• Korean Journal of Environment and Ecology
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• v.34 no.2
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• pp.142-156
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• 2020

This study surveyed Gyeongan Stream, a tributary of the Han River Drainage System, from April to October 2017 to investigate the characteristics of fish communities. The survey collected 40 species of 11 families from 48 survey stations using kick nets and cast nets. The dominant and subdominant species were Zacco platypus (48.0%) and Rhynchocypris oxycephalus (17.7%), respectively. The next most abundant species were Pungtungia herzi (6.8%), Z. koreanus (5.0%), Carassius auratus (4.3%), Squalidus gracilis majimae (2.7%), and Rhodeus notatus (2.5%). Among the fish collected, 14 species (35.0%) were Korean endemic species, and the exotic species were Micropterus salmoides, Lepomis macrochirus, and Cyprinus carpio (Israeli type). The land-locked species were Plecoglossus altivelis, Rhinogobius brunneus, and Cottus koreanus, while the species sensitive to climate change was C. koreanus. The community analysis showed that the dominance was higher at the uppermost stream station, whereas diversity and abundance tended to be lower at the upstream station and higher toward the downstream station. The community structure was largely divided into rivers (uppermost stream, upstream, and middle-lower stream) and lake. The river health was mostly good (23 stations, 47.9%) and fair (15 stations, 31.3%). Comparison with past surveys showed that 12 species identified in the past surveys did not appear in this survey; nine species appeared for the first time in this survey; and the ecosystem disturbance species - M. salmoides and L. macrochirus - tended to spread more widely gradually.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.582-588
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• 2013

The impact of global warming on aquatic systems has been a priority research area in the past decade. However, the possibility that increased temperatures will cause shifts in viral disease outbreaks has not been well addressed. In the present study, with increasing water temperature (WT) in the coastal area of Korea, we estimated the possibility of changes in fish viral diseases. From the present time, WT may rise between 0.62 and $1.7^{\circ}C$ by 2050, and the effect on aquaculture could be more adverse than benefitial. Red seabream iridovirus disease (RSIVD) and viral nervous necrosis (VNN) cause high mortality above 22 and $24^{\circ}C$, respectively, and outbreaks could commence earlier and persist for prolonged periods. Nevertheless, the period of occurrence of viral hemorrhagic septicemia (VHS), which outbreaks at a lower WT (< $18^{\circ}C$), could be shorter than the current infectious period. Thermal stress in fish causes reductions in growth and immunocompetence; thus, increases in summer WT can lead to the development of new viral diseases. WT has a strong influence on fish population dynamics; therefore, entry of new viruses and changes in the prevalence of infection can be expected if carrier fishes are introduced or migrate to Korean waters.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.12-18
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• 1998

Tremendous progress has been made over the past quarter-century studying the genetics of gametogenesis and the resulting gametes and embryos. Studies merging molecular techniques and conventional cytogenetics are now beginning to bridge the gap between what we have learned about the meiotic process in males and females and what we know of the mitotic chromosomes of zygotes. Numerical abnormalities in sperm, oocytes and embryo can now diagnosed by fluorescence in situ hybridization (FISH). "At risk" couples can, therefore, have only unaffected embryos replaced in the sterus and avoid the possibility of terminating a pregnancy that might only be diagnosed as affected later gestation. Single-cell genetic analysis has also provided powerful tools for studying genetic defects arising during early human development. Recent studies of sperms, oocytes and cleavage-stage human embryos have revealed an unexpectedly high incidence. These genetic abnormalities are likely to contribute to early pregnancy loss and have important implications for improving pregnancy rates in infertile couples by assisted reproduction. The widespread use of preimplantation genetic diagnosis (PGD) awaits further documentatio of safety and accuracy. Other issues also must be addressed. First, the ethical issues regarding germ cell and embryo screening must be addressed including what diseases are serious enough to warrant the procedure. Another concern is the use of this technology for non-genetic disorders such as gender selection. Finally, the experimental nature of these procedure must continually be discussed with patients, and long-term follow-up studies must be undertaken. Development of more accurate and less expensive assays coupled with improved assisted reproductive technology success rates may make PGD a more widely use clinical tool. The future awaits these development.velopment.

