• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.39 no.1
• /
• pp.56-62
• /
• 2003

To investigate the entrapping behavior of blue crab, rock shell and green ling, which are mainly caught with the other trap nets in the coastal area of Yellow Sea, by the using duration of trap nets through the water tank experiment. We select the three kinds of trap nets which have different using duration such as new, 6 months and 12 months used one, and observe the entrapping ratio into the trap nets, respectively. In the mean while, in order to obtain the basic data for the estimate of mesh selectivity of the other trap nets, the entrapping behavior into the trap nets for green ling which has high activity compared to blue crab and rock shell, are examined to the three kinds of mesh size (35mm, 50mm and 65mm). The results are as follows ; 1. The mean entrapping ratio of blue crab by the using duration of trap nets in high with 4.4 fishes (44.0%) in the 6 months used one, become lower with 2.9 fishes (28.0%) in the new one, and with 2.0 fishes (20.0%) in the 12 months used one. 2. The mean entrapping ratio of rock shell by the using duration of trap nets in high with 7.3 fishes (36.7%) in the new one, and become lower with 7.2 fishes (35.8%) in the 6 months used one, and with 5.7 fishes (28.3%) in the 12 months used one. 3. The mean entrapping ratio of green ling by the using duration of trap nets in high with 3.4 fishes (34.0%) in the 6 months used one, and become lower with 3.0 fishes (30.0%) in the new one, and with 2.8 fishes (28.0%) in the 12 months used one. 4. The mean residual ratio of green ling by the mesh size of trap nets is high with 2.4 fishes (24.0%) in the 35mm mesh size, and become lower with 2.2 fishes (22.0%) in the 50mm mesh size and 2.0 fishes (20.0%) in the 65mm mesh size.

• Journal of fish pathology
• /
• v.22 no.3
• /
• pp.293-303
• /
• 2009

Effects of stress on the low salinity stress were examined in the pacific abalone Haliotis discus discus. Changes in survival rate, hemolymph count, antioxidant enzyme activities (catalase: CAT and superoxide dismutase: SOD), respiratory burst activity, phenoloxidase activity, lysozyme activity and expression of heat shock protein 70 (HSP70) mRNA were measured 0, 3, 6, 12, 24 or 48hours after low salinity treatment with 25, 30, 33 and 35 psu. Survival rates of pacific abalone were 100% at 33 and 35 psu, but 93 and 97% at 25 and 30 psu for 48 hours, respectively. Hemolymph counts decreased in the time elapsed-dependent way at all of the experimental groups. At low salinity, 25 and 30 psu, SOD and CAT activity increased compared to the experimental group of 33 psu. Moreover, respiratory burst activities of the pacific abalone seemed to have no effect on low salinity stress at any experimental group. However, phenoloxidase activity is an important component of the defence against pathogen that was decreased in a reduction of salinity dependent way. Lysozyme activity also immediately reduced at 25 psu experimental group for 48 h. The HSP70 mRNA was weakly expressed at 33 psu, but strongly detectable at 25 psu experimental group. The HSP 70 mRNA expression in gill increased in the time elapsed-dependent way at 25 psu experimental group and then recovered at 48 h. These results suggest that low salinity stress give rise to inhibitory action of immune system as a result of the decrease of phenoloxidase and lysozyme activity in the pacific abalone, especially.

• Journal of fish pathology
• /
• v.2 no.1
• /
• pp.1-18
• /
• 1989

In Korea, studies on a Nematode, Anguillicola crassa parasitic in the air bladder of eel are not yet reported. This reason led the author to study the parasitic species, state and life history of the A. crassa parasitized in the air bladder of eel in order to take effective control measures against its damage. The size of fully developed eggs was 80 to $92(86.7){\times}62$ to $71(67.4)\;{\mu}m$, larva was 210 to $240(225){\times}18$ to $23(20.6)\;{\mu}m$. The intermediate host of A. crassa was Thermocyclops hyalinus, it was capable for parasitizing the eel after 4 days of invasion and then the size of larva was 360 to $420(390){\times}28$ to $35(31)\;{\mu}m$. Fifty days after eel had ingested the Thermocyclops hyalinus infected with larva of A. crassa, the larvae matured into adult worms in the air bladder of eel. The size of detected adult worms was 7.3 to $31.0(16.5){\times}0.5$ to 2.2(1.2) mm, 4.9 to $13.3(8.3){\times}0.3$ to 0.9(0.4) mm. Investigating the morphology of the worms, they were identified as A. crassa. Monthly the parasitic rate of the worms in the eel was high in June, September and December, but low in January to March. After the investigation on the significance between non-parasitic fish and parasitic fish, it was not significant, therefore it can be considered that there is no effect of infection in the growth of eel. Any abnormality of eels air bladder tissue was not seen by the infection of A. crassa. At 25.0 to $26.7^{\circ}C$ of water temperature the death time of Thermocyclops hyalinus by masoten treatment was 14 hours in 0.5 ppm, 20 hours in 0.4 ppm, 22 hours in 0.3 ppm, 30 hours in 0.2 ppm and 42 hours in 0.1 ppm.

