• Korean Journal of Ecology and Environment
• /
• v.47 no.2
• /
• pp.82-90
• /
• 2014

To assess the adverse effects of suspended solids on fishes, the hatching rate of embryo, and survival and growth of larvae were measured with common fish species of river such as crusian carp (Carassius auratus), common carp (Cyprinus carpio) and medaka (Oryzias latipes). Bioassay on hatching rate of embryo was conducted with a range of turbidity as 10 levels from 0.2 to 8,080 NTU. Another bioassay on 4-day larval survival and 21-day larval growth were also conducted with a range of turbidity as 8 levels from 0.1 to 8,260 NTU, and 6 levels from 0.7 to 2,030 NTU, respectively. The hatching rate of C. auratus was not significantly different from that of control at turbidity below 4,040 NTU, whereas it decreased when turbidity was 8,080 NTU (p<0.05). The hatching rate of C. carpio was not affected by concentration of suspended solids. For O. latipes, the hatching rate significantly decreased from 254 NTU (p<0.001) and it was zero when turbidity was 8,080 NTU. The 4-day survival of larvae of all 3 species was not affected by turbidity, while the larval growth of all 3 species was significantly affected. The turbidity effect on the growth of C. auratus and C. carpio was observed from 7 days after the exposure at turbidity level of 145, 143 NTU, respectively. The turbidity effect on the growth of O. latipes was observed from 14 days after the exposure at turbidity level of 254 NTU. The results of this study will provide the basic information for the derivation of water quality criteria on suspended solids for the protection of aquatic ecosystem and the quantitative ecological risk assessment of freshwater environment.

• Korean Journal of Ichthyology
• /
• v.2 no.2
• /
• pp.159-168
• /
• 1990

Parental fish of R. uyekii(Mori) were colleted from the Nakdong River, Korea. Artificial insemination was carried out 4 times during June using the same pair (a female 52.70 mm TL and a male 56.80 mm TL). Unfertilized eggs are nearly spindly, opaque yellow in colour, measuring about 3.20-3.50 mm in length, about 1.50-1.80 mm in breadth. Hatching began about 50 hours after insemination at water temperature of $16.5{\sim}18.5^{\circ}C$. The newly hatched larvae are 4.10-4.50 mm in total length(TL), with 29-30 myomeres. Nine days after hatching, the larvae averaged 8.40 mm in total length and caudal notochord flexed at $45^{\circ}$. Eighteen days after hatching, total length reached 8.90 mm. The part of the fin-fold of the future dorsal and anal fins became high. Twenty-eight days after hatching, total length was 9.35 mm. The caudal fin-rays began to fork into two branches. The increased number of melanophores appeared newly on the head dorsal and anal fin-rays. The larvae reached the juvenile stage at 50-60 days after hatching and attained 14.50-16.20 mm in total length, and all fin-rays was formed.

• Korean Journal of Ichthyology
• /
• v.29 no.4
• /
• pp.261-266
• /
• 2017

Microphysogobio koreensis is an endemic Korean freshwater fish that is protected as an endangered fish by the Ministry of Environment in Korea. In this study, we attempted to investigate the spawning period and spawning characteristics of M. koreensis to obtain basic information for its conservation. Though natural and histological observation, the spawning season occurred between April and May, with peak spawning occurred in early May when the water temperature was $20{\sim}23^{\circ}C$. During the spawning season, males had a bright-orange body and a thick red horizontal line from the rear of the operculum to the caudal peduncle, along with a lateral line, while females had a dark brown body. Nuptial organ had not appeared. The number of eggs in the ovaries was 10,705~22,165 ($15,573{\pm}4,274$). The number and appearance ratio of mature eggs were 1,100~5,920 ($3,383{\pm}2,126$) and 10.3~44.8% ($22.4{\pm}15.6$), respectively. And the size of mature eggs was 0.60~1.00 mm ($0.74{\pm}0.06$).

• Korean Journal of Environment and Ecology
• /
• v.29 no.5
• /
• pp.718-728
• /
• 2015

The fish community and inhabiting status of introduced fish were surveyed at nine stations of Gangeungnamdae stream from September 2013 to May 2014. A total of 36 species of fourteen families were collected from the survey stations and among them, Pungitius sinensis was identified as endangered species. There were nine Korean endemic species (25%) including Coreoleuciscus splendidus. Dominant species were Rhynchocypris steindachneri (St. 1), Zacco koreanus (St. 2, 4, 5, 6), Ladislabia taczanowskii (St. 3)), Zacco platypus (St. 7, 8) and Tribolodon hakonensis (St. 9). Of the 11 introduced species fishes in Gangeungnamdae stream, L. taczanowskii, Pungtungia herzi, Coreoleuciscus splendidus, Squalidus gracilis majimae, Pseudogobio esocinus, Rhynchocypris kumgangensis, Z. platypus, Z. koreanus, Koreocobitis rotundicaudata, Liobagrus andersoni and Coreoperca herzi were released from Han river water zone in Korean. Rapidly expanded population and distribution of introduces fishes were Z. platypus, Z. koreanus, P. herzi and S. gracilis majimae, but L. taczanowskii, C. splendidus, R. kumgangensis were not rapidly expanded population. Settlement but very small population fishes were C. herzi and L. andersoni. When reduced 3% fishes of relative abundance with previous data (1973), R. steindachneri, Orthrias toni, Iksookimia pacifica, Plecoglossus altivelis, P. sinensis and Gymnogobius urotaenia, and R. steindachneri was most reduced from 56.1% to 12.9%.