• Parasites, Hosts and Diseases
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• v.52 no.4
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• pp.391-397
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• 2014

We evaluated the status of Clonorchis sinensis infection and potential risk factors among residents of riverside areas (Geumgang) in Muju-gun, Jeollabuk-do (Province), Korea. From January to February 2010, a total of 349 (171 males, 178 females) stool samples were collected and examined by the formalin-ether concentration technique. Also, village residents were interviewed using questionnaires to obtain information about C. sinensis infection-related risk factors. Overall egg-positive rate of C. sinensis was 13.2%. Egg-positive rates were significantly higher in males, farmers, and residents who had lived there more than 20 years, and in residents who had eaten raw freshwater fish than in opposite groups, respectively. However, there was no significant difference between age groups, education levels, cigarette smoking, alcohol drinking, health status, past history of infection, and experience of clonorchiasis medication and examination. Logistic regression analysis was performed to determine risk factors for clonorchiasis. On univariate analysis, the odds ratios for males, farmers, those who had lived there more than 20 years, and who had eaten raw freshwater fish were 2.41, 4.44, 3.16, and 4.88 times higher than those of the opposites, respectively. On multivariate analysis, the odds ratio of residents who had eaten raw freshwater fish was 3.2-fold higher than that of those who had not. These results indicate that residents living in Muju-gun, along the Geum River, Korea, have relatively high C. sinensis egg-positive rates, and the habit of eating raw freshwater fish was the major factor for the maintenance of clonorchiasis.

• Journal of Marine Bioscience and Biotechnology
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• v.3 no.1
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• pp.54-60
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• 2008

Compared to other North African countries, Tunisia has reached a significant level of fish consumption. The only relevant historical dimension of aquaculture in Tunisia are traditional lagoon management (80,000 ha of lagoon and coastal lakes) and culture of shellfish. Semi-intensive and intensive cultures are relatively new concepts in Tunisia and only recently also the public sector is involved. The Tunisian fishing industry has expanded over the last 20 years and annual catches at present are more than four times those registered in mid-fifties. Production of the year 2007 reached 105 thousand tons against 111 thousand tons during the same period of 2006 thus recording a fall of 5%. Unfavorable weather conditions mainly during the last quarter year had the effect to reduce the number of days out at sea. Exports reached 24.3 thousand tons for one value 240.5 MD against respectively 22.2 thousand tons and 234.1 thus recording MD at the end of the past year a rise of 9% in volume and from 3% in value. Commercial value such as shellfish - consequence of one regression of the production - with in parallel raises blue fish exports. The imports were stabilized in volume of 39.1 thousand tons and increased from 6% in value with respectively 67.4 MD in 2007 against 63.7 MD at the end of 2006. The importation in larger quantities of intended fish to the fattening of tuna in floating cages explains partly this rise. Nevertheless, the pay of balance import/export of produced fishing remains positive with a surplus of 173.1 MD against 170.4 MD in 2006.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.194-201
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• 2022

Purpose: This study investigated the relationship between climate factors and the catches in Korean offshore fisheries in recent three decades (1981 to 2010). Method: This study focused on seven types of fish species preferred in Korean cuisine. In the study, 10-year moving averages were used so that long-term trends could be easily identified. Results: Both air temperature and sea surface temperature (SST) on the coast of Korea rose in the period (p < 0.05). The rise in SST was significantly correlated with the rise in air temperature (p < 0.05), but not with precipitation. In the 2010s compared to in the 1981, catches of anchovy and squid greatly increased (p < 0.05), while catches of Alaska / walleye pollock has been almost extinct over the past 30 years. As such, cold-water fish species decreased or disappeared, and their fishing ground was replaced by warm-water fish species. Conclusions: These findings indicate that fish species caught in offshore fisheries of Korea have changed due to climate change, especially warming. This suggests that the warming of the Korean Peninsula may have a significant impact on the supply of fishery products and food security to Koreans in the near future.

• Korean Journal of Ichthyology
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• v.24 no.2
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• pp.84-93
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• 2012

Fish species composition and abundance in the waters of nearby Nakdong River estuary were investigated non-continuously and seasonally by shrimp beam trawl in summer 2007, winter 2009, and from spring 2010 to autumn 2010. During the study period, total fish species were collected 92 species, 36 families in study area. Shannon index was 1.893~2.962, and evenness was 0.050~0.231. Fish species composition was shown interannually and seasonally variations in the waters of nearby Nakdong River estuary. We carryed out cluster analysis to contain the data in previous and current study. Fish species composition was divided 3 groups which were 1987~1988 and 1998, 2001~2002, and 2007~2008 and 2009~2010. Average and minimum length in this study was longer than its in previous studies, and length range in this study was wider than its in previous studies, too. Dominant fish increased individuals and weight per unit area in this study. Especially Lophius litulon, Raja kenojei, Eopsetta grigorjewi, and Zeus faber were much better than past 2002. Liparis tanakai, Repomucenus valenciennei and Leiognathus nuchalis were dominant fish in previous study, but those decreased individuals and weight per unit area in this study.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.71-80
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• 2022

