• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.2
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• pp.102-119
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• 2004

This study investigates the relation between the location of a habitat and the ecological connections according to the habitat type in the riparian zone at the Bokha stream. Stream habitat is classified into nine types for the aquatic insects and fish. For vegetation and birds, habitat is classified into five types of medium-scale streams, including both physical and chemical streams are analyzed accordingly. The major results of this study are as follows: 1) A pool connected to the main stream has a certain water depth (about 80 cm) and is disturbed at least 5 to 6 times a year. Although the pool has a somewhat bad water quality, it provides a habitat for various types of young fish. 2) A meander riffle is about 15 cm deep, the flow velocity in the region is about 75 cm/s. This region does not have large structures to which aquatic insects can attach, so it cannot be used as a spawning ground. 3) A rock type pool is about 60 cm deep, the flow velocity in the meander riffle is about 25 cm/s. In this region, many aquatic insects attached to large structures appear. Due to various riparian vegetation, the rock type pool is used as a habitat for aquatic insects. 4) A pool which is only connected to the main stream during floods has a bad water quality. Despite of its relatively small size, it has a high population density of aquatic insects. faculty.

• Parasites, Hosts and Diseases
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• v.54 no.5
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• pp.617-623
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• 2016

An excavation of the Vesakoyakha II-IV and Nyamboyto I burial grounds was conducted during the 2014 field season, and soil samples from intact burials dating from the 19th and 20th centuries, respectively, were analyzed to determine interactions between parasites and host/vectors. Considering the discovery of Diphyllobothrium sp. and Taenia sp. eggs in soil samples from the pelvic region, diphyllobothriasis was the most frequent helminthic infection among the Taz Nenets. The Nyamboyto Nenets mainly consumed uncooked fish, while the Vesakoyakha Nenets had a bigger variety in food choices, including reindeer meat. Nenets children were given raw fish from early childhood. The paleoparasitological results corroborate rare ethnographic records about the consumption of uncooked reindeer cerebrum which led to beef tapeworm helminthiases. This is the first parasitological report of helminthic diseases among the Taz Nenets, and, as such, it provides insight into their subsistence activities and food patterns and broadens our understanding of their health condition.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.134-142
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• 2017

Nando Island is reported as one of the biggest breeding colonies of seabirds in South Korea, and is protected as a Natural Monument. This study was conducted between July to November 2015, to investigate the breeding population of Black-tailed gulls and their habitat on Nando Island. We estimated the breeding population of Black-tailed gulls (Larus crassirostris) using nest density. The mean nest density of Black-tailed gulls was $0.51\;per\;1m^2$ ($0.51m^{-2}$), and the breeding population was approximately 26,760 individuals. The dominant vegetation was Echinochloa crusgalli and Agropyron tsukushiense var. transiens, which served as shelter and nest sites to Black-tailed gulls. The diet of Black-tailed gulls was mainly the fish, Japanese Anchovy Engraulis japonicas (48%). Other species which were found to breed on Nando Island were Streaked Sheawater (Calonectris leucomelas), Temminck's Cormorant (Phalacrocorax capillatus), and Swinhoe's storm petrels(Oceanodroma monorhis).

• Development and Reproduction
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• v.16 no.4
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• pp.309-314
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• 2012

This study was conducted to analyze the difference of body types within and between wild and farmed populations of olive flounder Paralichthys olivaceus using measured records of morphological traits. The results showed that surveyed traits and standard deviation were $1,355{\pm}742g$ of body weight, $48.01{\pm}7.79cm$ of total length, and $40.96{\pm}6.80cm$ of body length. Also body height, body shape index and condition factor were $17.19{\pm}3.43cm$, $9.99{\pm}0.74$ and $11.16{\pm}1.54$, respectively. As result of least squares mean and standard error for each trait assumed in this study, those of farmed population showed significantly higher than those of wild population in all traits, exclusively in total length and body length (p<0.01). Particularly, the values of the body height and the body weight of the farmed population were higher than those of the wild population in the same total length. And the phenotypic correlation coefficients of the body weight, the total length, the body length and the body height showed strong positive correlation in all populations. These result suggested that morphological differences exist in farmed and wild flounder. Therefore, introduction of wild flounder is essential for the future production to improve the body type of farmed flounder, and parental fish should be chosen by considering selection of commercially important traits in the production process.

