• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.49-54
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• 2017

We collected and reared Theragra chalcogramma walleye pollock brood-stock for use in natural spawning tests and undertook to obtain domestic pollock via fertilized egg capture, development of fertilized eggs, and absorption of yolk sac after hatching. Whole pollock were caught with trammel and set nets and immediately placed in a deep-sea water tank. Adults were the most common pollock age group (43.0%; n = 86) among the 254 pollock captured in March 2014 with 57.9% (n = 147) being captured off Southern Gosung, Korea. The main spawning period of pollock is February (spawning phase of 91% of pollock). From the deep-sea tank, we collected 1640 mL of naturally fertilized eggs (~820,000 eggs) from 12 spawning events occurring between February 4 and 22 2015. The floating/ live eggs were maintained in deep-sea water tanks at $5.5{\pm}0.2^{\circ}C$. Egg size was $1.5{\pm}0.03mm$. Six hours after fertilization the eggs were at the 2 cell stage, and the eggs hatched approximately 340 hours after collection. At hatching, larval length and yolk sac area were $5.2{\pm}0.25mm$ and $9.5{\pm}1.00mm^2$ (100%), respectively. Four days after hatching, the yolk sac area was $2.2{\pm}0.53mm^2$ ($23.1{\pm}5.55%$). This is the first report of collection of naturally fertilized eggs from pollock and their subsequent hatching while held in an indoor deep-sea water tank. The results suggest that such collection could assist in the recovery of pollock resources and the possibility of domestic rearing of cultivated larvae.

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.177-183
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• 1999

This study was conducted to observe the spawning behavior and early life history of chinese minnow, Rhynchocypris oxycephalus reared in the laboratory. The spawning period of Rhynchocypris oxycephalus is from May to June in nature. The eggs of Rhynchocypris oxycephalus were spawned on the sand and surface of the gravel. The fertilization eggs were demersal in shape and adhesive, released as a clump forming a thin layer and their diameter were 1.70~1.90mm (mean 1.80 mm, n=20). Hatching of eggs was started in 88 hour 45 minute after fertilization at water temperature $19{\pm}0.5^{\circ}C$ and finished in 90 hour. Newly-hatched larvae were measured 4.87~5.02 mm in total length (TL, mean 4.94 mm), mouth and anus were not opened. 6 days old larvae were 6.32~6.56 mm in TL (mean 6.44 mm). Yolk sac was almost absorbed, mouth and anus was began to open. 13 days old larvae were 6.74~6.91 mm in TL (mean 6.82 mm). Part of Dorsal fin was began to rising and myomere number was 15+23=38. 25 days after hatching, total length of larvae was 8.45~8.60 mm (mean 8.52 mm). Dorsal and anal fin rays became differentiated, and also caudal part of the notocord flexion was achieved at $45^{\circ}C$. In the time, growth rate was higher than the other stage. Aggregate numbers of all fin rays were completed at 16.39~16.57 mm in TL (60 days after hatching), at which time the larvae reached the juvenile stage, but fin-fold on ventral was remained yet. External features of adult specimens were almost completed at 80 day old juveniles (18.69~18.87 mm in TL).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.6
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• pp.586-593
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• 1985

The rose bitterling, Rhodeus ocellatus (KNER) is commonly distributed in the fresh waters of Korea and Japan. On January 15, February 15, and March 18 in 1984, mature adults of rose bitterling were caught in the watercourse of Maeri, Kimhae, South Korea. The authors fertilized the eggs employing dry method in the laboratory on May 7, 16 and 25 in 1984. Hatched larvae were reared in small aquariums at $17{\sim}25.5^{\circ}C$ (average around $21.2^{\circ}C$). Mollusks, Anodonta woodiana in the gill chamber of which, rose bitterling lay eggs were caught in order to study natural spawning of the rose bitterling in the same watercourse. The eggs of this species are not adhesive and demersal. The size of the eggs varies from 2.54 to 2.75mm in long diameter and 1.45 to 1.65mm in short diameter. The eggs are cylindrical in form when they are extruded from ovipositor, immediately after entering water, but they acquire their distinctive form of a greatly elongated pear. Hatching took place in ca. 39 hours after fertilization. The newly hatched larvae were $2.65{\sim}2.70mm$ in total length possessing yolk sac and 13-14 myotomes. Thirteen days after hatching, the prelarvae attained 6.5 mm in total length, and the first melanophores appeared on the head, and the anterior part and sides of the yolk sac. One month after hatching, the postlarvae attained 8.5mm. in total length and emerged from the gills of the mollusks. Then the yolk sac was completely resorbed. Two months after hatching, the rose bitterling attained 14.4mm in total length, and entered the fingerling period of life. All the rays already present were the D. III, 11-12, A. III, 11-12, P. 10, V. 7. and a distinguishing, feature is the presence of a black pigment spot in the lobe of the dorsal fin.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.309-318
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• 2004

