발생되었고, 금년 4월 들어 3번째로 발생하면서 농가는 물론, 국민들의 불안감은 더욱 고조되고 있다. 올해 발생 상황에 따르면 4월 1일 전북 김제시 산란계 농장을 기점으로 20일 사이에 50여 농가에서 신고가 접수되었고, HPAI가 19차례(08.04.23현재) 발생했다. 첫 발생일로부터 2주 뒤엔 최초 발생농장에서 200km 떨어진 경기도 평택에서도 발생되면서 지난 15일 전남북도에 한해 실시하던‘경계’단계의 위기 경보를 전국으로 확대한 바 있다. 특히나 예년과는 다르게 겨울철이 지난 4월에 첫 발생된 점과 전북 김제의 한 농장에서 방역초소를 뚫고 구입한 오리를 전남북 및 충청도 일대 음식점으로 납품하는 등 예기치 못한 상황이 발생하면서 AI가 급속히 확산될 가능성이 커지는 가운데 가금업계가 큰 위기에 직면하게 되었다. 본고는 금년에 발생된 HPAI 발생 현황에 대해 정리해보았다.

• Journal of Aquaculture
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• v.8 no.3
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• pp.195-207
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• 1995

In order to study the embryonic development and hatching of wild long shanny, Stichaeus grigorjewi, were caught with the gill nets in the East Sea of Korea, and stocked at indoor tanks to induce natural spawning in February 25, 1994 and February 16 to 24, 1995. They were already matured when stocked, and average body length (50.66 cm) and body weight (1,192.74 g) of 57 females and average body length (48.62 cm) and body weight (612.58g) of 43 males were recorded. Before stocking, they were inserted with identification tags(ID tags) in the dorsal muscle, and spawning was traced by the portable reader (Destron/lDl Ltd.) Forty females among 57 spawned successfully in the average of 4 days after stocking. Females spawned almost all eggs contained in the ovaries at one time in the form of an egg mass and averaging 227,200 eggs Per egg mass. The egg mass was oval in shape, translucent milky in color, 20.32cm long axis and 14.57cm short axis in size, and 803.7g in weight. Male parents guarded their egg masses and circulated water with the tail part of the body. Fertilized egg was spherical in shape, and their average diameter was 1.54 mm. Each egg had a containing single oil globule, and it's average diameter was 0.37 mm. The average water temperature was $13.2^{\circ}C$ and incubation times after fertilization were 5 hours 25 minutes up to 2-cell stage, 13 hours up to morula stage, and 66 hours 35 minutes up to embryo formation stage. Hatching rate was approximately 10 percent in 368 hours 50 minutes after fertilization, and approxionateoly 90 percent of eggs were hatched in 425 hours 30 minutes after fertilization.

• 한국해양학회지
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• v.30 no.5
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• pp.403-412
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• 1995

The present study was performed to determine th growth and production of Mactra veneriformis on the Songdo tidal flat off Inchon. west coast of Korea. Monthly samples were collected from Marc 1989 to September 1990. The size distributions of shell length showed unimodal patterns from March to August 1989. The binodal pattern after September 1989 indicated a recruitment of young clams during this period. The density fluctuated irregularly, but showed a decreasing pattern over time on the whole. The density of the year class 1989 increased markedly after February 1990. The growth in shell length showed three phases during a year, a fast growth phase in spring, a slow growth phase in summer and autumn, and a lag phase in winter. The annual increment in shell length reduced with age. The flesh dry weight showed a peak in late spring just before the spawning period, and another peak in autumn. The length of annuli and the back-calculated flesh dry weight were used to describe the annual growth. The growth in shell length fitted to the von Bertalanffy model and the flesh dry weight to the Gompertz model. The absolute growth rate of the shell length reduced gradually with age. The year class 1985 had the highest L, and the yeat class 1986 the lowest L. The annual growth in weight showed a typical sigmoid curve. The growth rate was maximum at the age of 2 to 3. Year classes of 1984 and 1985 had higher values of W and higher absolute growth rates than those of 1986 and 1987. Maximum absolute growth rates of 1986 and 1987 year classes were recorded at younger ages than 1984 and 1985 year classes. The annual relative growth rates of length and weight decreased exponentially with age. Biomass in flesh dry weight increased till spring and thereafter decreased progressively. Maximum biomass was 134.6g m/SUP -2/ in August 1990. The biomass of 1989 yeat class occupied highest proportion in total biomass. Annual production in flesh dry weight from March 1989 to March 1990 was 67.9 g m/SUP -2/ year/SUP -1/. Cumulative production of 1989 year class was highest among all year classes, and that of year class 1984 was lowest. The production is high in spring and autumn, and very low in summer and winter.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.274-281
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• 2020