• Journal of fish pathology
• /
• v.2 no.2
• /
• pp.53-70
• /
• 1989

An ovarian parasite, Marteilioides chungmuensis of the Pacific oyster, Crassostrea gigas has been observed on several occasions in the Pacific sector of production of this oyster species(Matsuzato et al., 1977 ; Chun, 1979). This study was carried out on the specimens collected at Hwado, Och'$\check{o}$n, and Sinchang respectively located the southern, western, and eastern coasts of Korean Peninsula from 1986 through 1988 to investigate M. chungmuensis to the Pacific oyster. Uitrastructural studies were also carried out on infected oysters, to allow detailed examination of the structure and consepuently the systematic position of this parasite. Infection rates of M. chungmuensis at Hwado and Och'$\check{o}$n oyster farms were 5.3% and 4.2% each in 1986, 6.7% and 2.8% each in 1987, but they were not found at Sinchang oyster habitat. M,. chungmuensis-infected oysters were found from June to November at Hwado and from June to October at Och'$\check{o}$n. Twenty five of three hundred oysters transplanted from Sinchang to Hwado were found infected with M. chungmuensis. Some abnormal eggs infected with M. chungmuensis are liberated through the gill together with normal mature eggs on the spawning and the rest remain necrotized after spawning season. The earliest known stages consist of a stem cell or primary cell, including a secondary cell in which ovoid haplosporosomes are found. During sporulation, 2 or 3 secondary are produced by exogenous budding from the first secondary cell and, each secondary cell evolves into a sporont upon the tertiary cell differentiation (enodogenous budding) ; then, haplosporosomes are formed in the young sporont. Internal cleavages involve the differentiation of one tricellular spore per sporont. The outermost spore cell contains membrane-bounded osmiophilic bodies : the middle and the inner, most spore cells contain high density cytoplasmic ribosomes. The mechanism of spore formation from the stem cell of M. chungmuensis is the simplest of the class Paramyxea known up to now.

• Radiation Oncology Journal
• /
• v.15 no.4
• /
• pp.305-313
• /
• 1997

Purpose : This is a retrospective study to evaluate the results of radiation therapy and prognostic factors influencing the results in nasopharyngeal carcinoma. Materials and Methods: From October 1989 to May 1996. 56 Patients were treated for nasopharyngeal carcinoma at Department of Radiation On-cology. According to stage, patients were distributed as follows : stage I (2), II (13). II (11), IV (30). Twenty-eight patients were treated with radiation therapy only, 7 patients were treated with neoadiuvant chemotherapy followed by radiation therapy. Twenty-one Patients were treated with radiation therapy and weekly CDDP. After external beam radiotherapy of 60Gy, 46Patients received boost dose with intracavitary radiation and 9 Patients with 3D conformal therapy. One patient received boost dose with 2 dimensional Photon beam therapy. The tumor dose ranged from 69.4Gy to 86.2Gy with median dose of 74.4Gy. The follow-up Period ranged from 5 months to 92 months with a median of 34 months. Results : Forty-seven patients achieved complete response and 8 Patients showed partial response. One Patient showed minimal response. Patterns of failure were as follows : locoregional recurrence (8) and distant metastasis (18). Among these patients, 2 patients failed locoregionally and distantly. The sites of distant metastasis were bone (8), lung (8) and liver (4). Five years survival rate was $67.2\%$ and 5 years disease-free survival rate was $53.6\%$. KPS (P=0.005) and response ol radiation therapy (P=0.0001) were significant prognostic factors for overall survival. KPS (P= 0.02) and response of radiation therapy (P=0.005) were significant Prognostic factors for disease-free survival. Conclusion : This retrospective study showed that distant metastasis was the Predominant pattern of relapse in nasopharyngeal cancer Neoadiuvant chemotherapy or weekly CDOP did not influence the distant metastasis-free survival. For advanced T stage, 3D conformal therapy Provided an improved dose coverage compared to ICR But further follow-up was needed in Patients with 3D conformal therapy to assess the efficacy of this therapy. Development of techniques of radiation therapy to improve locoregional control and of more effective systemic chemotherapy regimen are needed.

