• Journal of Mushroom
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• v.11 no.4
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• pp.244-248
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• 2013

"Hwaseong 5ho" was developed by the method of Di-mon mating between monokaryotic strains derived from "Hwaseong 1ho" and dikaryotic strain "PSC109". The color of pileus was dark grayish brown, the shape of pileus was convex or infundibuliform. The length of stipe was longer and the thickness of stipe was some thinner than Suhan 1ho. Material properties of stipe of "Hwaseong 5ho" was higher in strength, hardness, chewingness and brittleness than Suhan 1ho, but similar in elasticity and cohesion. RAPD using URP-primer showed not the same between two strains. Days of primordia formation period were 22-27 days after spawning, that was a little later than Suhan 1ho. In the trial using culture box containing composted cotton waste, yield index of 'Hwaseong 5ho' was 16.6% higher than Suhan 1ho. The farm field trial were showed stable productivity in each different growing conditions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.6
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• pp.489-500
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• 1987

Annual reproductive cycle of Bluegill, Lepomis macrochirus (RAFINESQUE) were studied in the natural population. Based on these informations, reproductive mechanism of the fish including activation, degeneration and remature were examined under the controlled conditions of temperature and photoperioe. In the natural populations, gonads began to grow with the temperature increase in March ana matured in June, and spawning occurred in July. With the onset of the shorter day-length and the maximum temperature condition in August, the gonads began to degenerate. Resting stage was continued during winter season. In the laboratory-reared population, activation of the gonads was initiated by the complex environmental factors including higher temperature$(>15^{\circ}C)$ and longer photoperiod $(>14L)$. For the maturation, photoperiod of more than 14 hours was critical. Under this condition higher temperature was the only compensative factor. Regeneration of the gonads was induced by higher temperature$(>25^{\circ}C)$ and the shorter photoperiod accelerated the regenerative processes. Even from the resting stage the gonads can be induced to matured stage by the longer photoperiod $(>15L)$. Based on these observations, the reproductive rhythm of this fish is supposed to be artificially controlled.

• Journal of Mushroom
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• v.3 no.4
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• pp.154-158
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• 2005

The results were as follows; 3 additives(rice bran, wheat bran and soybean bran) to the Quercus dentata sawdust were applied at 10, 20 and 30%. High yield was recorded at 20% of rice bran and wheat bran and 30% of soybean bran. Among various sawdust media, the cultivation with the Quercus dentata sawdust alone showed the most favored growth index, such as 22 days of full mycelial growth, 11 days of pinheading from spawning and 23.5g per $1,200m{\ell}$ bottle. In the size of bottles, the lowest infection ratio was 5 % at $1,200m{\ell}$ bottle. In the growth characteristics with the bottle size, Reishi at $1,600m{\ell}$ bottle showed best result when it is observed for 13~15 days in pinheading from spawing, 36~37 days in fruit bodies growing and 26.7~29.3g yield per bottle. The highest yield per area was 6.4kg at horizontal bed with 218 bottles per $3.3m^2$. The Reishi produced in $1,600m{\ell}$ bottle with horizontal cultivation had less number of fruit bodies and best yield, thus it is determined to be the most economic method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.659-663
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• 1999

Gametogenesis, reproductive cycle, condition factor, and meat weight rate of the surf clam, Tresus Keenae were studied by histological observations and morphometric data based on the samples which have been collected from the south coast of Korea, from January 1995 to February 1996. The annual ranges of the mean seawater temperature and specific gravity in habitat of the surf clam were $4.9\~24.9^{\circ}C$ and 1.0210$\~$1.0266, respectively. Monthly changes in the condition factor showed in a wide range from 0.2381 to 0.2827, began to increase in January and reached the first maximum (0.2827) in April. And then the value rapidly decreased in June, thereafter, reached the second peak (0.2812) in August. The condition factor of this species showed the two peaks, and gonadal development reached sexually mature and ripe conditions during the period of these two peaks. The meat weight rate ranged from $38.0\%$ to $46.4\%$, and its change showed a similar tendency with the condition factor. The reproductive cycle of this species can be divided into five successive stages: in both sex, multiplicative (December to January, July to August), growing (January to February, September to October), mature (February to April, September to November), spawning (April to June, September to November), and degenerative and resting stage (May to July, November to January).

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.50-56
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• 2023

This study is the first to report the biometric information between the length and weight relationships (LWR) and seasonal body condition factors (K) of Sebastes zonatus Chen & Barsukov, 1976 and Thamnaconus modestus (Günther, 1877) inhabiting the waters off Ulleung-do and Dokdo. The LWRs in spring and summer, and all seasons combined were highly correlated (r²>0.959), and the regression slopes of LWRs were significantly different between the spring and summer in both species. The body conditions of the two fish were significantly higher during the spring than during the summer, reflecting their fatness in relation to spawning. The results from this study contribute to the understanding of the biology of S. zonatus and T. modestus and provide useful data for the development of conservation and management plans for these species.

