• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.4
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• pp.97-110
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• 2020

This study conducted observations at 72 traffic lights and road signs in Sejong-si, Korea from March to June 2019 in order to analyze nest-site, nest-site characteristics and feeding behavior in Tree sparrow (Passeer montanus) in urban. Feeding behavior during breeding season in 2019 was investigated at 10 Town representing traffic facilities installed on the road located in the center of the city and 10 Riverside Geumgang river's riverside road. We fitted both general linear model and regression model to our field data and estimated the spatial variation of initial date of the first feeding (i.e., being date of breeding) and the total number of caterpillar fed by parents per hour. Our results showed that the frequency of nest building on artificial structures, such as traffic lights, was about 26% higher and about 8 days earlier in the riverside. In particular, the first feeding was significantly faster when the nearest distance between nest to green field as foraging site was shorter whereas there was no significant effect of the number of nest within 50 meters on the first feeding. Number of caterpillars fed by parents was higher in the Riverside than in the Urban, and especially the number in the second brood was sharply decreased in the Urban. As we estimated average amount of caterpillars per hour to 446 traffic safety facilities in Sejong-si, it was estimated that Tree sparrows fed 18,742.8 caterpillars per hour during the breeding season. In this study, we showed that characteristics of nests built in artificial structures and feeding behavior in order to analyze effects of environmental condition in urban on life-history traits during the breeding season. Finally, we discussed the conservation of birds in urban and pest control effects.

• Journal of Life Science
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• v.29 no.10
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• pp.1120-1125
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• 2019

The short-lived nematode Caenorhabditis elegans has been used as a model organism for many studies, including lifespan extension. To screen common seaweeds for natural anti-aging agents, the lifespan of C. elegans (N2 wild-type strain) was measured by its hatch rate, growth rate, survival rate, chemotaxis, brood size, and egg-laying time after exposure to nematode growth medium (NGM) containing seaweed extracts. Approximately 30 animals synchronized at the first larval stage were incubated until they reached their adult stages before laying their eggs and were transferred to fresh NGM every 3 days. We also identified the major active compound from the seaweed by gas chromatography-mass spectrometry and tested its optimal dose for longevity. Of 13 common seaweed species, an ethanol extract of the brown seaweed Hizikia fusiformis showed the greatest effect on hatching, growth, and survival rates. The lifespan of C. elegans was significantly expanded 1.54-fold and 1.23-fold in the presence of the ethanol extract (0.05 mg/ml) and the main active component, fucosterol (0.05 mg/ml), respectively. Exposure to the ethanol extract also increased chemotaxis 1.13-fold, decreased brood size 0.74-fold, and shortened egg-laying time 0.96-fold. These results suggest that the aquaculturable H. fusiformis may be a promising source of a diet supplement to support health care.

• Journal of Life Science
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• v.9 no.4
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• pp.395-407
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• 1999

The queens of Korean native bumblebee species, Bombus ignitus were collected from the field in the spring of 1997 and reared under the various temperatures as 15$^{\circ}C$$\pm$1$^{\circ}C$, 2$0^{\circ}C$$\pm$1$^{\circ}C$, $25^{\circ}C$ $\pm$1$^{\circ}C$, 3$0^{\circ}C$$\pm$1$^{\circ}C$, 60%$\pm$5% of relative humidity and 14L : 10D, to investigate their ecological characteristics, as comparing with control(29$^{\circ}C$$\pm$1$^{\circ}C$, 60%$\pm$5% of relative humidity and red light). As a result, eggs were laid by foundation queen at 15$^{\circ}C$, but they didn't hatched out while at 2$0^{\circ}C$ eggs were laid by them and they hatched out. When a foundation queen laid eggs at $25^{\circ}C$ and they all were hatched out and normally grown. Finally they were developed to the normal colony. B. ignitus worker survived for 77days at 2$0^{\circ}C$, about 69days at $25^{\circ}C$, about 68days at 3$0^{\circ}C$ and about 63days at 29$^{\circ}C$(control). The first brood workers emerged in 25-27days from the egg which a foundation queen laid. At the various temperatures, the captive queens stand to lay eggs in about 18days at 15$^{\circ}C$, 15days at 2$0^{\circ}C$, 11days at $25^{\circ}C$, 11days at 3$0^{\circ}C$ and 4days in control. The first worker and the first drone from the egg cell of the collected queens appeared in about 27days and 72days at 2$0^{\circ}C$, 26days and 88days in $25^{\circ}C$, 24days and 65days at 3$0^{\circ}C$, 25days and 71days in control, respectively. In colony foundation, 33% of the collected queen at 2$0^{\circ}C$ and $25^{\circ}C$, 100% of the disposed queen at 3$0^{\circ}C$ and in control, and 67% of them at 3$0^{\circ}C$ and in control both produced new queens in 66days and 88days, respectively. The life span of the colony founded covered fro about 3 months at $25^{\circ}C$, 3$0^{\circ}C$ and in control. At lower temperatures, the life span of queen is shorter; 2 months at 15$^{\circ}C$ and 3 months at 2$0^{\circ}C$, respectively. A colony which normally developed, varied in size with rearing temperatures; about 20heads at 2$0^{\circ}C$, 482heads at $25^{\circ}C$, 330heads at 3$0^{\circ}C$ and 452heads in control. A foundation queen monthly oviposited 1.5egg cells at 15$^{\circ}C$, 3.0egg cells at 2 $0^{\circ}C$, 21.7egg cells at $25^{\circ}C$, 42.3egg cells at 3$0^{\circ}C$ and 47.0egg cells in control. As a colony developed in June and July, egg cells as well as daily average cells increased in number, as compared to those in May and August. Also, in June and July, interval(days) of egg laying is shorter than in May and August. Number of nectar pots during the colony development varied with rearing temperatures; 31pots at $25^{\circ}C$, 39pots at 3$0^{\circ}C$, 23pots in control. The emergence of new queen showed a distinctively different two patterns; early emerging type and late emerging type. Workers are rapidly increased from early in July to early in August at $25^{\circ}C$, but at 3$0^{\circ}C$ and in control, emergence of workers are remarkably increased from the middle of June and last until July. No new queen emerged at 15$^{\circ}C$, 2$0^{\circ}C$ and $25^{\circ}C$. New queens at 3$0^{\circ}C$ and in control emerged between late in June and early in July. Thus emergence of new queen was temperature dependent.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.397-401
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• 2011

