• Korean Journal of Ichthyology
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• v.26 no.2
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• pp.112-117
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• 2014

The spawning behavior, development of eggs and larvae of the blennioid fish, Dictyosoma burgeri were investigated. The blennioid fish were caught at Hwayang-myeon, Yeosu-si, Jeollanam-do from December 2013. The egg was spherical, measuring from 1.31 to 1.47 mm in diameter. The incubation period of the egg extended from 744 hrs at the temperature varying between 14.5 and $16.5^{\circ}C$. The newly hatched larvae were 7.10~7.60 mm(mean $7.34{\pm}0.18mm$) in total length. Two days after hatching, prelarvae was measured 8.43~8.47 mm (mean $8.45{\pm}0.01mm$) in total length. They began to eat rotifer and transformed to postlarvae stage. Six days after hatching, postlarvae was measured 9.06~9.13 mm(mean $9.10{\pm}0.02mm$) in total length.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.222-231
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• 2020

The egg development and early life history of Sharpbelly Hemiculter leucisculus were investigated. For the experiments, the mature adults were collected at the Lake Yedang in Korea. The eggs from the females were obtained by injecting 10 IU/g of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were 0.97±0.02 mm (0.9~1.0 mm n=30) in diameter. The embryo began to hatch about 32 hrs after fertilization under water temperature of 22±1℃. The newly-hatched larvae were 3.0±0.2 mm (2.6~3.4 mm, n=15) in total length, and they haven't Melanophore. Six days after hatching, the Preflexion larva were 5.7±0.1 mm (5.4~5.8 mm, n=15) in total length, and they began to eat a Rotifer. 17 days after hatching, the Flexion larva were 6.8±0.2 mm (6.5~7.0 mm, n=15) in total length, and a gas bladder develop above the intestine. 30 days after hatching, the Postflexion larva were 8.8±0.7 mm (7.9~10.3 mm, n=15) in total length, three dorsal fin rays began to develop in the membrane fins. 50 days after hatching, the Juvenile were 20.8±0.8 mm (18.8~24.6 mm, n=15) in total length, and all their fin-rays were formed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.305-312
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• 1997

Juveniles of black seabream, Acanthopagrus schlegeli were fed with the diets containing 0, 10, 20, 50 and 100 ppm of 3,5,3'-triiodo-1-thyronine $(T_3)$ respectively to assess the effect of this hormone on skeletal development and the change of physiological conditions for 50 days. $(T_3)$ treatment lasted for initial 40 days. Fish were fed the prescribed diet by hand to satiation in $2\~4$ times per day. After an initial 40 days period, skeletal development and abnormality were examined, and after a 50 days period, food intake, hepatosomatic index (HSI), thyroid cell height (TCH) and body proximate composition were also examined. Although toed intake was not different among 0, 10 and 20 ppm, the food intake of black seabream fed with the diets containing 50 and 100 ppm of $T_3$was significantly lower than those of 10 ppm. After the initial 40 days of $T_3$ administration, $T_3$ increased the relative growth of operculum, head, caudal fin and pectoral fin to body length, resulting in severe morphological abnormalities at the highest dose. Black seabream treated with 50 and 100 ppm of $T_3$ had abnormal shapes such as lordosis and opercular curl. The HSI parameters were reversely correlation with the dietary concentration of $T_3$. After the initial 40 days of this experiment, atrophy of thyroid gland was observed in fish administered with 50 and 100 ppm of $T_3$. On the 50th day of this experiment, atrophy of thyroid gland was observed only in the group administered with 100 ppm of $T_3$, and no difference was observed on TCH among the rest fours of experimental groups. At the end of the experiment the whore body proximate analyses indicated that there were significant effects of $T_3$ level on moisture, protein, lipid and ash contents.

• Korean Journal of Environment and Ecology
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• v.26 no.1
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• pp.57-66
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• 2012

This study was conducted to investigate the reproductive ecology of the Korean Mandarin Fish, Siniperca scherzeri in Seomjin River and Imjin River from April to October 2008. After have investigating the relationship between standard length (SL) and Gonadosomatic index (GSI) of Siniperca scherzeri, we can conclude that the body length of maturation was over 200mm SL in case of females and over 180mm SL in males. The GSI of the females that were from Seomjin river was the highest in April (7.43%), and gradually decreased after May (5.55%) and June (3.58%). The GSI was decreased sharply in August and indicated the lowest value in September (0.44%). The GSI of the females that were from Imjin river showed similar tendency of females' GSI from Seomjin river. The GSI of males from Imjin river was totally higher than that of females, it was 5.96% in April, and 8.03% in May. It was lowered in early June, and late June, it indicated 2.12%. In September, it was the lowest value (0.20%), and increased after October (0.54%). The result of histological study of ovary presented similar result of the study of GSI in Seomjin river and Imjin river. The ratio that fishes constitute in stomach contents of Siniperca scherzeri was 92% in Seomjin river and 90% in Imjin river. Digestion of food organisms and the ratio of unidentifiable fishes in stomach contents was fairly high, and it was 50% in Seomjin river and 72.2% in Imjin river. In the period of study, eating ratio was very low 38.3% (36 ind.) in Seomjin river and 21.8 (53 ind.) in Imjin river.

