• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.50 no.4
• /
• pp.429-436
• /
• 2017

The seasonal and interannual variations in fish assemblages in the coastal waters off Gijang were examined with an otter trawl from 2015 to 2016. A total of 59 fish species was collected during the study period. The dominant species were Caelorinchus multispinulosus, Clupea pallasii pallasii and Chelidonichthys spinosus. Seasonal changes in fish assemblages appeared to be distinct in the study area. The fish assemblages in summer and autumn were clearly distinguishable from those in other seasons, and the largest numbers of species and individuals were captured in winter and summer, respectively. Because fish assemblages are closely related to changes in water temperature, long-term changes in water temperature can have a significant impact on the productivity of offshore fisheries by changing fish species composition, habitat migration, and growth rate of fish.

• Korean Journal of Environmental Biology
• /
• v.23 no.3 s.59
• /
• pp.315-321
• /
• 2005

The population of river otter (Lutra lutra) has been declined most of the world due to hunting, habitat destruction and indirect or direct influences of eutrophication, acidification and toxic chemicals. This study is conducted to identify the population decline of river otter in Korea with relation to environmental pollution caused by accumulation of heavy and flared metals. The field survey was conducted during Jan~Dec, 2004 at a monthly basis by collecting spraints. A total of 228 spraints were collected and analysis was done by ICP-AES. The concentrations of fourteen metals (Cr, Zn, Cd, Pb, Ni, Fe, Co, Mn, Mg, Cu, Al, Ba Hg, As) have been determined. Annual concentrations of Cd $(1.38{\mu}g\;g^{-1}),\;Zn\;(599.06\;{\mu}g\;g^{-1}),\;Pb\;(5.54\;{\mu}g\;g^{-1})$ at Gucheon were higher than those of Yeonchocheon. Concentrations of $Cr\;(5.01{\mu}g\;g^{-1}),\;Ni\;(1.91{\mu}g\;g^{-1}),\;Co\;(0.25{\mu}g\;g^{-1})$ were higher at Yeonchocheon. Most metals in winter were significantly increased (P<0.05) as season progressed from spring to winter. $Pb\;(15.58{\mu}g\;g^{-1}),\;Cu\;(15.15{\mu}g\;g^{-1}),\;a;Guchoen\;and\;Cr\;(5.77{\mu}g\;g^{-1})$ at Yeonchocheon were high in the downstream of winter.

• Korean Journal of Environment and Ecology
• /
• v.35 no.1
• /
• pp.24-36
• /
• 2021

Countries around the world, including the Republic of Korea, are participating in efforts to preserve biodiversity. Concerning species, in particular, studies that aim to find potential habitats and establish conservation plans by conducting habitat suitability analysis for specific species are actively ongoing. However, few studies on mid- to long-term changes in suitable habitat areas are based on accumulated information. Therefore, this study aimed to analyze the time-series changes in the habitat suitable area and examine the otters' changing pattern (Lutra lutra) designated as Level 1 endangered wildlife in Gangwon-do. The time-series change analysis used the data on otter species' presence points from the 2nd, 3rd, and 4th national natural environment surveys conducted for about 20 years. Moreover, it utilized the land cover map consistent with the survey period to create environmental variables to reflect each survey period's habitat environment. The suitable habitat area analysis used the MaxEnt model that can run based only on the species presence information, and it has been proven to be reliable by previous studies. The study derived the habitat suitability map for otters in each survey period, and it showed a tendency that habitats were distributed around rivers. Comparing the response curves of the environmental variables derived from the modeling identified the characteristics of the habitat favored by otters. The examination of habitats' change by survey period showed that the habitats based on the 2nd National Natural Environment Survey had the widest distribution. The habitats of the 3rd and 4th surveys showed a tendency of decrease in area. Moreover, the study aggregated the analysis results of the three survey periods and analyzed and categorized the habitat's changing pattern. The type of change proposed different conservation plans, such as field surveys, monitoring, protected area establishment, and restoration plan. This study is significant because it produced a comprehensive analysis map that showed the time-series changes of the location and area of the otter habitat and proposed a conservation plan that is necessary according to the type of habitat change by region. We believe that the method proposed in this study and its results can be used as reference data for establishing a habitat conservation and management plan in the future.

• Korean Journal of Heritage: History & Science
• /
• v.43 no.1
• /
• pp.118-127
• /
• 2010

From January to December of 2006, the distribution characteristics and density of otter(Lutra lutra ) feces were studied at Seosi stream, a tributary of Seomjin river, in Gurye-gun, Jeollanam-do. During the study period, the number of excretion site, old feces, and new feces were observed six times in seven habitat sections of the stream. As the result, 222 excretion sites, 662 old feces (converts to 718 per 60 days), and 364 new feces were observed. All of these were observed the most in January. Mean density per 500m was 26.9 for excretion sites, 88.6 for old feces, and 44.4 for new feces. Monthly changes in the number of excretion site and feces per section showed that otters have no specific preference to a habitat section of Seosi stream over the year.

• Korean Journal of Ecology and Environment
• /
• v.53 no.1
• /
• pp.80-90
• /
• 2020

In order to understand the stress responses, we measured the concentration of stress hormones by using the fresh feces of wild otters in the Gwangju stream and Seomjin river during summer and winter in 2018. We compared seasonal and regional number of spraints (=otters' feces), temperature, altitude, water width, land cover, and water quality with stress hormones. The stress hormone levels were higher in summer than in winter, and significantly different to season and region. In addition, the number of feces were different according to the season and region, and showed a negative correlation with stress hormone. This study suggested assessing stress hormones as another promising method for the analysis of status of wild otters and it will contribute to establish the management and conservation policy, especially in urban area.