• Korean Journal of Environmental Biology
• /
• v.23 no.3 s.59
• /
• pp.293-303
• /
• 2005

Japanese medaka, Oryzias latipes is widely distributed in the North East Asia including Korea, Japan and east China, and commonly used for freshwater toxicity tests and cytotoxicological studies worldwide. In this study, a series of experiments were conducted to identify the potential of the fish as a standard test species for saltwater toxicity evaluation such as marine receiving waters, ocean-dumped materials and sediment pore waters etc. Hatching, growth and mortality rates of the fish were estimated with the wide ranges of salinity from freshwater to seawater (35 psu). Direct exposure of the fertilized eggs in freshwater to the wide ranges of salinity (from 0 to 35 psu) without pre- acclimation to the saltwater revealed no significant differences in hatching rates by salinities (p =0.24). On the other hand, medaka larvae hatched in freshwater and exposed to saltwater directly showed high mortality at > 25 psu treatment groups (p < 0.0001). However, there was no significant difference in mortality of medaka larvae hatched in 13.8 and 14.2 psu at the wide ranges of salinities ($0\~35$ psu). Growth rates of medaka larvae hatched in the above two salinities showed no differences in body length either from 0 to 35 psu treatment groups (p =0.64 for 13.8 psu group and p=0.32 for 14.2 psu group). The number of gill chloride cell in medaka larvae sharply increased when the larvae were exposed to high salinity. Reference tests with zinc chloride revealed 96h $LC_{50}=8.84(7.19\~10.87)mg\;L^{-1}$ using 7~10 day old medaka larvae. These were comparable or better sensitivity in comparison with the other standard test species such as North American sheepshead minnow Cyprinodon variegatus. Based on the results of these experiments, hatching rates and larvalmortality of medaka must be good toxicity parameters for seawater bioassay and the species seems to be a good standard species for both the freshwater and seawater toxicity test.

• Korean Journal of Environmental Biology
• /
• v.32 no.3
• /
• pp.216-224
• /
• 2014

Decrease in dissolved oxygen concentrations associated with temperature fluctuation is an important criteria to evaluate the mortality rate of the species. Based on this parameter, we investigated the survival rate, physiological response and histological change of warty sea squirt. It was found that the survival rate of the warty sea squirt species was 63.3% at $23^{\circ}C$ and 56.6% at $26^{\circ}C$ respectively. However, exposure of six days at $29^{\circ}C$ caused deaths among species, which indicated the 6day-$LT^{50}$ of the tested species to be $24.58^{\circ}C$ ($19.48{\sim}35.48^{\circ}C$). Further, after 11 day of exposure, the dissolved oxygen concentration has been found to decrease, with the survival rate of 20% at $4.0mg\;L^{-1}$ and deaths at $2.0mg\;L^{-1}$, thus 11day-$LC^{50}$ calculated to be $3.88mg\;L^{-1}$ ($3.29{\sim}4.57mg\;L^{-1}$). In addition, decrease in rate of oxygen consumption and excretion of ammonia was also noted at this critical water temperature and dissolve doxygen concentration. Moreover, there has been common histopathological changes were observed in warty sea squirt's gill pouch, digestive tract, and tunic as follows such as: proliferation of epithelial cells, condensation and necrosis, permeation of phagocyte and blood cell, loss of cilium and muscular fiber degeneration. Based on our study results, we suggest that these parameters can also be useful to evaluate the survival rate and physiological response in other species.

• Journal of fish pathology
• /
• v.3 no.1
• /
• pp.21-25
• /
• 1990

In inland aquaculture, a lot of fishes often died cause of touch of L. carteri which is attached on the net cage. In this works, the experiment were carried out on classification of species, toxin test, and extermination with some chemicals. A bryozoa from net cage in lake Okjeong is classified into the Phylactolaemata, Lophopodella carteri Hyatt. A bryozoa broke out firstly on the 30th of June with water temperature up to $31^{\circ}C$ and it reattached on the net with water temperature below $30^{\circ}C$. Size of bryozoa colony is about $0.8{\times}0.6{\sim}1.7{\times}1.5cm$. Water column of attachment was 0~5m and the peak is 2~3m. In toxin test on the israeli carp, goldfish and catfish touched with bryozoa for 1 minute at $25^{\circ}C$ of water temperature, a dead fish appeared at 20 minutes after touched. Mortality was 90% for israeli carp and 100% for goldfish at 100 minuties after touched, but catfish was not died at all. It was supposed that the toxin is from nematocyst being around tentacles and this toxin act a deadly poison on a israeli carp and goldfish. In extermination test, the bryozoa treated with 300ppm of formalin, 5% of sodium chloride, 5ppm of malachite green, 200ppm of potassium permanganate, 1000ppm of potassium iodide, 10ppm of DDVP for minute respectively, all of them were not effected.

