Monthly fluctuation in abundance and species composition of fish in coastal waters off Oenaro island, Goheung were investigated using seasonal samples collected by a shrimp beam trawl in 2018. A total of 5,981 fishes were sampled and classified into 48 species, 32 families, and 9 orders. The dominant species was Engraulis japonicus (993 individuals, 16.60%), Amblychaeturichthys hexanema (844 individuals, 14.11%), and Thryssa kammalensis (674 individuals, 11.27%). The highest number of individuals was found in August (958 individuals), while the lowest number of individuals was found in January (136 individuals). The diversity index was the highest in November (H’ = 2.37) and the lowest in January (H’ = 1.77).
The species composition and variation in abundance of fishery resources near Oenarodo, Go-heung Peninsula, Korea, were investigated by gill net, trap net, and longline in May, July, and October 2015 and 2016. During the study period, the total catch included 14 species in the gill net, 11 species in the trap net, and 4 species in the longline. The dominant species were Portunus trituberculatus and Raja pulchrain the gill net, Charybdis japonicaand and Octopus vulgarisin in the trap net, and Muraenesox cinereusin in the longline. The Catch Per Unit Effort (CPUE) per individual and per weight in the gill net were similar in May and July of 2015 and 2016. In October 2015, the CPUE per individual was 2.1 ind./h and the CPUE per weight was 505 g/h higher than the results in 2016, but there was no significant difference in the total CPUE between 2015 and 2016. In the trap net, the CPUE per weight was similar in both 2015 and 2016, but the CPUE per individual was 2.7 ind./h higher in October 2015 than in October 2016 and the total CPUE was not significantly different from 2015 to 2016. The CPUE per individual and weight in the longline were significantly higher in July and October 2015 than in the same months of 2016, but the total CPUE in 2015 and 2016 did not show a significant difference.
The fluctuation in the abundance and species composition of fish was investigated using gape net in Dolsan District of Yeosu Korea from July 2015 to April 2016. A total of 1,331 fishes were sampled and classified into 30 orders, 42 families, and 53 species. The dominant orders are Perciformes including 21 famailies and 24 species, followed by Scorpaeniformes including 7 families and 13 species, and Clueiformes including 6 families and 6 species. Among the 53 fish species collected, Engraulis japonicus was the most frequent species occupying 43.5%, followed by Argyrosomus argentatus (23.8%), and Leiognathus nuchalis (22.4%). The monthly diversity, evenness, and richness index were 1.83-2.90, 0.76-0.95 and 3.06-6.40.
Mosquitoes and hard ticks are vectors of serious diseases, but factors affecting the abundance and distribution of vector species are not well-understood. Therefore, we monitored mosquito populations from three potential mosquito habitats using black light traps and BG-Sentinel traps in Gyeonggi-do, 2016. Also, we surveyed ticks using CO2-based traps at one location in Gyeonggi-do, 2016. From the traps, we collected a total of 4,818 mosquitoes in three potential mosquito habitats, and 3,207 ticks in Gyeonggi-do. Among the collected samples, the highest density of mosquitoes were observed in August, and tick density was highest in August either. In the samples, dominant mosquitoes were Aedes vexans nipponii (Species Ratio 49%), and Culex pipens pallens (SR 25%) in mosquito habitats and dominant ticks were Haemaphysalis longicornis (SR 56%) in Gyeonggi-do. This monitoring program for vector species can help develop effective management strategy, especially under the global climate change.
Seasonal abundance and distribution of mosquitoes and chigger mites are important for human populations. However, factors affecting the abundance and distribution of vector species are not well - understood. Furthermore, global climate change makes it difficult to predict the population dynamics of vector species. Therefore, it is important to monitor this vector species over a long period of time. In 2015, mosquitoes were collected from three potential mosquito habitats using black light trap and BG-Sentinel trap in Gyeongi-do in April through October. Also, we collected chigger mite using sherman live traps in Cheorwon, Gangwon-do in April, September and October. From the survey, we collected a total of 11,649 mosquitoes in three potential mosquito habitats, and a total of 3,656 chigger mites from 54 wild rodents. In the samples, dominant mosquito species were Aedes vexans nipponii (Species Ratio 70%), Culex pipens pallens (SR 9.8%) in Gyeonggi area and dominant chigger mite species was Leptotrombidium pallidium (SR 59%) in Cheorwon. The results of this study can serve as provide fundamental basis to develop effective management strategy under the global climate change environment.
The purpose of this study is to compare the ichthyofauna between the eelgrass bed waters located in the open sea and the nearby sea free of eelgrass, and this study collected a total of 26 species. Comparing the fish collected on the eelgrass bed (St.2) of Geomun–do coast with the fish collected on the coastal waters (St.1) void of the nearby eelgrass bed, the fish collected from the eelgrass bed included 19 species, 413 individual with 16,110.6g in weight while the fish collected from the coastal waters void of the eelgrass bed included 19 species, 290 individuals with 12,961.5g in weight. Accordingly, it was found that the population size and biomass of the fish collected from the eelgrass bed were higher than the coastal waters void of the eelgrass. This study could identify that diversity, richness, evenness index except dominance were also much higher even in the result of cluster analysis.