• Korean Journal of Environmental Biology
• /
• v.24 no.2 s.62
• /
• pp.160-165
• /
• 2006

The purpose of this study was to ascertain the prey composition and utilization of the Eurasian otter, Lutra lutra, in the ecosystem conservation region of the Seomjin River. The study was conducted for a 12-month period from March 2003 to February 2004 by spraints analysis and an investigation using artificial holts. We found seasonal variation in the number of spraints and composition of prey items. Fish were the main prey items throughout the period (82%), and other prey items included birds (14%), amphibians (2%) and arthropods (1%). In addition to prey identification, we investigated habitat utilization by otters through spraints distribution. The traces of otters were discovered in five of the six total artificial holts. However, the utilization of the artificial holts in the study area seemed to be limited as evidenced by the low frequency of traces in the holts.

• Journal of Environmental Science International
• /
• v.26 no.4
• /
• pp.457-466
• /
• 2017

The extensive construction works of container terminals progressed since 2006 was converted to small scaled construction works or reclaiming works since 2012 in Busan New Port area. To investigate changes in activity of otters with the change of construction work scales, the linear densities of spraints at 15 localities of 5 areas (I-V) near the Busan New Port construction areas were surveyed during the period from 2012 to 2016. As the results, the average linear density of spraints has a tendency to increase since 2014. That is, the linear densities of spraints have increased at the area II and IV where the reclaiming works have been progressed, although have decreased or unchanged in the areas I, III and V where small scaled construction works have been progressed. Based on the fact that there were habitats at the Honamdo in the area II and the Yeondo in the area IV, otters seemed to restore their activities around the habitats as the center regardless of the reclaiming works.

• Journal of Korean Society for Geospatial Information Science
• /
• v.20 no.3
• /
• pp.11-18
• /
• 2012

Increasing concern about biodiversity has lead to a rise in demand on the spatial assessment of biological resources such as biodiversity assessment, protected area selection, habitat management and restoration in Korea. The purpose of this study is to create species richness map through data collection and modeling techniques for wildlife habitat assessment. The GAM (Generalized Additive Model) is easy to interpret and shows better relationship between environmental variables and a response variable than an existing overlap analysis and GLM (Generalized Linear Model). The study area delineated by a large watershed contains Jirisan national park, Mt. Baekun and Sumjin river with three kinds of protected areas (a national park, a landscape ecology protected area and an otter protected area). We collected the presence-absence data for wildlife (mammals and birds) using a stratified random sampling based on a land cover in the study area and implemented natural and socio-environmental data affecting wildlife habitats. After doing a habitat use analysis and specifying significant factors for each species, we built habitat suitability models using a presence-absence model and created habitat suitability maps for each species. Biodiversity maps were generated by taxa and all species using habitat suitability maps. Significant factors affecting each species habitat were different according to their habitat selection. Although some species like a water deer or a great tit were distributed at the low elevation, most potential habitats for mammals and birds were found at the edge of a national park boundary or near a forest around the medium elevation of a mountain range. This study will be used for a basis on biodiversity assessment and proected area selection carried out by Ministry of Environment.

• Journal of Environmental Impact Assessment
• /
• v.30 no.1
• /
• pp.13-23
• /
• 2021

In this study, we performed a Random Walker analysis to predict the Major Movement Paths of otters. The scope of the research was a simulation analysis with a radius of 7.5 km set as the final range centered on the Ansim-wetland in Daegu City, and a field survey was used to verify the model. The number of virtual otters was set to 1,000, the number of moving steps was set to 1,000 steps per grid, and simulations were performed on a total of 841 grids. As a result of the analysis, an average of 147.6 objects arrived at the boundary point under the condition of an interval of 50 m. As a result of the simulation verification, 8 points (13.1%) were found in the area where the movement probability was very high, and 9 points (14.8%) were found in the area where the movement probability was high. On the other hand, in areas with low movement paths probabilities, there were 8 points (13.1%) in low areas and 4 points (6.6%) in very low areas. Simulation verification results In areas with high otter values, the actual otter format probability was particularly high. In addition, as a result of investigating the correlation with the otter appearance point according to the unit area of the evaluation star of the movement probability, it seems that 6.8 traces were found per unit area in the area where the movement probability is the highest. In areas where the probability of movement is low, analysis was performed at 0.1 points. On the side where otters use the major movement paths of the river area, the normal level was exceeded, and as a result, in the area, 23 (63.9%), many form traces were found, along the major movement paths of the simulation. It turned out that the actual otter inhabits. The EN-Simulator analysis can predict how spatial properties affect the likelihood of major movement paths selection, and the analytical values are used to utilize additional habitats within the major movement paths. It is judged that it can be used as basic data such as to grasp the danger area of road kill in advance and prevent it.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.16 no.4
• /
• pp.99-114
• /
• 2013

In this study, constructability of ecologocal stream restoration process was evaluated and improved approaches for habitat were suggested. The study site is Gucheon River in Geoje city where conducted ecologocal restoration work within maintaining its flood control function. Application of ecological design factors and constructability in the process from planning to construction was analyzed and its results are as follows: In the process of planning and designing, it was focused more on the naturality of Gucheon River rather than the human convinience and ecological design factors were applied within the ecological capacity of the site. First, the indexes for constructability evaluation is selected. It was classified into three major categories as construction quality, design quality and construction administration system. Each index has details, so there are twenty sub indexes for contractibility evaluation. Second, the evaluation results shows that the index most in need of improvement was plumbing construction, followed by Stone construction and pavement construction. design concept was evaluated as appropriate in entire categories. Finally it is suggested that it can be improved in both process of design to enhance the technology and process of construction to enhance the quality management. The constructability of ecological stream needs adaptive management and it must be discussed with its designing which is at the stage before construction. Also it needs discussion with its designer constantly and feed-back process.