• Journal of fish pathology
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• v.3 no.1
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• pp.21-25
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• 1990

In inland aquaculture, a lot of fishes often died cause of touch of L. carteri which is attached on the net cage. In this works, the experiment were carried out on classification of species, toxin test, and extermination with some chemicals. A bryozoa from net cage in lake Okjeong is classified into the Phylactolaemata, Lophopodella carteri Hyatt. A bryozoa broke out firstly on the 30th of June with water temperature up to $31^{\circ}C$ and it reattached on the net with water temperature below $30^{\circ}C$. Size of bryozoa colony is about $0.8{\times}0.6{\sim}1.7{\times}1.5cm$. Water column of attachment was 0~5m and the peak is 2~3m. In toxin test on the israeli carp, goldfish and catfish touched with bryozoa for 1 minute at $25^{\circ}C$ of water temperature, a dead fish appeared at 20 minutes after touched. Mortality was 90% for israeli carp and 100% for goldfish at 100 minuties after touched, but catfish was not died at all. It was supposed that the toxin is from nematocyst being around tentacles and this toxin act a deadly poison on a israeli carp and goldfish. In extermination test, the bryozoa treated with 300ppm of formalin, 5% of sodium chloride, 5ppm of malachite green, 200ppm of potassium permanganate, 1000ppm of potassium iodide, 10ppm of DDVP for minute respectively, all of them were not effected.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.151-156
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• 1984

The Chili fish, one of the most common species of the freshwater fishes, is distributed in the river basins of the western coast of Korea. However, any studies on this fish, especially its development or life history, have not been made so far. The authors, therefore, carried out an experiment to reveal some characteristics of egg develoment and fry in this fish. For accomplshing this study, we caught some adult Chili fish by means of a casting net at raceway in the vicinity of Kunsan in June and July, 1983; then, we injected 0. 1 cc Gonadotrophic hormone 1,000 unit solution (Puberogen) in order to induce the spawning on the abdominal cavity of male and female respectively, Approximately 12 hours after injection, the artificially fertilized eggs by using of the dry method and the naturally fertilized eggs were observed simultaneously in the aquarium ($30{\times}50{\times}70cm$). The fertilized eggs, in spherical shape, were sperative, demersel, adhesive nature and $1.38{\sim}1.59\;mm$ in diameter. The light yellow yolk was opaque and $1.17{\sim}l.27\;mm$ in diameter. The hatching of eggs took place at 29.5 hours after fertilization under the condition of $23.5{\sim}25.0^{\circ}C$ water temperature. Basically there were not found so many different aspects in comparison with the common species of Cyprinidae in the development process of eggs : however, there were a few noticable characteristics, that is, pigment cells, eye balls and blood circulation are invisible, or the velocity of egg development is rapid, seemed similar to the Loach's egg. Newly hatched larvae with the yolk sac (2.39 mm in size) were $3.87{\sim}3.99\;mm$ in total length and their myotome number was expressed as 28+15=43. About 20 hours after hatching, a caudal and a pectoral fin as well as an anus began to orgin. In addition, a few malanophore showed on the upper regin of the yolk sac of the larvae whose size was 4.73 mm in total length. The larvae developed about 5.02 mm in total length, and the median fin fold in the abdomen extended forward to two thirds or beyond of the yolk sac at 50 hours after hatching. Simultaneously, the eye balls and mouth also appeared. After 3 days, the yolk sac nearly disappeared, and the larvae (5.4 mm in total length) with perfect eye balls began to swim for themselves for the first time. Also, the specialization between the gill arches and the ailmentary canal, the development of each fins except dorsal fin as well as the blood circulation obviously distinguished in this stage. The larvae whose total length was 5.68 mm was very brisk: also, the development of the dorsal fin rudiment, nearly perfect formation of each organs and the function of the upper and lower jaws were noticeably observed 5 days after hatching.

• Journal of Food Hygiene and Safety
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• v.23 no.2
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• pp.169-176
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• 2008

The subcronic toxicity of WK-38, a herbal preparation for the atherosclerosis, was examined in male and female Sprague-Dawley rats. WK-38 is composed of Rhei Rhizoma, Magonoliae Cortx, Moutan Cortex Radicis. Rats were treated with the test substance at a dose of 5 mg/kg, 50 mg/kg and 500 mg/kg intragastrically for 13 weeks. Control rats were treated with vehicle only. No death and abnormal clinical signs were observed throughout the administration period. Also there was no difference in net body weight gain, food and water consumption, organ weight, gross pathological findings, and urine analysis among the groups of rats treated with different doses of the WK-38. Hematological findings and biochemical examination revealed no evidence of specific toxicity related to WK-38. The results suggested that under the condition employed in this study no observation effect level (NOEL) of WK-38 would be 500 mg/kg/day.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.195-206
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• 1980

