• Analytical Science and Technology
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• v.23 no.5
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• pp.492-497
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• 2010

In this study, mercury concentrations in freshwater fish from Lake An-dong basin were investigated and were compared with the results of the national freshwater fish monitoring survey. The mercury concentrations of fish from Lake An-dong were in the range of 37~611 ng/g and Korean piscivorous chub, the top predator showed the highest average mercury concentrations, $198{\pm}97\;ng/g$. Most of fish caught from upstream of Lake An-dong were herbivorous and omnivorous, and goby minnow and pale chub showed relatively lower mercury concentrations of $21{\pm}16\;ng/g$ and $33{\pm}24\;ng/g$, respectively. Especially, mercury concentrations of long nosed barbel and largemouth bass caught from Lake An-dong were found to be higher than those of the average of the national survey monitoring data.

• Journal of Korean Society on Water Environment
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• v.29 no.2
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• pp.196-203
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• 2013

Seungchon Weir was constructed in 2010 on the downstream region of Yeongsan River watershed for four major river projects. The purpose of our study was to determine whether fish compositions and distributions differ between the upper ($U_w$) and lower regions ($L_w$) of Seungchon Weir during May - December 2011 along with hydroacoustic fish surveys using Eco-Sounder monitoring ($E_SM$) technique. Total number of fish species sampled by conventional fish sampling at all sites was 29, and 21 and 24 species occurred in the $U_w$ and $L_w$, respectively. Most dominant species was Hemiculter eigenmanni (43%) in the $U_w$ and Opsaiichthys uncirostris amurensis (21%) in the $L_w$, indicating a distinct differences of the species composition. According to hydroacoustic approach of ESM, fish density was significantly higher (p < 0.05) in the $L_w$ section of 250 m than any other sections, This outcome indicates that fishes moving toward the upstream were blocked by weir construction. According to analysis of tolerance guilds, tolerant species (TS) were made of 88% and 79% in the $U_w$ and $L_w$ region, respectively, while the proportions of sensitive species were < 0.1% of the total in the both regions. Trophic guild analysis showed that the proportion of omnivore species were 58% and 40% in the $U_w$ and $L_w$ region, respectively, while insectivores were made of 16% and 21% in the $U_w$ and $L_w$ region, respectively. Both analyses of tolerance guilds and trophic guilds indicate the biological degradation of the waterbody. Fish community structure analysis, based on species diversity, dominance, and evenness indices, showed higher community stability in the $L_w$ region than $U_w$ region. Exotic species of largemouth bass were largely increased in this survey (14%), compared to the past (< 1%), indicating a modification of fish trophic structure.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.364-371
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• 2021

Public awareness of alien species can vary by generation, period, or specific events associated with these species. An understanding of public awareness is important for the management of alien species because differences in public awareness can affect the establishment and implementation of management plans. We analyzed digital texts on social media platforms, news articles, and internet search volumes used in conservation culturomics to understand public interest and sentiment regarding alien freshwater species. The number of tweets, number of news articles, and relative search volume to 11 freshwater alien species were extracted to determine public interest. Additionally, the trend over time, seasonal variability, and repetition period of these data were confirmed. We also calculated the sentiment score and analyzed public sentiment in the collected data using sentiment analysis based on text mining techniques. The American bullfrog, nutria, bluegill, and largemouth bass drew relatively more public interest than other species. Some species showed repeated patterns in the number of Twitter posts, media coverage, and internet searches found according to the specified periods. The text mining analysis results showed negative sentiments from most people regarding alien freshwater species. Particularly, negative sentiments increased over the years after alien species were designated as ecologically disturbing species.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.207-217
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• 2021

Using the data from the national survey of fish, we determined the population size and the distribution of Micropterus salmoides, which is a translocated species into the aquatic ecosystem of Korea. . The spatial concentration of this species was determined by performing an optimized hot spot analysis. After determining potential invasiveness and risk assessment, we measured the disturbance of biodiversity in the aquatic ecosystem. The result of distribution analysis indicates that the population of M. salmoides was concentrated in the major basins of Han river, Geum river, Nakdong river, and Yeongsan-Seomjin river, including the Jeju island. In particular, Nakdong river basin showed the highest appearance rate. On the contrary, Yeongsan-Seomjin river basin showed the lowest appearance rate. The Nakdong river and the Nakdong river basin were the areas with the high spatial concentration of M. salmoides. On the other hand, only Han river basin and Geum river basin had the lowest spatial concentration. The fish invasiveness screening kit(FISK) was used to assess M. salmoides, which inhabited a broad region of aquatic ecosystem: the assessment score was 31.0, indicating its 'highly invasive' nature. Our study aims to encourage research that improves the biodiversity and the conservation of M. salmoides in a priority area.

• Journal of Life Science
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• v.22 no.1
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• pp.98-109
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• 2012

The properties of lactate dehydrogenase (EC 1.1.1.27, LDH) and expression of monocarboxylate transporters (MCTs) 1, 2, and 4 were studied in tissues from Micropterus salmoides. Native-PAGE revealed that the LDH $A_4$ isozyme was predominantly located in skeletal muscle. The LDH $A_4$, $A_2B_2$, and $B_4$ isozymes were detected in heart, liver, eye, and brain tissues, while eye-specific $C_4$ isozyme was detected in eye tissue. In September, strong LDH $B_4$ isozyme activity was detected in heart tissue. High $A_4$ isozyme activity was noted in all other tissues except heart tissue. However, in November, strong $A_4$ isozyme activity was detected in heart tissue. The LDH/CS (Citrate synthase, EC 4.1.3.7) ratio in skeletal muscle and heart tissues indicated that anaerobic metabolism was high in those tissues. Native-PAGE after immunoprecipitation showed that eye-specific $C_4$ isozyme was more similar to the $A_4$ than the $B_4$ isozyme. The LDH $A_4$ isozyme was purified by affinity chromatography. The molecular weight of subunit A was 37,200. The LDH activity in tissues was consistently 11.05~28.32% due to inhibition by 10 mM pyruvate. The $K_m^{PYR}$ of LDH in eye tissue was very low. The optimum pH for LDH in tissues was pH 7.5~8.0. The LDH $A_4$ isozyme was detected in mitochondria of skeletal muscle, whereas the $B_4$ and $A_2B_2$ isozymes were detected in heart tissue mitochondria. Western blot analysis indicated that MCTs 1, 2, and 4 were located in the plasma membrane and mitochondria of skeletal muscle and heart tissues. The sizes of MCTs 1, 2, and 4 in skeletal muscle were 60, 54~38, and 63 kDa, while those in heart tissue were 57, 54~38, and 55.5 kDa, respectively. In conclusion, M. salmoides appears to use anaerobic metabolism predominantly when adapted to a hypoxic environment. In highly activated skeletal muscle and heart tissue, energy production is controlled by inward and outward flows of pyruvate and lactate through MCTs 1, 2, and 4 in the plasma membrane and mitochondria, with effective adjustment by LDH isozymes.