Acute toxicity test and chronic toxicity test were conducted with killifish (Oryzias latipes, Medaka) to evaluate toxicity effect of pesticides. Acute toxicity test was investigated mortality in 48 hours and 96 hours after treatment, chronic toxicity test was examined with the early life stage of 30 days after hatching be started embryos of Medaka. The test substances were two pesticides, Carbosulfan and Phenthoate, applied to the paddy rice plant and well-known to the high fish toxicity. As the result of acute toxicity test, median concentration $(LC_{50})$ at 96 hours in Medata was Carbosulfan 0.102 mg/L and Phenthoate 0.167 mg/L, and Fish early life stage toxicity test was conducted on basis of the result of acute toxicity test and concluded from the investigation of hatching success, period of hatching, survival post hatching, length and weight of surviving fishes and abnormal fish. The results of early life stage toxicity test were represented by no observed effect concentration (NOEC), lowest observed effect concentration (LOEC) and maximum acceptable toxicant concentration (MATC). NOEC was Carbosulfan 0.0067ppm and Phenthoate 0.011ppm, LOEC of PCP-Na, Carbosulfan and Phenthoate were 0.017ppm and 0.029ppm, MATC of Carbosulfan and Phenthoate were 0.011ppm and 0.018ppm. These studies will be expected to supply more varied chronic toxicity effects at lower concentration than acute toxicity test. Therefore, evaluation data will be more realistic and the risk assessment of pesticide will be leveled up.

• Korean Journal of Ichthyology
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• v.12 no.2
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• pp.129-136
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• 2000

The aucha perch, Coreoperca kawamebari was collected in Tam-jin river from February to June 1998. It was reared in the laboratory and observed the spawning behavior and early life history. Spawning season was from mid of April to the end of May in the Tam-jin river. The fertilized eggs were demersal of adhesive, transparent and spherical in shape. Egg diameter was 2.21~2.65 mm with several oil globule of 0.058~0.343 mm. Hatching occurred about 194 hours 23 minutes after fertilization at water temperature of $18{\sim}22^{\circ}C$. Newly-hatched larvae were 5.09~5.68 mm in total length(TL, mean: 5.38mm) with 10~11+18=28~29 myotomes and opened mouth and anus. Melanophores were distributed on the eye lens, on the head, around the yolk, on the dorsal part and the abdominal region of the trunk. After hatching 5 days larvae attained 6.12~6.68 mm in TL (mean: 6.47 mm), and the yolk sac was completely absorbed and transformed to postlarva stage. The larvae reached to the juvenile stage with all the fins were formed with complete set of fin rays (D. XII-12~13; A. III-8~10; P. 11~13; V. I-4~5) at the 22 days after hatching and of the larvae was 11.54 mm in total length. In 32 days after hatching, the juvenile was 13.05 mm in TL. This period was similar to adult in body form and the spot.

• Korean journal of applied entomology
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• v.26 no.2 s.71
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• pp.71-81
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• 1987

This study was conducted to study the effects of temperature on the oviposition, feeding and emergence of the azuki bean weevil(ABW) (Callesobruchus chinensis L.) in the stored beans. And ovipositional preference, hatching and emergence on the preference and non-preference hosts were also investigated. ABW has four generations a year and overwinters as larva stage in the bean grains. Optimum oviposition temperature of the ABW ranges from $25^{\circ}C\;to\;30^{\circ}C$. Oviposition preference in different hosts was in the order of azuki bean, mung bean, soy bean, kidney bean, black-soybean, pea. At $25^{\circ}C$, optimum development temperature emergence of period the ABW averaged 29 days on azuki bean, 31 days on mung bean, 49 days on soy bean, 46 days on black-soybean, 34 days on Pea. Percent hatch in different hosts was in the order of azuki bean, mung bean, soy bean, pea, black-soybean, kidney bean. But percent emergence was in the order of azuki bean, mung bean, pea, black-soybean, kidney bean. Especially, in azuki bean and mung bean, percentage of hatching and emergence was very high. And in soy bean and black-soybean, percentage of hatching was high but emergence was low. The kidney bean was hatching but not emergence at all. The longevity at the different temperatures appeared to be $4{\sim}5$ days at $35^{\circ}C,\;5{\sim}7$ days at $25^{\circ}C{\sim}30^{\circ}C$, $10{\sim}15$ days at $20^{\circ}C\;and\;19{\sim}24$ days at $15^{\circ}C$. Kidney bean of feeding non-preference host oviposited at Seed coat and Endosperm, but no larva developed. And cotyledon and embryo parts were not oviposited at all. The percentage of germination of egg laid bean grain and damaged bean grains was low. Especially, the percentage of germination of damaged bean grains was 0% on azuki bean, 5% on black-soy bean, 7% on Pea.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.2
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• pp.305-312
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• 2020