Fish were grown in a water recycling rearing system consisting of a filter system, of which the area is about $30\;m^2$ and the volume of filter gravels is about $15\;m^3$, 6 rearing and 2 supplementary tans about $7\;m^2$ of surface area each. The results for 180 days from April 18 to October 14,1980 are summarized as following: One rearing tank was used for main experiment stocked with an equal number, and weight of each Israeli strain and $F_1$, hybrid between this strain and Korean local strain of common carp. Gross total production was 461 kg with a net production of 395 kg, and the Israeli strain grew to about 8 times initial weight and the hybrid about 6 times. Based on an analysis of results of the above mentioned main experiment and the other miscellaneous fish grown in the remaining tanks, it was considered to be feasible to implement a commercial production in this system by improving parts of the system and adding a number of the units. A special problem seems to be an adoption of more effective aeration device when fish loading increases. A solid waste removal system was deviced by use of by-pass flow ana this system worked very efficiently in view of supply water economy. A serious problem encountered in this experiment was heavy outbreaks of the gill-fluke, Dactylogyrus sp. which was relatively easily eradicated with Dipterex or DDVP treatment in the first trials, but later on strains which were resistant to any of these chemicals appeared.

• Journal of Aquaculture
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• v.10 no.3
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• pp.289-300
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• 1997

Energy budget of mysid shrimp, Neomysis intermedia in Lake Kyongpo was determined at constant temperature (2$0^{\circ}C$). Energy used by reared mysids were calculated from data on feeding, growth, molting, reproduction, and metabolism. The Energy used by growth of juvenile and adult were 6.87 cal in females of 8.55mm in length, and 5.67 cal in males of 7.53mm in length, respectively. Molting losses were estimated to be 0.46 cal in females and 0.38 cal in males from juvenile to adult. Energy used in respiration were estimated to be 48.48 cal in females and 36.45 cal in males from juvenile to adult. The energy intakes from feeding were 84.15 cal in females and 67.09 cal in males from juvenile to adult. Energy losses by excretion were 10.36 cal in females and 6.46 cal in males. Thus, females assimilated 86.65% and males 81.99% of assimilated energy in somatic growth. The gross growth efficiencies (k1) showed 8.71% for females and 9.02% for males and the net growth efficiencies (k2) showed 10.05% for females and 12.36% for males. Maintenance costs were estimated at 66.48% of assimilated energy in females and 66.26% in males. Molting losses among the energy assimilated from juvenile to adult were estimated to be 0.63% in males and 0.69% in females.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.368-374
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• 1986

Liparis ingens (Gilbert et Burke) is a demersal fish belonging to Liparidae, widely distributed in the coastal waters of the east coast of Korea. On January 16, 1986, mature adults of Liparis ingens were captured by a demersal gill net near Chongdongchin-ri, Kangwon-do, Korea. The authors stripped eggs and milt, and fertilized on the ship. The eggs were incubated and the larvae were reared in laboratory. The eggs of this species are demersal and adhesive, and are pale yellow, containing many oil globules. Egg diameters were varied from 1.55 to 1.65 mm. The hatching took place in ca. 747 hours after fertilization at the water temperature of $7.09{\sim}10.99^{\circ}C$ and salinity $30.62{\sim}33.98\%0$. The newly hatched larvae were elongate in shape and $4.40{\sim}4.85mm$ in total length with $12{\sim}13$ (abdominal)+40(caudal)=$52{\sim}53$ myomeres. Many melanophores were distributed on the lower jaw, pectoral fins, yolk sac, and ventral line of the tail part. Three days after hatching, the larvae reached 5.15 to 5.25 mm in total length, and the yolk sac was almost absorbed. Some melanophores appeared on the back of auditory vesicles. Seven days after hatching, the larvae attained $5.75{\sim}5.85mm$ in total length.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.3
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• pp.209-219
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• 2016