This study aimed to investigate the autumn spawning by bitterling (A. rhombeus) inside mussel (Unio douglasiae) and the adaptation characteristics at the Bongseocheon Stream of Mankyeonggang River. The survey was carried out between August 2015 and July 2016. The spawning season was from September to November, and 17-75 (36.2 ± 16.44) eggs were found from mature females. During the survey period, 476 mussels were collected, 129 (27.1%) of spawned A. rhombeus. Mussels that spawned eggs, embryos, and larva of A. rhombeus (46.3 ± 4.55 mm, n = 129) were larger than than those that did not spawn (42.6 ± 8.51 mm, n = 347). The appearance frequency of A. rhombeus larva before and after the formation of lens was 99.8% (n = 597) vs. 0.2% (n = 1) from October 2015 to March 2016, 25.6% (n = 23) vs. 74.4% (n = 67) in April 2016, 0% (n = 0) vs. 100% (n = 40) on May 2016. The number of eggs, embryos, and larvae of A. rhombeus inside the mussels were 1-18 (5.6 ± 3.81). The number and appearance frequency of A. rhombeus eggs, embryos, and larvae inside the mussel according to mussel gill demibranchs position were 1 (0.01 ± 0.09, n = 1) and 0.78% in the left outer demibranch, 1-18 (2.33 ± 3.31, n = 63) and 48.84% in the left inner demibranch, 1-15 (2.97 ± 3.79, n = 76) and 58.91% in the right inner demibransh, and 1-12 (0.33 ± 1.71, n = 7) and 5.43% in the right outer demibransh. The highest frequency of the developmental position of eggs, embryos, and larvae occurred 71.8% (n = 445) in lower part 3 (L3) before formation lens and 94.4% (n = 102) in L3 after formation lens, indicating that L3 was dominating position for eggs, embryos, and larvae. More eggs, embryos, and larvae of A. rhombeus were found more often in the inner demibranshs than outer demibranchs. Since A. rhombeus is a species that spawn in the autumn and thus avoids the competition with interspecific and glochidia. However, they have to spend the winter in low water temperature. Consequently, we assume that A. rhombeus have evolved toward embryonic diapause under the low water temperature before the formation of lens and spawning inside the supracranchial cavity to save the transit energy from the water space to the suprabranchial cavity after the achieving movement ability with the formation of lens.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.140-149
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• 2018

Seasonal variations in the community structure of larval fish assemblage in Jinhae Bay were investigated in February, May, August and November of 2015, and in the same months in 2016. During the study period, a total of 28 larvae species belonging to 24 families were collected. The dominant species were Clupea pallasii, Liparis tanakae, Callionymidae sp., Sillago japonica, Ernogrammus hexagrammus and Engraulis japonica. These six species accounted for 77.6% of the total number of larvae during the survey period. The larvae of C. pallasii and L. tanakae were exclusively caught in February 2015 and 2016, while those of Apogon lineatus and Sillago japonica were exclusively caught in August 2015 and 2016. Overall, species diversity of the fish larvae was highest in February and August, although it was relatively low in May. The results of the non-metric multidimensional scaling (nMDS) analysis using the number of individual larval fish showed that they are divided into four seasonal groups. Our results showed that the community of larval fish in Jinhae Bay was affected by seasonal changes in temperature and the emergence of spawning fish species. Additionally, we suggest that the high abundance of larval fish came from around Jam-do and the northern part of Chilcheon-do; these locations are the main spawning grounds of Jinhae Bay.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.154-161
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• 2010

