• ALGAE
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• v.38 no.1
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• pp.57-70
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• 2023

The mortality rate of red-tide dinoflagellates owing to predation is a major parameter that affects their population dynamics. The dinoflagellates Ansanella granifera and Ansanella sp. occasionally cause red tides. To understand the interactions between common heterotrophic protists and A. granifera, we explored the feeding occurrence of nine heterotrophic protists on A. granifera and the growth and ingestion rates of the heterotrophic dinoflagellate Gyrodinium dominans on A. granifera as a function of prey concentration and those of Oxyrrhis marina at a single high prey concentration. The heterotrophic dinoflagellates Aduncodinium glandula, G. dominans, Gyrodinium moestrupii, Luciella masanensis, Oblea rotunda, O. marina, Polykrikos kofoidii, and Pfiesteria piscicida and the naked ciliate Strombidium sp. were able to feed on A. granifera. With increasing mean prey concentrations, the growth and ingestion rates of G. dominans feeding on A. granifera rapidly increased and became saturated or slowly increased. The maximum growth and ingestion rates of G. dominans on A. granifera were 0.305 d^-1 and 0.42 ng C predator^-1 d^-1 (3.8 cells predator^-1 d^-1), respectively. Furthermore, the growth and ingestion rates of O. marina on A. granifera at 1,700 ng C mL^-1 (15,454 cells mL^-1) were 0.037 d^-1 and 0.19 ng C predator^-1 d^-1 (1.7 cells predator^-1 d^-1), respectively. The growth and ingestion rates of G. dominans and O. marina feeding on A. granifera were almost the lowest among those on the dinoflagellate prey species. Therefore, G. dominans and O. marina may prefer A. granifera less than other dinoflagellate prey species. The low mortality rate of A. granifera may positively affect its bloom formation.

• Journal of Korean Neurosurgical Society
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• v.49 no.1
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• pp.20-25
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• 2011

Objective: Due to longer life spans, patients newly diagnosed with unruptured intracranial aneurysms (UIAs) are increasing in number. This study aimed to evaluate how management of UIAs in patients age 65 years and older affects the clinical outcomes and post-procedural morbidity rates in these patients. Methods: We retrospectively reviewed 109 patients harboring 136 aneurysms across 12 years, between 1997 and 2009, at our institute. We obtained the following data from all patients: age, sex, location and size of the aneurysm(s), presence of symptoms, risk factors for stroke, treatment modality, and postoperative 1-year morbidity and mortality. We classified these patients into three groups: Group A (surgical clipping), Group B (coil embolization), and Group C (observation only). Results: Among the 109 patients, 56 (51.4%) underwent clipping treatment, 25 (23%) patients were treated with coiling, and 28 observation only. The overall morbidity and mortality rates were 2.46% and 0%, respectively. The morbidity rate was 1.78% for Clipping and 4% for coiling. Factors such as hypertension, diabetes mellitus, hypercholesterolemia, smoking, and family history of stroke were correlated with unfavorable outcomes. Two in the observation group refused follow-up and died of intracranial ruptured aneurysms. The observation group had a 7% mortality rate. Conclusion: Our results show acceptable favorable outcome of treatment-related morbidity comparing with the natural history of unruptured cerebral aneurysm. Surgical clipping did not lead to inferior outcomes in our study, although coil embolization is generally more popular for treating elderly patients, In the treatment of patients more than 65 years old, age is not the limiting factor.

• The Korean Journal of Ecology
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• v.15 no.1
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• pp.19-33
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• 1992