The survey was conducted to investigate biomass and distribution of fisheries resources using a quantitative echo sounder and a fixed gillnet around Marado coast of Jeju to obtain the scientific basic data for dispute resolution with a large purse seine fishery and coastal fishing and policy establishment of reasonable fisheries resources. Hydroacoustic surveys were conducted six times (November 28~29, 2015 (night), February 23~24, 2016 (night) and March 3~4, 2016 (night/day), March 30~31, 2016 (night/day)) using a quantitative echo sounder. The pelagic fish densities were relatively higher around Marado in November 2015, February 2016 and March 3~4, 2016. However, demersal fish densities were relatively higher in Jeju coastal waters on March 30~31, 2016. Catch data using fixed gill net were used to calculate biomass. Based on the hydroacoustic data, fish length-weight function and target strength information of dominant fish, the biomass of fishes were estimated as follow: 5.64 ton CV = 70.2% at night on November 28-29 2015, 7.14 ton CV = 35.8% of pelagic fish and 530.77 ton CV = 34.6% of demersal fishes at night on February 23-24 2016, 2.34 ton CV = 56.7% of pelagic fish and 571.93 ton CV = 40.3% of demersal fish at daytime, 1.39 ton CV = 48.4% of pelagic fish and 194.59 ton CV = 54.3% of demersal fish at night on March 3~4 2016, 0.37 ton CV = 72.9% of pelagic fish and 338.79 ton CV = 99.7% of demersal fish at daytime, 0.24 ton CV = 21.3% of pelagic fish and 68.61 ton CV = 53.8% of demersal fish at night on March 30~31 2016.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.315-326
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• 1991

This study was tried for a mathematical approaches related to daily fluctuations in the stomach fullness of Agrammus agrammus. The specimen was collected by angling and gill net from September 1984 to August 1985 off Shinsudo, Samchonpo. Fullness of the stomachs was increased in the early morning and the late afternoon, decreased in the late morning, at noon, and during the night. That is, feeding activity of the fish was more intense at sunrise and sunset. Daily feeding activity of the fish in a day was divided into the time period of gastric evacuation and both feeding and gastric evacuation. Stomach fullness with the lapse of time in the time period of gastric evacuation was geometrically decreased. Stomach fullness in the time period of both feeding and gastric evacuation was affected by gastric evacuation rates, feeding rates, and maximum fullness of the stomach. These parameters were able to estimate from the method estimating the regression coefficient in the relationship between the time(t) and the stomach fullness$(F_t)$, or between stomach fullness at the time t and $t+\Deltat$. The rates of feeding and gastric evacuation were the highest in spring and the lowest in winter. The relationships between time(t) and stomach fullness$(F_t)$ in the time period of gastric evacuation and both feeding and gastric evacuation induced from hypotheses were respectively as follows. $$F_t=F_{to}e^{-r(t-to)}$$, $$F_t=F\infty-(F\infty-F_{to})e^{-(p+r)(t-{to})}$$

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.432-441
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• 1997

Stomach contents of fat greenling, Hexagrammos otakii were analyzed to understand feeding ecology of the fish in the coastal waters, Shinsudo, Sarhon. Specimens were collected by angling and by gill net from February 1984 to September 1985. The fish consisted of 4 age groups from 0 to 3. The food items of the fish changed slightly by seasons and with growth of the fish. Main preys were copepods, gammarids and caprellids for the fish of age group 0, gammarids and caprellids for age group 1, and brachyurans and carideans for age group 2 and 3. The prey composition of the fish were more varied by seasons than by ages. Food items was not different between male and female of the fish. The fish positively selected for gammarids, polychaetes and brachyurans, but negatively selected for gastropods. The degree of selectivities for the other preys were changed with growth. As the fish grows it consumed larger preys in case of small preys such as gammarids and caprellids, however, it did not consumed larger preys beyond an optimal size in case of large preys such as sphaeromids, brachyurans and polychaetes.

• Journal of Environmental Science International
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• v.21 no.10
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• pp.1275-1286
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• 2012

Coastal marine ecosystem plays important role of spawning and nursery grounds for fisheries resources. Yongil Bay is one of major coastal marine ecosystems, which is located in the southwestern East Sea of Korea. Species composition and abundance of marine organism in the Yongil Bay were investigated by season from March to November 2009. Gill net and pot fisheries were used for survey of pelagic and demersal species composition, and collected 106 species, 67 families, and 7 taxa of fisheries resources from the coastal ecosystem. Species were included 2 species in Ascidiacea, 2 species in Bivalvia, 6 in Cephalopoda, 22 in Crustacea, 5 in Echinodermata, 12 in Gastropoda, and 57 in Pisces. Diversity indices (Shannon index, H') showed seasonal variation with low value of 2.11 in winter, and high value of 2.63 in autumn. Main dominant species were Asterias amurensis, Pleuronectes yokohamae, Siphonalia spadicea fuscolineata, Trachurus japonicas, Sillago japonica, Conger myriaster, Volutharpa ampullaceal, Engraulis japonicus, Asterina pectinifera, and Portunus (Portunus) sanguinolentus that were occupied over 71.5% of total individuals, and 52.9% of wet weight. Seasonal variations of fisheries resources composition were discussed on correlationships with those of environmental factors in the coastal ecosystem of the Yongil Bay in Korea. Those results from this study will provide scientific data and information to develop the ecosystem-based coastal fisheries assessment and management system in Korea.