• The Korean Journal of Malacology
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• v.29 no.3
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• pp.245-250
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• 2013

We investigated the factors of mass-mortality in terms of water temperature and prey, in order to prevent the mass-mortality of cultured oysters at Gamak Bay in Yeosu City in 2007. The real-time water temperature was recorded as high, 28 to 31C, during late August. Nutrients, Dissolved Inorganic Nitrogen (DIN) and Dissolved Inorganic Phosphate (DIP) were downed in September. The analyzed results of chlorophyll a content were 0.78-1.50 ${\mu}gL^{-1}$ and phytoplankton for food resources was 81 cells $mL^{-1}$, both were low. The finding here indicate that Gamak Bay is in an oligotrophic state. The mass-mortality of cultured oysters occurred 43.6% in Gamak Bay. The mortality rate of oyster were above 67.0%, at Wanpo, however, it was showed 18.3% at Gumchun. Therefore, we believe the mass-mortality of cultured oysters at Gamak Bay comes from the destruction of bio-rhythms due to high water temperature and quantitatively and qualitatively decreasing food resources due to the limitation of nutrients.

• Journal of Ecology and Environment
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• v.45 no.1
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• pp.10-16
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• 2021

Background: Ranavirus is an emerging infectious disease which has been linked to mass mortality events in various amphibian species. In this study, we document the first mass mortality event of an adult population of Dybowski's brown frogs (Rana dybowskii), in 2017, within a mountain valley in South Korea. Results: We confirmed the presence of ranavirus from all collected frogs (n = 22) via PCR and obtained the 500 bp major capsid protein (MCP) sequence from 13 individuals. The identified MCP sequence highly resembled Frog virus 3 (FV3) and was the same haplotype of a previously identified viral sequence collected from Huanren brown frog (R. huanrenensis) tadpoles in South Korea. Human habitat alteration, by recent erosion control works, may be partially responsible for this mass mortality event. Conclusion: We document the first mass mortality event in a wild Korean population of R. dybowskii. We also suggest, to determine if ranavirus infection is a threat to amphibians, government officials and researchers should develop continuous, country-wide, ranavirus monitoring programs of Korean amphibian populations.

• Journal of Environmental Health Sciences
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• v.29 no.4
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• pp.1-3
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• 2003

Jinyangho is a natural water supply source of tap water in west Gyeongnam area, but mass mortality of crusian carp occurred during the time of temperature rise in spring. Examinations on diseased fishes were able to isolate four bacteria isolates and then identified the bacteria as a member of Aeromonas sp. Challenge experiment with mirror carp (Gyrinus carpiospecilaris) was proved the virulence, the isolates were in turn believed as the causative agent of mass mortality in Jinyangho.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.175-182
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• 1999

An unprecedented mass mortality of commercially important macrobenthic animals, including Haliotis discus discus, H. diversicolor, Batilus cornutus, Sticopus japonious and Hemicentrotus puzoherrimus, occurred off the west coast of Cheju Island in summer of 1996. Phytoplankton blooms were absent along the coast. The appearances of the surface low-salinity water (SLSW) off the coast of Cheju Island preceded the mass mortality, leading to speculation that the low-salinity stress may have a crucial role in the mass mortality. Since there was no heavy rain for the same period, the precipitation was not a possible explanation for the decrease of salinity. Physical oceanographic data taken by NFRDI (1997) clearly indicated that the SLSW was present in the area between China and Cheju Island in August 1996. This is most likely due to a freshwater supply resulting from the existence of large river runoff. Evidence of the current and the distance between the Yangtz River and Cheju Island also supports the hypothesis that source of the SLSW was the freshwater originated from the Yangtz River runoff.[macrobenthic animals, mass mortality, surface low-salinity water].

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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• pp.481-486
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• 2009

In 2007, 43.5% mortality of the cultured oyster population occurred in Gamak Bay. Mortality rapidly increase in September and peak in October. To prevent future mass-mortality event, we investigated spawning and variation of oyster body composition. The main spawning period of culture oyster occurred from August to September. Condition index and body composition (protein and glycogen) appeared to be influenced by the spawning activity. Condition index and glycogen content in September were lowest (13.5% and 5.6 mg/g, respectively). However, protein, lipid and glycogen contents did not rapidly recover after the spawning activity. The data indicates that mass-mortality of cultured oysters in Gamak Bay may be due to deteriorated health, spawning activity, stress of the high water temperature and decreasing food resources.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.723-729
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• 2012

On 3 February 2011, a mass mortality of finless porpoises Neophocaena asiaeorientalis occurred at a dike of the Saemangeum Sea dike. A total of 249 carcasses were collected; these had been stranded by a sea dike and had floated into the lake formed by the dike. Eight bodies were measured, and four of these were dissected to analyze stomach contents. The blubber thicknesses of five bodies were compared with those of caught finless porpoises in the Yellow Sea from 2010. Finless porpoises at the Saemangeum Sea dike exhibited better nutritive conditions than finless porpoises in the Yellow Sea. Air temperature in January 2011 was lower than the prior 5-year average (P<0.05). Water temperature when the mass mortality occurred was lower than values observed in 2009 and 2010: values below $0^{\circ}C$ had been recorded, and the majority of the dike lake had frozen over. The mass mortality of finless porpoises may have been caused by these unusually low temperatures.