The reproductive ecology of the cardinalfish Apogon lineatus was examined using 4,300 specimens collected monthly from January to December 2006 in the coastal waters of Gori, Korea. Specimens ranged in standard length (SL) from 2.1 to 8.6 cm. They were distributed more in surface areas during summer and autumn and more on bottom areas during spring and winter. The gonadosomatic index (GSI) of females was highest in September and decreased until December, with the spawning season lasting from August to October. The monthly ratio of female to male did not significantly differ (${\chi}^2$-test, p>0.05). The size of 50% maturity was estimated at 5.43 cm SL and all females more than 7.0 cm SL were sexually mature. A. lineatus is a multiple spawner, spawning on more than one occasion in a single spawning season. The maximum egg diameter was 0.65 mm. Fecundity (F) ranged from 8,555 to 20,084 eggs, with a mean of 15,038 eggs. The relationship between fecundity and standard length was estimated as F=$334,851\;SL^{1.9876}$ ($R^2$=0.53). The relationship between fecundity and body weight(BW) was estimated as F=7,167.6 Ln (BW)-2,198.1 ($R^2$=0.33).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.164-179
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• 2001

Spatio-temporal variation in species composition, abundance and distribution of fisheries resources caught by large purse seine off Korea from 1991 to 1994 was analysed. Out of 19 species, Scomber japonicus (54.7%), Sardinops melanostictus (20.4%), Trachurus japonicus (9.1%), and Scomberomorus niphonius (6.2%) were predominated in catch. These 4 pelagic fishes occupied 90% of total catch. Major pelagic fishes caught by large purse seine were dispersed to northward from spring to summer, and migrated to the southern wintering ground during winter. Fishing effort (number of haul) was high in summer, but catch per unit effort showed a peak in winter. The high CPUE in winter seemed to be related to aggregation of the pelagic fish to the wintering ground in the southern sea. After spawning, they were widely dispersed for feeding in warm months.

• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.845-853
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• 2019

The aim of this study is to investigate the factors affecting the habitat characteristics of largemouth bass (Micropterus salmoides), which is one of exotic fishes in Korea. Based on field observation, the laboratory experiments were performed in order to investigate the relationship between water temperature and the habitat characteristics of largemouth bass. It was found that largemouth bass preferred a relatively high water temperature in winter and a low temperature in summer. When the small largemouth bass coexisted with large largemouth bass, the separation of habitats depending on the size of each largemouth bass are observed. In the separated habitat areas, it is also observed that the largemouth bass preferred vicinity of the obstacle such as boulder. From the experiments for preference between water temperature and obstacle, it was observed that a primary consideration in habitat selection was obstacles. It was also observed that when light device was turned on, largemouth bass formed a new habitat.

• Journal of Aquaculture
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• v.9 no.1
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• pp.65-71
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• 1996

To estimate the variation of food organisms on the corrugated PVC sheets, we analysed the chlorophyll a and. pheopigments of the benthic microalgae on the sheets from the oyster culture ponds. We estimated the standing crops as the amounts of chlorophyll a, and the physiological state of cells as the pheopigments level in the benthic microalgae. The amount of chlorophyll a was increased by immersion time in winter but the peak was observed every two weeks in summer, while the ratio of pheopigments was highest in summer but the low level was observed in spring and autumn. These seasonal variation were well coincided with the natural spawning season and the good microalgae nutritional valance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.68-80
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• 1984

Garolim Bay is not only important fishing ground but also expected area for the tidal power plant. The construction and operation of tidal power plant will make change the ecosystem of this bay. Therefore, the actual fisheries stocks should be precisely understood for the effect estimation and overall utilization of the bay after the construction of the tidal power plant. During the study period from January through December in 1981, forty-six adult fishes species, 3 species of fish egg and 25 fishes larvae species have occurred in the bay. Considering the result on monthly distribution of eggs and larvae, the inner area of the bay seems to be important as nursing ground of larvae spawned at the outside bay in winter, e. g., Ammodytes personatus, and Enedrias sp. This inner bay is also major spawning ground for many species spawning in spring and summer, e. g., Gobiidae, Konosirus punctatus, Engraulis japonica, etc. Taking into consideration the annual mean production for three years($1978{\sim}1980$), there are two major fishing seasons. The one is in May-June for Enedrias larvae stock, and the another in October-November for big eyed herring stock. For the mariculture stocks, short necked clam, oyster and laver are important species. After construction of the tidal power plant, the migratory species, i. e., larvae of Enedrias and Ammodytes personatus, Mugil cephalus, Konosirus punctatus, etc. will be directly damaged by the interuption of migration route. On the otter hand, the change of physico-chemical factors of seawater will also affect the ecosystem of the bay. Consequently, for the overall utilization of the bay after construction, the actual ecosystem including the fisheries stocks, must bs precisely revealed, and the mechanical designs, e. g., sluice position and its demension, should be also considered with these biological characters of the bay.