• Korean Journal of Ecology and Environment
• /
• v.38 no.4 s.114
• /
• pp.445-453
• /
• 2005

Relative importance between bottom-up and top-down controls on phytoplankton dynamics was investigated in the Juam Reservoir, Chonnam based on the results from statistical analyses including regression and artificial neural network (ANN) modeling. Effects of nutrients on size-structured phytoplankton dynamics were explored by simple linear regression analysis and relative importance between bottom-up and top-down controls was estimated based on results from the artificial neural network analyses. Although there is a limitation in determining direct grazing effects since chlorophyll a : pheopigments ratios, indirect index for grazing activity rather than grazing rates or herbivores biomass were used, the results from regression analysis showed that nutrients especially orthophosphates were positively correlated with the phytoplankton biomass and chlorophyll a : pheopigments ratios were also positively correlated with the phytoplankton biomass at lower coefficient of determination ($r^2$) compared to orthophosphates. The simulation results from ANN suggested that the bottom-up mechanisms including water temperature and availability of nutrients, especially orthophosphates were more important than top-down mechanisms such as grazing in the phytoplankton dynamics.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.5
• /
• pp.671-676
• /
• 2005

A total of 50 individual catfish, the Tra (Pangasius hypophthalmus) cultivated in either floating cages (Tra-c) or in ponds (Tra-p) and the Basa (Pangasius bocourti) raised in three floating cages, were collected in two of the Mekong Delta provinces. The caudal fin of each individual fish was used for protein electrophoresis employing the SDS-PAGE method. The one fillet sides were used as a representative sample to determine the dry matter (DM), crude protein (CP), ether extract (EE) and amino acids (AAs). The catfish oil was extracted from the belly fats, and the fatty acid (FA) composition was analyzed. There were 21 bands of the Tra and the Basa. Protein bands of the two varieties were 28.6-33.3% polymorphic, while polymorphic individuals of the Tra ranged from 80.0 to 100.0%, and the Basa was 90.0% polymorphic. The phenotypic diversity (Ho) of the Tra ranged from 1.71 to 1.80, while the Basa ranged as high as 2.14%. Diversity values (H$_{EP}$) for genetic diversity markers were equal in the Tra and the Basa. The sum of the effective number of alleles (SENA) of both varieties ranged from 3.40 to 3.83 for the Basa and the Tra, respectively. The lower values of Ho and SENA, as compared with those of the fresh water prawn (Macrobrachium equidens) in the area, would suggest that the species with the low values will become extinct due to inbreeding; the gene pools of each observed population were below a suitable threshold. Many of the differences in the nutritional values of the Tra-c, the Tra-p and the Basa were measured; their nutrient values were comparable to fishmeal or fish oil. Most of the DM, CP, and EE were higher in the Tra, especially in the Tra-c. The essential AA content, especially that of lysine, was highest in the Tra-c, next highest in the Tra-p, and lowest in the Basa. Therefore, the amino acid patterns were closer to the ideal patterns in the same sequences. In contrast, the essential FAs were concentrated in the Basa fish oil. It was found that suitable selection of parents for seed production is required to avoid inbreeding. Catfish may be valuable sources of nutrition for both humans and animals, and the differences in their nutritional values by variety and/or management must be taken into account.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.7 no.4
• /
• pp.195-203
• /
• 1974

The individual production rate of Plecoglossus altivelis was studied from the 18th of June to the 25th of September (99 days) 1973, when the fish grow best at Gangjeong Stream, Jeju Do, as one of the ways to find out the reasons why the size of P. altivelis of Jeju Island is smaller than that of other places. The results obtained are as follows : 1) The indivudual production rate of the fish in the Gangjeong Stream during the summer 1973, was estimated as shown in Table 6. 2) The individual production rate of the fish and standing crop of algae on stones in the Gang-jeon Stream were no more than $7.2\%$ and $6.2\%$ respectively, when compared with those of the Ukawa River (which is located in Japan), thus the individual production rate of the fish at Gang-jeong Stream being very poor. 3) Population density was 5.2 individuals average per square meter during the research period. This is beyond the estimated density limit, i. e., 4.8 individuals per square meter, for the standing crop of algae on stones. 4) The period that the individual production rate of the fish was the most brisk during the summer in this stream was from August to September in 1973. 5) The poor individual production rate is primarily regarded due to insufficient gross ingestion. The reasons seemed to be insufficeient productivity of algae on the bottom stones, over-population density of the fish, and the lowered activity of ingestion due to low water temperature in daytime as compared with other places. Thus, the production rate of Plecoglossus altivelis in the Gangjeong Stream during the summer was greatly influenced by these factors.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.7 no.3
• /
• pp.126-144
• /
• 1974