• Korean Journal of Ecology and Environment
• /
• v.41 no.2
• /
• pp.188-197
• /
• 2008

This research was a preliminary case study to determine the levels of total mercury in the tissues of sentinel species (Zacco platypus) and ecological health in relation to habitat characteristics and chemical conditions. We collected fishes in Gap Stream during June$\sim$October 2007 and analyzed the total mercury from five types of tissues such as liver, kidney, gill, vertebrae and muscle of Zaceo platypus using Direct Mercury Analyzer (DMA-80, US EPA Method 7473). Mean concentrations of total [Hg], based on all tissues, was 67.2 and $20.7\;{\mu}g\;kg^{-1}$, in the upstream and downstream site, respectively, indicating 3 times greater level in the upstream. In other words, the levels were higher in the pristine upstream than the downstream influenced by the wastewater disposal plant. Chemical water quality, based on BOD, COD and nutrients (TN, TP) showed that severe degradation occurred in the downstreams than the upstreams. Index of Biological Integrity (IBI) using fish multi-metric model averaged 32, indicating a "good$\sim$fair" condition and varied from 42 (excellent$\sim$good) at S2 to 22 (fair$\sim$poor) at S5 depending on the sites sampled. Qualitative Habitat Evaluation Index (QHEI) in the all sites averaged 142, which was judged as "good" habitat health, but showed a high variation (181 in Site 2 vs. 67 in Site 5). Overall data suggest that health conditions, based on IBI and QHEI, was better in the upstream sites but the mercury bioaccumulation levels in the fish tissues were opposite. We believe that measurements of various parameters are required for a diagnosis of integrative ecosystem health.

• Development and Reproduction
• /
• v.5 no.1
• /
• pp.39-45
• /
• 2001

Black rockfish Sebastes schlegeli is one of scopaenid fish giving birth to yolk-sac larvae and distributed around the coast of Korea and Japan, and is one of main species which is cultured in Korea. The difffrentiation of thyroid gland and the changes of thyroid hormones (THs) concentrations in the whole body during early development of this species were examined and the relationship between thyroid gland and their growth will be presented. Total length (TL) and body weight (BW) of the larva at the parturition were 6.3${\pm}$0.1 mm and 3.6${\pm}$0.1 mg, respectively. The larvae transformed to juvenile after 30th day after parturition. According to Hoshiai(1977), they had gown into stage Fl (TL 13.2${\pm}$0.9 mm, BW 46.5${\pm}$1.5 mg) at 50th day. The thyroid gland of black rockfish was first observed histologically in hatching larvae in mother fish. The larvae just after parturition have 1${\sim}$3 of the thyroid follicles diffrentiated between basibranchial bone and ventral aorta, at the base of the first gill arch. In this time, thyroid follic1e number (TFN),thyroid follicle diameter (TFD) and thyroid cell height (TCH) were 1.6${\pm}$0.8 pieces/inds., 18.1${\pm}$0.6 ${\mu}$m and 4.1${\pm}$0.2 ${\mu}$m, respectively. TFN and TFD at 50th day were increased to 32.5${\pm}$6.9 pieces/inds. and 41.5${\pm}$1.7 ${\mu}$m, respectively. These results indicate that they are related to the growth of black rockfish during early development. However, TCH indicates that the activity of thyroid gland appearedat special day, eg. 5, 20 and 50th day, suggesting that TCH may have some role in the physiological activity. L-thyroxine (T$_4$)concentration decreased sharply to 10 days after parturition, and at 25th day (metamorphosis stage) increased markedly to 3.44${\pm}$0.93ng/g fish. After this time, T$_4$ concentration decreased at 35th day, but then increasedagain to the highest concentration, 5.63${\pm}$0.70ng/g fish. 3,5,3'-triiodo-L-thyronine (T$_3$) concentration declined sharply from just after pafurition (4.96${\pm}$1.90 ng/g fish) to 5th day (0.30${\pm}$0.07 ng/g fish). However T$_3$ concentration increased markedly to 0.95${\pm}$0.11 ng/g fish at 30th day and then did not significantly change until 45th day, increased also sharply to 1.67${\pm}$0.23 ng/g fish at 50th day.