The density, litterfall, phytomass, and primary productivity for 7 years in quercus mongolian forest locasted at mt. nambyengsan, pyeongchang-gun, gangwon provance in central part of korean peninsula were estimated quantitatively. at the first year in 1984, a stand had 1, 450 trees/ha in tree density, which was 0.67 of skewness and 0.54 of kurtosis in frequency distribution, however, at the 7th year in 1990, the stand had 1, 133 trees/ha in the density with 22%(or 316 tree/ha)in mortality, which was 1.16 of skewness and 1.89 of kurtosis in the frequency. annual mean litterfall was 5 ton DM/ha, which was composed of 68% of leaves, 17% of branches, 3% of bud scales, 9% of arcons and cups, 0.7% of flowers and others. the phytomass of tree layer for 7 years was gradually increased from 149.7 ton DM/ha at the first year to 188.5 ton DM/ha at the 7th year.annual net productivity for the tree layer studied ranged from 8.76 ton DM/ha.yr-1 to 11.62 ton DM/ha. yr-1 with heavy fluctuation year by year. average annual productivity of the stand of trunk, branches, leaves and roots for 7 years were 4.42, 0.67, 3.85 and 1.29 ton DM/ha.yr-1, respectively. turnover rate of the stand was 6.9% at the first year and 5.6% at the 7th year. such fluctuation of the productivity was caused by the chang of density, mortality, mortality and turnover rate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.686-695
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• 2002

Samples of Corbicula ( Corbicula) japonica Prime of Namdae Stream in Gangnung were collected from November 2000 to October 2001. Age of C. (C.) japonica was determined from the rings on the shell, The shell length of the samples ranged from 8 mm to 38 mm. The ring on the shell was formed once a year in March. Von Bertalanffy's growth parameters were estimated using a nonlinear regression method, asyinptotie shell length ($L_{\omega}$) was 48,98 mm, K was 0.20421year, theoretical age at 0 shell length $(t_0)$ was 0.3169 year, and asymptotic total weight ($W_{\omega}$) was 41.37 g. The formula of allomeky between shell length (L, mm) and total weight (W, g) of the brackish water clam was W=3.42$\times$10^{-4}L^{3}. The annual survival rate was estimated at 0.3799, instantaneous coefficient of natural mortality was 0.5007/year, and instantaneous coefficient of fishing mortality was 0.46721year. The age at first capture was estimated at 2.1593 year using shell length compositions of the brackish water clam, The current yield-per-recruit at 0.4672/year of fishing mortality was 0.6595 g. F_0.1 was estimated at 0.1865/year, Acceptable biological catch was estimated at 14.4 metric ton.

• Journal of fish pathology
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• v.34 no.1
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• pp.99-104
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• 2021

In this study, we investigated safety and efficacy of a low temperature immunization protocol with NNV in red spotted grouper, Epinephelus akaara and long tooth grouper, Epinephelus bruneus and seven band grouper, Hyporthodus septemfasciatus. Further, growth rate between immunized and naïve fish was evaluated during the experiment to check side effect of immunization. Three grouper species were immunized by immersion method with live NNV at 10^5.0 TCID₅₀/mL at 16.5℃ for 30 min and reared for 120 days at natural sea water temperature. To evaluate growth rate, total length and wet weight was measured 7 times after immunization. Immunized three grouper species were challenged by intramuscular inoculation with NNV at 10^4.2 TCID₅₀/100 µL/fish. Immunization at low temperature with live NNV did not show any clinical symptoms of infection, mortality and inhibition of growth. After challenge, cumulative mortality of naïve seven band grouper, red spotted grouper, long tooth grouper were 45, 10, 20 %, respectively. However no mortality was observed at immunized groupers. Thus, it was demonstrated that immunization at low temperature with live NNV are able to protect three different species of groupers without inhibition of growth.

• Environmental Analysis Health and Toxicology
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• v.17 no.3
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• pp.219-224
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• 2002

This study was carried out to examine the effects of bis (tribytyltin)oxide (TBT), endocrine disrupting compounds (EDCs). on the changes of survival, growth and oxygen consumption rate in the oliver flounder, Paralichthys olivaceus. Oliver Flounders were exposed to sublethal concentration of TBT (0, 1.67, 3.20, 6.30 and 12.50 $\mu\textrm{g}$/L) during 6 weeks. Survival rate was decreased in a concentration and exposure period-dependent way and suddenly the reduction of more than 20% occurred at TBT concentration greater than 3.20 $\mu\textrm{g}$/L. after exposure 6 weeks. Growth rate and feed efficiency significantly decreased at concentration greater than 3.20 $\mu\textrm{g}$/L. Oxygen consumption rate was also decreased in a concentration-dependent way and significantly decreased to 17,48 and 67％ than that of the control at the TBT concentration of 3.20, 6.32 and 12.50 $\mu\textrm{g}$/L, respectively. This study revealed that high TBT concentration ($\geq$3.20 $\mu\textrm{g}$/L) reduced growth and oxygen consumption rates of the juvenile oliver flounder suggesting potential influence on the natural mortality of Paralichthys olivaceus in the coastal areas.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.215-219
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• 2010