Objective: The present trial was conducted to determine the influence of different dietary fatty acid (omega-3 and omega-6) sources on reproductive performance of female broiler breeders and growth performance and carcass traits of their progeny. Methods: Two hundred and twenty, 25 weeks old Ross-308 male (20) and female (200) broiler breeders were used in the experiment for the period of 6 weeks. All birds were randomly divided into four dietary treatments (containing 2% soybean oil, 2% sunflower oil, 2% flaxseed oil, and 2% fish oil) each with five replicates of one male and ten females. Throughout this experiment hatching performance of broiler breeders, progeny growth performance and carcass parameters were recorded. Results: The results showed that the inclusion of different fatty acid sources in female broiler breeders diet had no significant effects (p>0.05) on number of fertile eggs, post-hatch mortality, and fertility rate. The soybean oil supplemented group had significantly (p<0.05) higher late embryonic mortality compared to other three treatments. Conclusion: It was concluded that inclusion of 2% of different sources of omega-3 and omega-6 fatty acids (especially 2% flax seed oil) in broiler breeders' diet can reduce late embryonic mortality. The other reproductive characteristics of parents and growth and carcass characteristics of progeny remained unaltered by dietary sources of omega-3 and omega-6 fatty acids.

• Journal of Forest and Environmental Science
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• v.34 no.4
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• pp.275-283
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• 2018

This study created the running water (Bandibooliwon) and lentic water (Sooryunwon) artificial habitats of Luciola lateralis in Hwadamsup, Gwangju-si, Gyunggi-do from April 2014 to February 2016. Through various habitat types, metapopulation was formed, and more sound population was induced to be maintained via interactions between habitats. We investigated coenosite at the habitat creation-target site, and 20 species in the lentic water site and 38 species in running water site were found. After releasing L. lateralis, we checked the status of settlement of L. lateralis larvae through traps and macroscopy, controlled the flow velocity of the habitats in line with the life cycle of L. lateralis (hatching, larva period, landing, pupation, copulation, and oviposition), and shaped gentle slope at water side, and planted moss. We artificially supplied melanian snails (Semisulcospira sp.), the food source, in the running water site and induced stable feeding. Also, We created artificial insectary, bred larvae stably in winter, and secured firefly population for a festival. Through night time observation, the time most suitable for a festival was confirmed to be from 20:30 to 22:00.

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.175-178
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• 2011

Yeonnokjam is a newly bred high yield special silkworm strain for spring rearing, bred from Japanese originated green cocoon spinning strain Jam 315 and Chinese originated white cocoon spinning strain Jam 316. This strain showed high hatching ratio of 96% and high healthiness of 96.7% of pupatin ratio. And its spins heavier cocoon with somewhat shorter fiber length but thicker fineness. The merits of these_strains are short larval period and labor saving, and its breeding goals are producing polish green silk and use for education.

• Korean journal of applied entomology
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• v.37 no.2
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• pp.159-162
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• 1998

Effect of temperature on oviposition and developmental period of Oulema oryzae K. on riceplant were investigated. With the given set of temperatures of 15, 20, 23, 25, and 28"C, developmentalperiod from egg to adult emergence was shorten as temperature increased. Average number of eggs perfemale 0. oryzae increased as temperature increased from 15$^{\circ}$C to 23"C, then decreased at 25$^{\circ}$C and 28"C. Based on this result, developmental threshold temperatures for egg was estimated to be 6.4"C. Totaleffective temperatures above the thresolds required for hatching were estimated to be 75.8 degree-daysfor egg. It seemed that the optimum temperature for oviposition of Oulema oryzae on rice plant was 23"C.a oryzae on rice plant was 23"C.quot;C.