• Korean Journal of Ichthyology
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• v.25 no.2
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• pp.82-89
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• 2013

The spawning behavior, development of eggs and larvae of the Five striped damselfish, Abudefduf vaigiensis were studied. The Five striped damselfish were caught at Dolsan Island, Yeosusi, Jeollanamdo from May in 2011. As a result of observation, male fish attracted female after cleaning the rock. Female left after spawning and male protected their eggs until they had hatched out. The fertilized eggs were elliptical in shape (mean long diameter: 1.06 mm; mean short diameter: 0.55 mm) and transparent. Larvae hatched at 53 hrs after fertilization in $24.5{\sim}26.5^{\circ}C$(mean $25.0^{\circ}C$). The newly hatched larvae were 2.55~2.86 mm (mean 2.71 mm, n=10) in total length and their mouth and anus were already opened. They began to eat rotifer and transformed to postlarva stage. 3 days after hatching postlarva was measured 2.74~2.97mm(mean 2.84 mm, n=10) in total length. 10 days after hatching postlarva was measured 3.85~4.20mm(mean 4.00 mm, n=10) in total length with dosal fin rays IV-5; ventral fin rays I-3; caudal fin rays 1~2.

• The Korean Journal of Ecology
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• v.26 no.1
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• pp.1-4
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• 2003

In diurnal activity of the black-crowned night herons on breeding season, activity budget was that male were standing(29.5%), preening(21.5%), comfort(10.9%), and female were resting(26.3%), repairing (18.4%), preening(15.3%) in sequence. Activity budget was high significant between male and female(p<0.01). In case of activity-time budget sequence, male was standing(38.7%), locomotion(33.8%), preening(11.5%), and female was resting(55.4%), standing(18.4%), preening(9.4%). Therefore, activity-time budget was significantly different in male and female(p<0.01).

• Korean Journal of Poultry Science
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• v.47 no.2
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• pp.83-93
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• 2020

The purpose of this study was to evaluate the effects of stocking density on feather condition, egg quality, blood parameters, and corticosterone levels of laying hens reared in conventional cages. A total of 500, 28 weeks-old Hy-Line Brown laying hens were evenly assigned to two stocking densities (750 and 500 ㎠/bird). There were 50 replicates of each treatment, each consisting of 750 ㎠/birds (n=6) or 500 ㎠/bird (n=4) birds in a cage, respectively. We observed an increase in the laying period of, the group that was assigned 500 ㎠/bird, however, this group experienced significant feather damage when compared with the group allotted 750 ㎠ bird. There was no effect of stocking densities on egg quality. These results suggest that the 500 ㎠/bird stocking density in the conventional cage can negatively affect feather condition and cause the birds to experience more stress than the group allotted 750 ㎠/bird.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.335-343
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• 2003

An experiment was conducted to investigate types of injury inflicted by the stone leek leafminer, Liriomyza chinensis Kato (Diptera: Agromyzidae) on welsh onion. A feeding scar made by an adult female was a hole round in shape, with diameter of 0.08 mm and 0.48 mm in lesion, resulting in a white spot, many of which often form vertical dotted lines on a leaf. Egg spots were oval with 0.1 ${\times}$0.14 mm in size, one or several of which often form a V-shape in group. Feeding by adults began immediately after emergence and was very active from 4th to 5th day. Oviposition was done from 2nd to 6th day after emergence. In both feeding and oviposition, they were more active in the day time. Larvae after emergence crawled up the leaf at first, and then moved up and down to feed on mesophyll. When in high density, they feed on leaf from leaf tip to bottom, and let the leaf die. Area of damage per one larva was calculated as 72.1 $\textrm{mm}^2$. The aged larvae escaped from the leaf in early morning, usually between 5 and 7 am. Most pupation sites were distributed near plants,5cm in soil depth and within 10 cm away from the plant. Pupae of L. chinensis overwintered 10cm below soil surface and emerged from early May to late June the next year Adults then moved to welsh onions near over wintering sites, nursery, transplanted, and levee.

• Journal of Animal Environmental Science
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• v.6 no.2
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• pp.91-96
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• 2000

This study was carried out to determine the effect of sound stimulation on growth performance, feeding behaviour and egg production of laying hens. A total of 180 laying hens(4 weeks old) were alloted to 18 cages with 10hens per cage and 6 cages per treatment. Laying hens were exposed to three sounds: control, Leq 50dB and Leq 75dB. The growth performance was measured fro m4 weeks to 17 weeks of age, feeding behaviour was observed at 5weeks, 7weeks, 10weeks and 50 weeks of age using data from real-time videotapes, while eg production was recorded from 20 weeks to 50 weeks of age. Growth performance was improved in the sound stimulated laying hens from 12 weeks to 17 weeks of age. In the 50dB simulated laying hens spent more longer time for feeding than others during the experimental period. Egg production of 50dB stimulated laying hens from 20 weeks to 50 weeks was higher than others, however 75dB stimulated laying hens were significantly lower than 50dB stimulated hens(P<0.05). The results indicated that the growth and egg production of egg type chicken can be influenced by sound stimulation through physiological rhythm.

• Journal of Animal Environmental Science
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• v.19 no.2
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• pp.133-140
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• 2013

The aim of this study was to investigate the behavioral changes of laying hens in an aviary system. In this study, 500 laying hens (Hyline brown) were held in an aviary system in a open-type poultry house. The behaviors of laying hens were recorded using CCD cameras and a digital video recorder. The data were scanned every 2 min to obtain an instantaneous behavioral sample. In the behaviors of laying hens, 'Feeding' and 'Drinking' increased from 3 d placing chick and stabilized after 5 d placing chick. 'Perching' increased from 19:00 to 05:00, while 'Nest visiting' increased from 06:00 to 18:00. 'Aggressive behavior' decreased gradually after 5 d placing chick. These results suggest that the behaviors of laying hens are changed rapidly for about 5 days after placing chick and the behaviors of the laying hens are almost stabilized at 5 d placing chick.