This study was conducted to clarify the breeding ecology of tits Parus spp. used artificial nest boxes in a deciduous forest at the Ansung Campus, Chung-Ang University from March through July, 2006 to 2010. Varied tit Parus varius, marsh tit P. palustris and great tit P. major bred in artificial nest boxes during our study period. There were no differences in number of breeding bird pairs among different entrance diameters of artificial nest boxes. The number of breeding pairs of great tits was the most highest among tits and that of varied tits was the least. Great tits mainly used 40 mm and 35 mm artificial nest box entrance diameter and marsh tits preferred 30 mm entrance diameter. In three tits species, there were differences in first egg date, clutch size, brood size, egg incubation period, nestling care period and breeding success among study years. It is needed the study on long-term ecological research about breeding ecology of tits related with habitat conditions.

• Korean Journal of Ichthyology
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• v.29 no.3
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• pp.157-164
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• 2017

In 2015, a nervous necrosis virus (NNV) was isolated from sevenband grouper, Epinephelus septemfasciatus, maintained in land-based aquaculture system at below $12^{\circ}C$ in winter. Mortality was up to 30% in brood fish, over 4 kg of body weight. Moribund fish showed clinical sings typical of viral encephalopathy and retinopathy (VER), also called viral nervous necrosis (VNN), such as uncoordinated, corkscrew-like swimming behavior, belly-up at rest, darkening of body, cloudy eyeball and hyperinflation of the swim bladder. Aetiology of the disease was confirmed by gross observation of clinical signs, histopathology and molecular diagnosis. Histological studies revealed severe vacuolation and necrosis in the brain. Molecular diagnosis by revere transcription-polymerase chain reaction (RT-PCR) specific to batanodavirus yielded a positive result. The nucleotide sequences of the PCR-amplified fragment were 99.48~100% similar to barfin flounder nervous necrosis virus (BFNNV) genotype and most closely aligned with Pacific cod betanodavirus (PCNNV). This is the first report of natural batanodavirus, NNV infection in sevenband grouper reared in low water temperature during winter (below $12^{\circ}C$) in Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.261-263
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• 1976

In 1975, a trial for channel catfish spawning was made for the first time in Korea, by stocking 11 pairs of brood fish in a $470m^2$ earthen pond provided with 5 cans of 35 cm in diameter with depths of about 60 cm as spawning nests. The same trial and another pen cage method combined with pituitary injection were practiced in 1976. All these trials failed without any spawning. On the other hand 4 females and 1 male were put in a recycling water system indoor aquarium for exhibition purpose it late spring of 1976. After removing 3 females which were injured from being bitten by the male, remaining one pair of the catfish spawned successfully in July and the most eggs developed normally. The water in the recycling system showed the pH range of 7.2 to 7.4,and mean water temperature of every 10 day period of a month gradually increased from 19.3 to 23.6C until spawning. The outdoor .ponds where the spawning was failed received water from the same origin as the indoor recycling system, and the mean temperature of every ten day period ranged Iron 17.2 to $29.8^{\circ}C$ in 1975 and 19.7 to $28.4^{\circ}C$ in 1976 these being considered well falling in the optimum range for catfish spawning, but pH ranged from 7.3 to 9.5 under the influence of photosynthesis of algae and weeds in the ponds. The high pH value may suppress the spawning of catfish as pointed out by Nelson in 1957.

• The Korean Journal of Pesticide Science
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• v.10 no.3
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• pp.196-200
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• 2006

In this study we investigated fecundity and survivorship of four staple Korean freshwater cladocerans for their whole life to develop a new standard method used for ecological risk assessment of pesticide. The tested Korean freshwater cladocerans were Daphnia obtusa, Daphnia sp., Moina macrocopa and Simocephalus vetulus. In addition, standard test species, Daphnia magna endorsed formally by the major international organizations was tested together in order to compare with the reproductive characteristics of Korean cladocerans. A total of 358 young was produced by D. magna, whereas, 297 young was reduced by Daphnia sp. throughout the entire life. The average life span of Daphnia magna was 50 days much longer than any other Korean species. Nevertheless all of the Korean water flea tested showed good fecundity, produced over 60 young for 21 days as the validation criterion for reproduction toxicity test in Ecological Effects Test Guidelines published by USEPA. Especially Moina macrocopa produced their first brood in 4 days. Therefore 10 day reproduction test with Moina macrocopa may be an alternative good method to save cost and time to elucidating the effects of hazardous substances on the reproduction of aquatic invertebrates.

• 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.