Mosquitoes are vectors of many human diseases such as Japanese encephalitis, vivax malaria, west nile fever, dengue fever and yellow fever. However, factors affecting the abundance and distribution of mosquitoes are not well-understood. Moreover, the global climate change makes it even more difficult to address and predict the population dynamics of mosquitoes. Therefore, it is important to monitor this medically-important pest throughout landscapes over a long period of time. This study was conducted as a part of the nation-wide surveillance program to monitor insect vectors. In 2015, mosquitoes were collected using black light traps and BG-Sentinel traps in Gyeonggi-do at every two weeks from April to September. Three types of potential mosquito habitats were selected for surveillance: urban area (Suwon), cattle shed (Yongin) and wild bird refuge (Gwangju). Among the three habitats, female mosquitoes were first caught on April 4 by BG-Sentinel trap in the urban area. The highest density of female mosquitoes in the traps was recorded in July in the urban area (134 ± 84 per trap); the highest density was observed in June in the cattle shed (2473 ± 1319) and wild bird refuge (21 ± 15) (mean ± SE). The dominant mosquito species were Culex pipens pallens (91%), Aedes vexans nipponii (79%) and Anopheles sinensis (33%) in the urban area, cattle shed and wild bird refuge, respectively. The results of this study indicate that female mosquitoes were most abundant in the cattle shed habitat type. It is also noteworthy that the dominant mosquito species varied among the habitat types surveyed. This nation-wide monitoring program for medical pests will provide fundamental basis to develop effective management strategy under the global climate change environment.
Monthly variation in abundance and species composition of the fishes were investigated based on specimens collected by gill net in coastal water of Yeosu from October, 2009 and February, May, August, 2010. The collected fishes were 1,529 individuals (183,840g) of the total, identified into 6 orders, 16 families and 24 species. The most dominant order fish was Perciformes comprised 9 species, 7 families, and followed Pleuronectiformes comprised 5 species, 3 families, Scorpaeniformes comprised 5 species, 2 families. These 3 orders constituted 81.1% of the total collected fish. During the study, most dominant species was Hexagrammos otakii accounted for 189 individuals (12.4%) of the total, followed by Lateolabrax japonicus 165 individuals (10.8%), Hexagrammos agrammus 154 individuals (10.0%). The fish was collected by a gill net in coastal water of Yeosu from October, 2009 and February, May, August, 2010, the diversity index of the fishes was 2.09~2.66, which was the highest in August, 2010 and the lowest in February, 2010. The evenness index of them was 0.84~0.89, which was the highest in August, 2010 and the lowest in February, 2010 and the richness index of them was 2.02~3.14, which was the highest in October, 2009 and the lowest in February, 2010. The analyzed species diversity index by the each stations was 2.47~2.66 and the evenness index was 0.84~0.90 and the richness index 2.99~3.37. The similarity of community structure per season was very high which was the least in spring and fall. In addition, the community structure was very similar in state 3 and 2 out of each stations.
The objectives of this study to determine seasonal changes in species composition and abundance of fish and decapod assemblage, and the relationships between environmental factors and their abundance in an eelgrass bed of Jindong Bay. A total of 26 fish species and 29 decapod species were collected by a small beam trawl from an eelgrass bed in Jindong Bay in 2002. The dominant fish species were Hexagrammos otakii, Pholis neulosa and P. fangi and these accounted for 48.4 % in the total number of individuals. Dominant decapod taxa were Palaemon macrodactylus, Charybdis japonica, Pagurus minutus and C. bimaculata. These were primarily small species or early juveniles of larger species. Species composition and abundance varied greatly showing a peak in the number of individuals in April and May, and peak biomass in fish in July and decapods in August. Catch rate was low in winter months both in fish and in decapod. Seasonal changes in the abundance of fishes and decapods corresponded with eelgrass biomass and abundance of food organisms indirectly.
지구온난화로 인해 고산지역에 고립되어 서식하는 고산종은 감소할 가능성이 높다. 본 연구는 한라산 고지대에 서식하는 10종의 유존 나비종의 서식실태를 파악하기 위해 수행되었다. 고지대의 나비조사는 한라산 정상부의 초지에서 2007년부터 6년간 실시하였다. 유존종의 나비가 저지대에 나타나는 지 확인하기 위해 2012년에는 저지대의 2곳에서 조사를 하였다. 나비는 선조사법으로 조사하였다. 10종의 유존 나비종들은 고지대에서는 관찰이 되었으나, 저지대에서는 관찰되지 않았다. 이들 종들은 대부분 개체수가 많고 개체군의 안정성이 다른 나비들에 비해 낮지 않았다. 밀도 변화를 분석한 결과 유존종의 나비들이 감소하거나 증가하는 경향은 나타나지 않았다. 따라서 기후변화의 영향은 아직은 유존 나비종의 개체군에 명확하게 나타나지는 않았다. 본 조사결과와 우리나라의 출현자료를 토대로 각 유존종에 대한 취약성 평가를 하였다.