• Korean journal of applied entomology
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• v.55 no.3
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• pp.235-243
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• 2016

The winter cherry bug, Acanthocoris sordidus (Thunberg), is an insect pest hat damages plants from Solanaceae and Convolvulaceae. The developmental period from egg to adult averages 76 days at $25^{\circ}C$. Adult egg-laying occurred irregularly via spawning, averaging 195 (up to 468) eggs per individual on the abaxial leaf surface of the host plant. Results of linear regression indicated that the lower developmental threshold temperature was $13.9^{\circ}C$ and the effective accumulated temperature was 526.3 DD. Data from a pepper field in 2015 indicated that overwintering adults first appeared during late June (daily average temperature = $25.7^{\circ}C$), reaching maximum density by early September. A choice test examining colonization preferences using a net cage and a Y-tube olfactometer revealed that females gravitated toward conspecifics (other females, males, or both), whereas males moved toward empty areas. Finally, we found that communal breeding results in a longer developmental period and higher eclosion rates than solitary breeding. Developmental periods and eclosion rates were also for colonies in a large space than for those in a small space. This outcome suggests that colonization effects on insect development are stronger in a smaller area.

• Development and Reproduction
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• v.10 no.2
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• pp.135-140
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• 2006

The small octopus(Octopus minor), a species in the cephalopod class spawns the fewer eggs compared with its relatives such as Octopus vulgaris and Octopus ocellatus and exerts special efforts in nursing eggs hiding in the deep cave beneath the mud flat. Correspondingly, its embryogenic process had been hardly observed. In this study, we induced the small octopus to spawn its eggs in the artificial spawning tube and to nurse the developing embryos under the periodical observation. The early embryogenic change in the fertilized eggs was appearance of blastodisc on the animal pole at 4 days after spawning. A mass of rudiments of several organs developed in the middle of the yolk sac at 28-th day and it moved gradually toward the animal pole. At 38 days after spawning, two eyes appeared on the head and the trunk with heart developed on the apical part of the yolk sac. At 45-th day of embryonic development, the trunk and head occupied a half of the egg capsule and consequently the yolk sac was reduced to a half of its original size. Two eyes became prominent at the bottom of the trunk with several spots at day 60. Embryonic development was completed at about 80 days after spawning and the arms stuffed the lower half of egg capsule. The young fry squeezed out of the egg capsules with their long and slender arms first and mantles later. Soon after hatching, it swam actively and squirted ink.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.2
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• pp.85-94
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• 2001

The vertical distribution and activity patterns of fishes during the evening and morning transitions were investigated acoustically and by pelagic trawling on October 2-10, 1997 in the Korean Eastern Sea. The acoustic data were collected from four stations with a scientific echo sounder operating at a frequency of 38 kHz, and the echogram was used to analyze the diel vertical migration of fish. Biological sampling was accomplished by pelagic trawling to identify fish species recorded on the echograms, and the species and length compositions were investigated. Vertical profiles of water temperature, salinity at the trawl station were taken with a CTD system and were related to the diel movement and the depth distribution of fish. During the day, one group of fish mainly distributed above the depth layer of 50 m, the other group was at deeper water, approximately 250 m, but began to migrate toward the surface before sunset with a time difference. During the night, they were dispersed between the surface and the depth of 125 m. Just prior to sunrise, the scattering layer was divided with 2 groups and began to migrate downwards, respectively. Several trials of pelagic trawling for scattering layers suggest that the most dominant scatterer in the survey area of this study was Japanese flying squid, Todarodes pacificus..

• Korean Journal of Ichthyology
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• v.13 no.3
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• pp.181-189
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• 2001

Spawning behavior of the Takifugu pardarlis (Temminck et Schlegel) was observed on the Jook-do coast in Tongyong from March 1997 to June 1999. The spawning ground was locted in the intertidal zone between Tongyong and Koje-do. Its bottom was mainly gravels and stones, and its depth was 0.5~1.0 m. Spawning season was from the end of the March to the middle of May. During the spawning season, the mature fishes formed school a of 10~30 individuals, then moved to the spawning ground together. When a mature female spawned eggs, the attendant males fertilized them at the same time. The fertilized eggs obtained from the parent fishes caught at the spawning ground were adhesive, opaque and spherical, measuring 1.14~1.24 mm (mean 1.19 mm, n = 50) in diameter with numerous tiny oil globules. Hatching period was about 205 hours after fertilization at water temperature of $18.0{\pm}0.5^{\circ}C$. The newly hatched larvae were 2.92~3.10 mm (mean 3.01 mm, n = 20) in total length (TL), had a large yolk, and 11~13+14~15 = 25~28 myomeres. At 5 days, the larvae had attained 3.79~3.85 mm (mean 3.82 mm, n = 20) in TL and had transformed into the postlarval stage. At 15 days, the postlarvae had attained 7.78~7.90 mm (mean 7.84 mm, n = 20) in TL. At 21 days, had larvae attained 10.15~10.27 mm (mean 10.21 mm, n = 20) in TL and had reached the juvenile stage. All fins were formed with a complete set of fin rays having the following counts: dorsal fin rays 11~12; anal fin rays 9; pectoral fin rays 14~15; caudal fin rays 11~12.