The objective of this study was to examine the reproductive characteristics of cloned miniature piglets produced from surrogate domestic pigs. Somatic cell nuclear transfer (SCNT) miniature pig embryos were transferred into domestic pigs. As controls, domestic pigs of the same breed with surrogates for SCNT embryos and miniature pigs of the same breed with the somatic cell donor were bred by artificial insemination and natural mating, respectively. Surrogate domestic pigs that farrowed cloned miniature piglets had a significantly longer gestation length (118.1 days) than conventionally bred domestic (115.4 days) and miniature (115.5 days) pigs. Furthermore, the birth weight of cloned miniature piglets produced from domestic pigs (743 g) was significantly greater than that of miniature piglets produced by natural breeding (623 g). Also, cloned miniature piglets had a significantly lower weaning rate (49.7%) than conventionally produced domestic (91.5%) and miniature (100%) piglets. No differences were observed between female and male cloned piglets in gestation length, litter size, birth weight, or weaning rate. Our results demonstrate that gestation length is extended in domestic pigs that are transferred with SCNT miniature pig embryos and that cloned miniature piglets have increased birth weight and high pre-weaning mortality.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.375-376
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• 2000

Sex ratio of a population is a key factor to determine reproductive rate of the population. If the population has skewed sex ratio to the male, the population size may decline gradually at an area which it inhabits, and, furthermore, if a species plays an ecologically important role in its community (e.g., a keystone species in Paine, 1966), its potential reproductive rate will be to form a characterized community because community structure is strongly influenced by the abundance of the ecologically important species (Hughes, 1986). A number of workers (e.g., Bryan et al., 1986 in Nucella lapillus; Spence et al., 1990 in Thais haemastoma) suggested that high frequency and/or late stage of imposex might affect the female mortality and normal reproduction adversely. Consequently, the imposex could affect sex ratio of natural population of some neogastropod including thaisid species. (omitted)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.6
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• pp.475-483
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• 1990

An assessment of Kuwait's commercial fish stocks: hamoor (Epinephelus tauvina), zobaidy (Pampus argenteus), nakroor (Pomadasys argenteus) and sheiry (Lethrinus nebulosus), was conducted using length-frequency data, mean growth and mortality estimates obtained during 1981$\~$1988. The length-cohort analysis indicated that increases in fishing effort would not lead to long-term gains in yield of the stocks at the current estimate of natural mortality rate (M). At high M which was assumed arbitrarily, some benefit in yield could be obtained, especially for hamoor and sheiry. At low M, the yield of all stocks decreased with increased fishing effort. Increases in fishing effort resulted in significant dec-line in spawning stock size for all the stocks. Yield-per-recruit analysis indicated that, un-der low M assumption, a higher yield can be obtained for zobaidy and nakroor by reducing fishing effort. At moderate M, decreases in fishing effort brought gains in yield per recruit of the stocks, but it was not substantial compared with the present level of M. At high M, most of the stocks reached the maximum yield-per-recruit. Overall, increased fishing effort either will not be associated with large long-term gains in yield or, in some stocks, might cause a decline from the present level.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.493-498
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• 2012

We derived biological reference points for Pacific cod Gadus macrocephalus in southeastern Korean waters by applying a yield-per-recruit analysis based on a daily simulation that adopted size-dependent fecundity, growth, and natural mortality functions. This showed that the yield per recruit of Pacific cod can be maximized at an instantaneous rate of fishing mortality (F)=0.37 $yr^{-1}$ under the current regulations, where the minimum catch size ($L_c$)=30 cm in total length (TL). The maximum economic yield was estimated to be attained at $L_c$=35-45 cm TL, if F>1 $yr^{-1}$ but at $L_c$=35-40 cm TL, if F<1 $yr^{-1}$. Despite great uncertainty in the stock assessment, to develop fisheries management plans for the sustainable exploitation of Pacific cod in southeastern Korean waters, it is necessary to estimate F using capture-recapture or other expedient methods.