• Fisheries and Aquatic Sciences
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• v.27 no.7
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• pp.421-433
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• 2024

Among larger species of fish found in Punatsang chhu, Brown trout (Salmo trutta) and Snow trout (Schizothorax richardsonii) are notable species. Snow trout is a native species, whereas Brown trout is an introduced species. Brown trout is noted to have a negative impact on the population of native species worldwide. This study studied the population dynamics and structure of these species to detect if the introduced species affected the native species adversely. The study was conducted on a 30 km stretch of Punatsang chhu including its major and minor tributaries at about their confluences. In total, 56 sample plots of a 200 m sampling stretch were studied with a 200 m distance between each stretch. Length, weight, maturity, and sex data for both species were collected along with the habitat and water parameters. The two species were found to prefer different areas within a single stretch with a rare overlap. Snow trout were found to be distributed widely within the basin whereas Brown trout were only found in altitudes higher than 1,000 masl ($\overline{x}$ = 1,231.77) and in turbid waters (p = 0.009). Recruitment of Snow trout was not good whereas recruitment of Brown trout was good. Length-frequency graphs indicated good inverse J distribution for the Snow trout population and sporadic for Brown trout. There is an effect of Brown trout introduction to the Snow trout living in the study area. Places invaded by Brown trout have a lesser presence of Snow trout compared to places not invaded by these species.

• Journal of Aquaculture
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• v.21 no.4
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• pp.304-308
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• 2008

Strength of juvenile black seabream (Acanthopagrus schlegeli) produced in the different types of hatchery for wild stock enhancement was evaluated in terms of resistances against anesthetizing agent, tricaine methane sulfonate (MS-222), and dry exposure. The working dosages of MS-222 varied significantly with two different water temperature and hatchery populations. Namely, water temperature $22^{\circ}C$ populations were less resistant against the chemical over water temperature $12^{\circ}C$ ones. MS-222 effects also differed with the fish with different growth histories. The fish seeds in collected from wild showed stronger resistances, earlier recoveries, and lower mortalities, compared to those cultured in land-based tank. Similar results were achieved in the juveniles challenged to dry exposure. These results suggest that wild population of black seabream are more resistant against anesthetic stress, expressed as anesthesia, recovery, and mortality, and further that the population are "healthier" than others.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.5 no.2
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• pp.45-49
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• 1972

The following are some results obtained from a series of experiments in rotifer culture and its usage for the food of tiny fish fry: 1, Outdoor concrete ponds, each being $16m^2$, were used to culture the rotifers, Brachionus calyciflorus, and Filinia longiseta. Brachionus calyciflorus usually attained the population of about 100 individuals per ml of pond water. Dipterex was usually applied to control Daphni,a and other crustaceans that generally appear and feed on rotifers. A concentration of 0.16 to 0.2 ppm in the pond water was sufficiently effective to control these natural enimies of rotifers. Poultry dung was very effectively used to multiplicate rotifers. The fertilization ratio was about 8 kg each pond with 30cm depth of water. 2. The tiny rotifer, Filinia longiseta attained a very high population density of about 1,000 individuals per ml of pond water, but they were very sensitive to dipterex, and for this aspect future investigation may be needed. 3. In the outdoor ponds, the multiplication of rotifers significantly decreased when the water temperature falls to about $20^{\circ}C$ in autumn. 4. In the laboratory room, unicellular planktonic algae such as Scenedesmus or Chlorella, as the food of rotifers, were collected from the outdoor ponds by dipping them together with water, and were effectively used for the culture of Brachionus calyciflorus. If the planktonic algae are cultured in specially designed containers, the sun-light would be the most effective means as the source of light. 5. Brachionus calyciflorus cultured in the outdoor ponds by the dipterex controlled method was highly efficient to rear the early fry of marble gourami. The dipterex content mixed in the water to control the crustacean emmies of rotifers sieved no harm to the gourami fish fry.