In the past, fish diseases were bacterial in aqua farms, but in recent years, the frequency of fish diseases has increased as they have become viral and mixed. Viral diseases in an enclosed space called a aqua farm have a high spread rate, so it is very likely to lead to mass death. Fast identification of fish diseases is important to prevent group death. However, diagnosis of fish diseases requires a high level of expertise and it is difficult to visually check the condition of fish every time. In order to prevent the spread of the disease, an automatic identification system of diseases or fish is needed. In this paper, in order to improve the performance of the disease identification system of Paralichthys olivaceus based on deep learning, the existing pre-processing method is compared and tested. Target diseases were selected from three most frequent diseases such as Scutica, Vibrio, and Lymphocystis in Paralichthys olivaceus. The RGB, HLS, HSV, LAB, LUV, XYZ, and YCRCV were used as image pre-processing methods. As a result of the experiment, HLS was able to get the best results than using general RGB. It is expected that the fish disease identification system can be advanced by improving the recognition rate of diseases in a simple way.

• Korean Journal of Heritage: History & Science
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• v.55 no.3
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• pp.132-150
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• 2022

Designated as a national intangible cultural asset, the fish weir is a traditional fishing method and was a leading fishing tool in Korean coastal fishery. As the littoral sea area fishing vessel fishery developed since the 1970s, traditional fishing methods including fish weirs began to decline. The fish weir has been passed down in the form of tools such as fish weirs, stone weirs, and bamboo weirs. In Namhae-gun and Sacheon City in Gyeongsangnam-do, anchovies are caught using bamboo weirs. A basic bamboo weir consists of a fish trap(balgong), a space where fish gather together, and a V- or U-shaped wooden fence(halgaji) that helps fish come inside the fish trap. Its fishing method is to catch fish that have come to the coast during high tide alongside those are stuck inside fish traps(balgong) with nets or scoop nets. This paper examined the process of passing down traditional fishing methods through a comparative analysis of the bamboo weir structures and fishing methods in the Namhae and Sacheon regions. First, the historical process of assembling the current bamboo weir structure was analyzed. The bamboo weir, a fishing tool, appears to have combined the features of past weirs and fish weirs based on the Jijok Strait and Samcheonpo Strait. Next, this paper examined the structure and fishing method of the two types of bamboo weirs made with a circular or square fish trap(balgong) where fish gather. Through this analysis, this study examined the lives of fishermen who have adapted to their natural environment and actively utilized obtainable resources(materials), and then changed the traditional fishing method of bamboo weirs and developed them into an appropriate technology. Lastly, a new value attributed to anchovies caught using bamboo weirs was analyzed. This new value extracted from better bamboo weir anchovies works as a mechanism to uphold the tradition of anchovy-catching bamboo-weir fishing, which produces a smaller amount of anchovies compared to other methods of anchovy fishing. In this way, bamboo weir fishing has been passed down as a result of its differentiated aspect of producing better anchovies than those produced with other fishing methods, as well as the historical aspect of it being a traditional fishing method.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.603-614
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• 2022

This study investigated the characteristics of fish communities in the Bangtaecheon Stream in Korea from April to October 2020. The survey collected 4,640 fish of 26 species in 9 families from 11 survey stations. The dominant and subdominant species were Rhynchocypris kumgangensis(relative abundance at 31.5%) and Zacco koreanus(27.8%), respectively. The next most abundant species were Ladislavia taczanowskii(15.9%), Pungtungia herzi(4.0%), Brachymystax lenok tsinlingensis(3.7%), Microphysogobio longidorsalis(2.4%), and Zacco platypus(2.3%). Among the collected fish species, 17 (65.4%) were Korean endemic species, 4 (15.4%), including Acheilognathus signifer, Pseudopungtungia tenuicorpa, Gobiobotia brevibarba, and B. l. tsinlingensis,were class II endangered wildlife as designated by the Ministry of Environment, and 1 species, Hemibarbus mylodon, was a natural monument. Moreover, two landlocked species (B. l. tsinlingensisand C. koreanus) were also collected. Additionally, four cold-water species (R. kumgangensis, L. taczanowskii, B. l. tsinlingensis,and Cottus koreanus) were collected, and all of them mainly inhabited the upper and middle streams. Fish community analysis showed a tendency for dominance and uniformity to decrease and abundance and diversity to increase from upstream to downstream and that the community structure was divided into upstream and downstream groups. The river health was rated as excellent (9 stations) and good (2 stations). Compared to the previous studies, three species (Carassius auratus, Leiocassis ussuriensis,and Siniperca scherzeri) appeared in the past but did not appear in this survey, and three species (Opsariichthys uncirostris amurensis, Microphysogobio yaluensis,and Orthrias nudus) that did not appear in the past appeared in this survey. Bangtaecheon Steam is well-preserved, and climate-sensitive species, endangered wildlife, and natural monuments inhabit the stream. Therefore, continuous attention and systematic conservation measures are required.