Adult female prawn, Macrobrachium japonicum, which used for this work were collected at the river Simanto, Shikoku in Japan, and removed in the laboratory. Newly hatched larvae from an adult reared in circulation-filtered aquaria, which is controlled under the conditions of water temperature $26\pm0.3^{\circ}C$, chlorinity $6.21-6.45\%$ Cl, pH 8.0-8.1, illumination 3000 lux, and fed on Artemia salina nauplius sufficielltly For a period of rearing of zoea larvae, big individuals-individual varying bodies, comparing with standard bodies in the same aged individual group, are occasionally appeared from fifth zoea larva stage, and occurence of it be tempted to relate with the factor of trophic condition. This paper was dealt with a comparative morphological view on big individuals, comparing with standard type in the same aged group, to solve the problem on (1). the existence or nonexistence of stages which it is easier to occurence of big individuals, (2). the rate of development in several appendages of an individual, and (3). a happening of skipping whether it certainly occur or not, during newly hatched zoea larvae develop to post larva stage. The results of the above are as follow: (1). the stages which is easier to occur of big individuals are fifth and seventh stage in this species, (2). even same individual, development of several appendages differs more or less on the rate of growth in accordance with its parts, (3). Evidence which skipping phenomenon is occured, during development through zoea larvae to post larvae, couldn't confirm.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.32 no.3
• /
• pp.139-153
• /
• 2014

This study contemplates the utopian landscape recognized by the scholars with twenty three pieces of 'travel record'. Consequently, five key words - Mureungdowon(武陵桃源), Byeolcheonji(別天地), Dongcheon(洞天), Chonghakdong, Eungeoji(hermitage) - are chosen for comprehending the utopia and their landscape characteristics are organised as follows. Mureungdowon in Jirisan Mountain which the scholars dreamed of is a flatland with the full energy for local vegetation and domestic animals in the mysterious and deep gorge. This utopia eventually reflects the rural landscape. Byeolcheonji is a utopia combining the concept of a fairyland and beautiful scenery. The scholars also used the term 'Dongcheon' for naming the enclosed landform which is suitable for seclusion and defining the some areas of beautiful scenery. Cheonghakdong, which is set only in Jirisan Mountain, has been formed by the stone scenery of gorges and Buril waterfalls around the whole area of Burilam Hermitage, the vegetation scenery of pine trees and bamboos with the legend of Choi Chiwon and his engraved inscription on a rock. Adding to the utopia passed down, the scholars perceived the village with geographical features with back to the mountain and facing the water, the river practising the trade, the flatland enclosed by bamboo forests, the vegetation mainly consisting of fruit trees and beautiful scenery as the utopia realized on earth. It is equivalent to the world of human beings laboring appropriately and living in Mother Nature. As mentioned above, this study has significance for apprehending the relevance between the culture of strolling in the mountains by the scholars of Joseon Dynasty and the fairyland and explaining the various traditional utopias from the inherited concepts from China to the naturalized realistic utopia.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.32 no.3
• /
• pp.121-129
• /
• 2014

This study was carried out to research the locations and comprehensive functions of Chinese unique Banwoldang(half-moon shaped pond) appeared at the traditional Chinese villages. Based on the research, the time of Banwoldang being introduced into Chinese traditional culture could date back to Yuan Dynasty and villages that have Banwoldang mainly distributed in the south of the Yangtze River of China where wealthy and high class have lived. Bamwoldangs were mostly built at the front of the village clan halls for the prosperity of the whole clan, The main reason of Banwoldang construction was to complete Feng Shui functions and its goal from the point of Feng Shui in Chinese ancient villages was replenishing the power of location, including increasing the probability of passing the imperial examination for villagers, multiplying riches, minimizing the fire accident and perfecting the geomantic pattern 'leaning against the hill and facing the water(背山臨水)' of villages. Other functions of Banwoldang were found as the place for the community meeting, fish farming and protection of village from enemy. In this research, the reasons of Banwoldang location and values of its various functions were found. But Banwoldang is disappearing rapidly at the Chinese modern villages because there is no interest in traditional culture. Banwoldang is one of unique elements of Chinese culture that must be preserved, so its meaning and value should be lasted well as the Chinese traditional cultures.