• Korean Journal of Ichthyology
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• v.20 no.4
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• pp.248-254
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• 2008

Olive flounder (Paralichthys olivaceus) is one of the most popular farmed fish in Korea. Genetic variability of the fish was investigated by means of microsatellite DNA markers. All of the 8 microsatellite loci were analyzed in this study. For the confirmation of genetic variation during a shift in generation, microsatellite variability was compared within the same hatchery strains but produced in different spawning years. When genetic variability of farmed flounders produced in 2006 and 2007 was compared with that of 2003, a marked reduction of genetic variability was observed in the 2006 and 2007 populations. Mean number of alleles per locus and expected mean heterozygosity decreased from 9.75 and 0.796 (in 2003 population) to 7.78 and 0.785 (in 2006 population), respectively. Moreover, we have observed the distortion of allele frequency. These results show that reduced genetic variability of farmed olive flounder in processed generation has lower numbers of alleles and genetic variability than these of wild fish. Our results suggest that to have a sustainable aquaculture of this species, there is need for scientific broodstock management based on genetic variation and more intensive breeding practices to improve genetic diversity and to avoid detrimental inbreeding effects.

• Ecology and Resilient Infrastructure
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• v.2 no.3
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• pp.216-223
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• 2015

The conservation project to protect an endangered fish, Gobiobotia naktongensis was executed against declining the gene diversity of the fish after the construction of Youngju Dam in a sand-bed stream (Naeseongcheon Stream). We tried to move the populations of G. naktongensis from submerged planned sites to alternative habitats, bred artificially and augmented the juveniles to optimal habitat, and monitored the results of the restoration implementation. No entity of G. naktongensis was confirmed at the planned submerged sites despite attempting to capture more than 8 times and eventually the movement to alternative habitat could not be implemented. About 40 individuals of G. naktongensis were captured in the Naeseongcheon Stream and a total of 5,000 individuals were artificially spawned up. The population of juvenile inherited the genetic diversity from the brood stock. The bred juveniles were discharged at the selected optimal site that had a habit condition what was similar to their natural habitat. The micro-dispersion around the discharging area was found at the early stages of the augmentation. The re-capturing rate of discharged juveniles was reduced as time passed. The discharged juveniles seemed to adapt to the natural environment of Naeseongcheon Stream. The observation of their high abdominal distension and excrement demonstrated that the juveniles fed successfully in the discharging area. Therefore, securement of genetic homogeneity and enhancement of restoration population of G. naktongensis in upstream and downstream of Youngju Dam site from the artificial seed producing seemed to be primarily successful and long-term monitoring and analysis of the effect was expected to be necessary.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.375-383
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• 2023

To determine the cause of the population decline in Gobiobotia naktongensis, substrate preference and burying behaviour were investigated in this study. In general, the species was shown to prefer a substrate size of 1 mm or less, depending on the flow. In addition, the burying depth varied according to the size of the fish and increased with a decrease in water temperature. Our findings showed that the main cause of the population reduction was the physical changes in the substrate structure due to the dams or barrages construction. Notably, the accumulation of silt and mud in the substrate upon the formation of an upstream lentic water region for structural construction and bed armouring caused by scouring and reduced downstream inflow of fine sediment were deterministic in the fish habitat changes, causing problems in burying. As sand substrate structure is critical for the survival and inhabitation of psammophilous species, efficient strategies should be developed with proper habitat management to reduce the anthropogenic damage