• Journal of Life Science
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• v.34 no.4
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• pp.264-270
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• 2024

This study is conducted to analyze environmental factors that affect the ecology of boreal digging frog and use them as basic data for selecting (or creating) suitability of alternative habitats for survival and monitoring method from 2020 to 2022 after boreal digging frog were relocated to the alternative habitats in 2019. Analyzing the environment of the alternative habitats showed that the criteria suited the followings: distance from wetlands, grasslands and rivers was within 5 m, the low-rise grassland was 6,000 m², soft soil was at a depth of ≥20 cm, and the area of permanent wetlands was 5,000 m² wide. As a result of the correlation analysis between meteorological factors and population (n) and breeding, there was a significant correlation between rainfalls and breeding (p<0.01). During the monitoring, it was confirmed that the SVL (Snout-Vent Length) and BM (Body Mass) of the translocated population were maintained (p>0.05), and it was found that the proximity of the habitat and spawning pond, securing food space (grasslands), soil quality, and wetlands could function as an alternative habitat if conditions were met. As a result of analyzing the meteorological factors affecting the population of boreal digging frog, the SVL had a statistical impact on the minimum temperature, maximum temperature, relative humidity, and the rainfall (p<0.05). In the case of breeding, rainfall was found to be affected (p<0.01), and the population was statistically affected by the average temperature, minimum temperature, and relative humidity (p<0.05).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.239-252
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• 1981

The East China Sea is an important region as nursery and spawning grounds for pelagic fishes such as jack mackerel, common mackerel etc. , and thus constitutes a major fishing area for purse-seine fishery. The environment surrounding in this region is under the influence of the Yellow Sea Cold Water, China Coastal Water and Kuroshio Current. The purpose of this study was to clarify the effects of oceanographic conditions and thermal fronts on the formation of the fishing grounds for the mackerels in the East China Sea. Through the analyses of fisheries statistics during 1968-1976 and temperature data, the following facts are found: 1) Approximately $70\%$ of the total mackerel(common) catches appeared to be come from the Tsushima Current region which includes Sakai coast of the Japan Sea, eastern Tsushima and Shirase Island, and Jeju Island of Korea. This area covers only about $8\%$ of the East China Sea. 2) Main fishing grounds for the jack mackerel are also centered around the area of southwestern Goto, Shirase and eastern Tsushima Island where the catches accounted for about $54\%$ of the total jack mackerel catches. 3) Fluctuations in annual catches are relatively small in the Tsushima Current region, compared to other regions such as Yellow Sea, southwestern coast of Kyushu and mid-western part of the East China Sea, where the fisheries yields varied considerably due to unstable fishing conditions. 4) It appears that the fishing grounds for the jack mackerel are mainly distributed along the warmer region ($15-20^{\circ}C$) of the thermal front, and those for the common mackerel are in somewhat colder region ($13-16^{\circ}C$) in the Tsushima Current.

• The Korean Journal of Malacology
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• v.18 no.2
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• pp.83-91
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• 2002

Reproductive cycle of natural population and artificial control experiments of gonadal development by the conditions of water temperatures-feeding and starvation of Ruditapes philippinarum were investigated by histological observations. The reproductive cycle of natural population in females and males can be categorized into five successive stages; early active (February to March), late active (April to May), ripe (April to August), partially spawned (May to October), and spent-inactive stage (August to March). In the artificial control experiments, gonadal development of this species was inhibited by the low water temperature (10$^{\circ}C$). In the experimental group which was exposed to artificial high water temperatures of 19$^{\circ}C$ and 22$^{\circ}C$, gonadal development was accelerated by the higher water temperatures and was faster (about one month) than that in natural populations. In the high water temperatures-feeding experimental group, the gonadal developmental phase was faster in the small-size group than that in the large-size group, and was faster in lower water temperature (10$^{\circ}C$)(p=0.01). The gonad developmental phases in the high water temperature (22-28$^{\circ}C$)-starvation experimental group showed faster (paired sample t-test, p=0.004) than those in the high water temperature-feeding group in females and males. In the high water temperature-feeding experimental group of female and male gonadal developments of small sized group were more sensitive than those in large sized group after 42 days cultivation, However, the gonadal development of male was more sensitive to the lower water temperature than female. On the whole, sexual maturation in the high water temperature experimental group was faster than those in the low water temperature group, and showed a significant difference (paired sample t-test, p=0.001) between female and male. In the starvation experimental group after 42 days, gonadal developments in the high water temperature-large male group showed faster than those in the high water temperature-large female group. However, in small size, gonad developmental phases showed the same pattern between feeding and starvation experimental groups. During the main spawning season, in the high water temperature-starvation experimental groups in females and males, their gonadal development showed faster than that in higher water temperature-feeding experimental group regardless of their sexes and individual sizes and showed a significant difference (paired sample t-test, p=0.004).

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.130-142
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• 2007

This study was to examine impacts of turbid water on fish community in the downstream of Yongdam Dam during the period from June to October 2006. For the research, we selected six sampling sites in the field: two sites were controls with no influences of turbid water from the dam and other remaining four sites were the stations for an assessment of potential turbid effects. We evaluated integrative health conditions throughout applications of various models such as necropsy-based fish health assessment model (FHA), Index of Biological Integrity (IBI) using fish assemblages, and Qualitative Habitat Evaluation Index (QHEI). Laboratory tests on fish exposure under 400 NTU were performed to find out impact of turbid water using scanning electron microscope (SEM). Results showed that fine solid particles were clogging in the gill in the treatments, while particles were not found in the control. This results indicate that when inorganic turbidity increases abruptedly, fish may have a mechanical abrasion or respiratory blocking. The stream health condition, based on the IBI values, ranged between 38 and 48 (average: 42), indicating a "excellent" or "good" condition after the criteria of US EPA (1993). In the mean time, physical habitat condition, based on the QHEI, ranged 97 to 187 (average 154), indicating a "suboptimal condition". These biological outcomes were compared with chemical dataset: IBI values were more correlated (r=0.526, p<0.05, n=18) with QHEI rather than chemical water quality, based on turbidity (r=0.260, p>0.05, n=18). Analysis of the FHA showed that the individual health indicated "excellent condition", while QHEI showed no habitat disturbances (especially bottom substrate and embeddeness), food-web, and spawning place. Consequently, we concluded that the ecological health in downstream of Yongdam Dam was not impacted by the turbid water.