• Journal of Life Science
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• v.28 no.3
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• pp.284-292
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• 2018

The melanin-concentrating hormone (MCH), a cyclic hypothalamic peptide composed of 17 amino acids, was initially identified in chum salmon (Oncorhynchus keta) as a regulator of pigmentation. Mammalian MCHs are cyclic hypothalamic peptides composed of 19 amino acids that regulate food intake and energy homeostasis. The present study examined not only MCH expression of different tissues but also the melanohore aggregation and intracellular $Ca^{2+}$ influx of fMCH and the other MCH. Real-time qPCR showed that MCH expressed specially in the brain, gonad, and ovary, and expression of MCH was observed during the developmental stages. In the application of synthetic fMCH and both types of synthetic fMCH, dN-fMCH and dC-fMCH, scale melanophore induced significant changes in aggregation activity with various concentrations of MCH. Also, compared to hMCH and sMCH, fMCH exhibited a 36~99.85% increase in relative potency (%), whereas aggregation of dN-fMCH and dC-fMCH remained in a high concentration. However, dispersion was induced rapidly according to be low concentration of dN-fMCH and dC-fMCH. We show that fMCH and its derivates were bound human MCHR1 and rat MCHR expressed in HEK293T cells with nano-molar affinity and are likely to be ligand-induced to mobilize intracellular $Ca^{2+}$. These results may provide new ligands for binding assay with MCHew ligands, as a structure similar to the mammalian MCH structure was discovered in fish. Once the fMCH receptor system is in place, it can be compared to the MCH system of mammals in terms of MCH function.

• Korean Journal of Ecology and Environment
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• v.51 no.3
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• pp.234-244
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• 2018

The roadkill that animals die after bumping by vehicles on the roads is acting as a factor to decrease the size of various animal populations. It has also been known to be the biggest artificial causations of Vertebrata deaths not only in urban areas but also protected areas such as national parks. Nevertheless, in the national park areas which are major protected national areas for conservation of national biodiversity and ecological diversity, snake roadkills occur frequently. Up to date, related studies are rare. Therefore, in this study, we described snake roadkill patterns on the roads in six national parks between 2006 and 2015. We identified total 736 snake roadkills compromising 10 different species. Five species, Rhabdophis lateralis, Elaphe dione, Gloydius ussuriensis, Lycodon rufozonatus, Gloydius brevicaudus occupied more than 91.7% of total roadkill cases. Active forager snakes were killed by roadkills more than ambush foragers, and the snake roadkill frequency was the highest in September, a migration period and in August when the young individuals dispersed at between 100 and 799 m altitude areas. Roads where roadkills were frequent lie between forest and hydrosphere or between forest and crop field road sides. Our results could be used to identify the trend of snake roadkills on the roads in national parks, and to establish effective roadkill mitigation measures and policies.

• Applied Microscopy
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• v.42 no.1
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• pp.17-26
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• 2012

Histologic and microstructural changes during the postembryonic development of the wolf spider Arctosa kwangreungensis were studied using light and scanning electron microscopy to examine the relationship between a morphological differentiation and behavioral properties. The postembryo with abdominal yolk sac was stayed inactive in the egg case because its muscular and visual systems were not fully developed to a functional level. The first instar spiderlings, developed from the postembryo by a first molting process, started to exhibit its pigmentation on their body cuticles. In particular, undifferentiated cell clusters of central nervous system (CNS) were densely distributed within the cephalothorax, and highly differentiated abdominal ganglion was observed. They had a characteristic visual system looks more like its adult counterpart, and had segmented appendages looks more like the tiny spiders containing well oriented muscular system. After 3rd instar, spiderlings grew more rapidly with accordance to their consistent growth and periodical molting processes. Thus, the relative area of CNS with respect to cephalothorax was gradually decreased, instead a pair of venom glands, musculature, and connectives occupied the residual area. It has been revealed that the early development of spider can be controled by the feeding condition of larval period, since histologic and microstructural differentiations in both appendages and optic system were completed at the second instar. In particular, behavioral properties of the wandering spiders that depend on vision and their running ability were deeply related to physiological differentiation of the microstructural development.

• Korean Journal of Agricultural Science
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• v.26 no.2
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• pp.13-18
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• 1999

External morphology characteristics of the greenhouse whitefly, Trialeurodes vaporarium were investigated by scanning electron microscopy. The antennae of the greenhouse whitefly was 6 segments. rod-shape, and 0.3mm length. On the 6th segment, there were many sensilla for searching host-plant as olfactory receptor. The mouthpart of the greenhouse whitefly was a piercing-sucing type, then its stylet was well developed for piercing plant leaf tissue. Claw of the foreleg was a 3-way hook shape including paranychium for attaching plant surface to pierce and lay egg.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.281-289
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• 2021

Commercially used disposable cups undergo fragmentation in the environment and become microplastics (MPs). These MPs can be ingested by aquatic organisms and cause a range of adverse effects. We assessed the acute and chronic toxicity of disposable cup-derived MP fragments in Daphnia magna. MP fragments were identified as a polyethylene terephthalate (PET) fragment with a size of 33.18 ± 7.76 ㎛. The presence of three additives including 1- Propanone. 1-phenyl-3-[2-(phenylmethoxy)phenyl]-, p-Xylene and ethylbenzene was analyzed from MP fragments. The 48 h acute toxicity revealed that 20 % of immobilization and mortality were found at the highest concentration of PET MP (200 mg L^-1). The 21 d chronic toxicity revealed that PET MP fragments significantly (p < 0.05) more reduced survival rate (31 %), total offspring (52 %) in D. magna compared with control group. The developmental abnormality of offspring (3.5%) by PET MP fragments was significantly (p < 0.05) higher than control groups (0.3%). These results are possibly induced by gut blocking by ingestion of MP fragments and their longer retention time. These findings indicate that the fragmentation of disposable cups (PET polymers) into small-sized MP fragments pose a significant ecological risk to aquatic organisms. Further studies are required to elucidate the underlying toxicity mechanisms.