• Hip & pelvis
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• v.36 no.2
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• pp.135-143
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• 2024

Purpose: Hip fractures are associated with increased mortality. The identification of risk factors of mortality could improve patient care. The aim of the study was to identify risk factors of mortality after surgery for a hip fracture and construct a mortality model. Materials and Methods: A cohort study was conducted on patients with hip fractures at two institutions. Five hundred and ninety-seven patients with hip fractures that were treated in the tertiary hospital, and another 147 patients that were treated in a secondary hospital. The perioperative data were collected from medical charts and interviews. Functional Assessment Measure score, Short Form-12 and mortality were recorded at 12 months. Patients and surgery variables that were associated with increased mortality were used to develop a mortality model. Results: Mortality for the whole cohort was 19.4% at one year. From the variables tested only age >80 years, American Society of Anesthesiologists category, time to surgery (>48 hours), Charlson comorbidity index, sex, use of anti-coagulants, and body mass index <25 kg/m² were associated with increased mortality and used to construct the mortality model. The area under the curve for the prediction model was 0.814. Functional outcome at one year was similar to preoperative status, even though their level of physical function dropped after the hip surgery and slowly recovered. Conclusion: The mortality prediction model that was developed in this study calculates the risk of death at one year for patients with hip fractures, is simple, and could detect high risk patients that need special management.

• The Korean Journal of Malacology
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• v.25 no.2
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• pp.93-96
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• 2009

Unexpected mass mortality has been one of the drawbacks in front of the stable production of Japanese scallop (Patinopecten yessoensis) on the Gangwon coasts of the East Sea. The preliminary data from our routine observation revealed that the mortality appeared to be related to variation of water temperature in the farming site and the degree of the mortality was dependent on scallop strain. The present study performed to verify the preliminary findings exhibited that the mortality was closely related to daily temperature variation rather than monthly variation. Daily temperature variation was particularly damageable to the scallop during the temperature elevation period. Scallops from hatchery seeds (Chinese strain) were more tolerant against the temperature variation over those from wild seeds. The hatchery scallop gain of the temperature tolerance was probably due to their larval experience to higher temperature in the hatchery as well as their maternal genetic acclimation to upper temperature extreme of the Chinese environment which was recently found.

• Journal of fish pathology
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• v.34 no.2
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• pp.255-259
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• 2021

This is the first report describing acute mass mortality occurred in juvenile olive flounder (Paralichthys olivaceus) caused by gas bubble disease (GBD). A total of 610 fish (average weight = 35 g), which were more than half of the fish acclimated at 17℃ in an aquarium, were killed within two days of acclimation. The dead and moribund fish showed excessively opened opercula and mouths, and occasionally, severe exophthalmia. Through microscopic observation, numerous gas emboli were found in the gills of the dead and live fish, while the fish were not infected with any microbial pathogens. The dissolved oxygen (DO) saturation level of the rearing water and seawater nearby the facility reached 145% and 286%, respectively, whereas other water quality parameters (such as salinity, pH, and chemical oxygen demand) were normal. The extreme saturation rate of seawater in the shore nearby seemed to be due to an enormous algal bloom that occurred there. Through molecular identification based on 18S rDNA sequences, the most dominant algal species was most closely related to Ulva californica (99.87% sequence identity) followed by U. prolifera, U. linza, and U. curvata (99.81%). Therefore, it can be concluded that supersaturated seawater due to mass algal bloom caused gas bubble disease in the olive flounder, leading to mass mortality. After technical adjustment, such as increased aeration, lowered water circulation rate, and inlet water filtration using micro-pore carbon filters, the DO level became normal, no further mortality occurred and the status of the fish was stabilized.

• Clinical Nutrition Research
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• v.13 no.2
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• pp.96-107
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• 2024

Malnutrition affect clinical outcomes in hospitalized old age patients, but the data on the related outcomes on the basis of different age categories are still limited. We aimed to investigate the interplay of associations among body mass index (BMI), falls risk, and mortality rate in different older adult patient age categories. This retrospective study included hospitalized patients aged ≥ 65 years who received artificial nutrition. Demographic, biochemical, and survival data were collected. BMI was evaluated using the World Health Organization BMI cutoffs for Asians, and patients were classified into high (≥ 23.0 kg/m²), normal (18.5-22.9 kg/m²), and low (< 18.5 kg/m²) BMI groups. The Morse Fall Scale was used to assess falls risk. By age categories, all patients (n = 4,642) were divided into the 65-74 (n = 2,649) and ≥ 75 (n = 1,993) years age groups. We found that the proportion of low-BMI and high risk of falls increased with age. Further, low-BMI was associated with increased falls risk in both age groups. Overall survival rate tended to be lower in the low-BMI and ≥ 75 years group than that in other patient groups, but did not differ significantly compared with the low-BMI and 65-74 years group. Low-BMI was associated with increased falls risk and mortality; however, the association depended on specific patient age groups.