An Individual-Based Model (IBM) was developed by employing natural and toxic survival rates of individuals to elucidate the community responses of benthic macroinvertebrates to anthropogenic disturbance in the streams. Experimental models (doseresponse and relative sensitivity) and mathematical models (power law and negative exponential distribution) were applied to determinate the individual survival rates due to acute toxicity in stressful conditions. A power law was additionally used to present the natural survival rate. Life events, covering movement, exposure to contaminants, death and reproduction, were simulated in the IBM at the individual level in small (1 m) and short (1 week) scales to produce species abundance distributions (SADs) at the community level in large (5 km) and long (1~2 years) scales. Consequently, the SADs, such as geometric series, log-series, and log-normal distribution, were accordingly observed at severely (Biological Monitoring Working Party (BMWP⁄10), intermediately (BMWP⁄40) and weakly (BMWP›50) polluted sites. The results from a power law and negative exponential distribution were suitably fitted to the field data across the different levels of pollution, according to the Kolmogorov-Smirnov test. The IBMs incorporating natural and toxic survival rates in individuals were useful for presenting community responses to disturbances and could be utilized as an integrative tool to elucidate community establishment processes in benthic macroinvertebrates in the streams.
Species composition and abundance of larval fishes in the coastal waters off Gori in the southeastern Korea were investigated from January to December in 2006. During the study period, 32 larvae species belonging to 20 families were collected. The dominant species were Engraulis japonicius, Hexagrammos agrammus, Sillago japonicus, Acropoma japonicum, Apogon lineatus, and Konosirus punctatus. These six species accounted for 87.0% of the total number of individuals collected. The number of species, number of individuals, and species diversity indices fluctuated by season. The peak numbers of species and individuals occurred in July and May, respectively. Correlation analysis showed that monthly variations in water temperature and salinity could act as an indicators of seasonal variations in the larval fish community structure and abundance of the dominant species; in particular, the abundance of S. japonicus, A. japonicum, and A. lineatus were significantly corrected with the water temperature.
Changes in insect communities are one of the best indicators of environmental changes. A survey was conducted using the Flight Interception Trap (FIT) method to check the changes of species composition and abundance of silphids at Mt. Sokrisan National Park from April to October in 2003 to 2007. A total of9,704 individuals of six silphid species were examined by FIT. Among them, Nicrophorus quadripunctatus was the most dominant species with 8,763 (90.3%) individuals. There were only 971 (9.7%) individuals of the other five species. The seasonal abundance of silphids peaked in July and August. The annual abundance has decreased gradually since 2004. Therefore, the changing patterns of species composition and abundance of silphids checked by long-term monitoring could be used as environmental indicators which indirectly show the environmental changes of Mt. Sokrisan National Park.
Structural property in communities of aquatic insects and benthic macroinvertebrates could reflect the impact of environment on aquatic ecosystems. Benthic macroinvertebrates were collected at 18 different lakes across different levels of environmental impact in Korea. Community responses were analyzed by species abundance distribution (SAD). Rank-abundance (or relative abundance) curves were evaluated by classical SAD (Geometric series, Log-series, and Lognormal distribution) and niche apportionment models (dominance pre-emption, random assortment, random fraction, and dominance decay). Geometric series was more accepted in lakes among classical SAD models. Niche apportionment models were observed in a diverse manner across different level of ecological integrity in lakes. Dominance decay model and random fraction model were frequently fitted to the lakes with higher integrity, while dominance pre-emption and random assortment models tend to be presented in low to middle range in integrity.
Moths were collected using a 22W UV black light trap in June through September in 2005 and May, June, August and September in 2006. The study sites were Namsan (Mt. Nam), Jirisan (Mt. Jiri), Woraksan (Mt. Worak) which are part of the Korean National Long Term Ecological Research (KNLTER). There were two common forest communities, Quercus mongolica and Pinus densiflora. The purpose of this study was to compare species diversity of the major plant feeding Lepidoptera in the two forest types at the regional KNLTER sites. We collected a total of 435 species from the KLTER sites in 2005 and 2006. Abundance of moths was highest at Woraksan (Mt. Worak) followed by Jirisan (Mt. Jiri). The Namsan (Mt. Nam) site had the lowest, with five families (Arctiidae, Geometridae, Noctuidae, Notodontidae, and Pyralidae). Analysis of variance (ANOVA) showed statistically significant differences at sampling date in species abundance as a response variable and at site in species richness as another response variable. Although we expected a distinct cluster with the forest type at each study site, one of ordination analyses, nonmetric multidimensional scaling (NMS), showed distinct clusters with the moth assemblages at each site only but NMS did not show any distinct cluster with the different forest types at each site as we expected.
Benthic macroinvertebrate communities were collected in various streams in agricultural and urban areas in Korea. Community structure and species abundance distribution in benthic macroinvertebrates were comparatively analyzed to reveal ecological states pertaining to the sample sites. Species richness in the total macroinvertebrate communities decreased in the gradient along with increase in the level of pollution. Some selected taxa were present in communities collected in the streams in agricultural areas. The rank-abundance curves were also characteristic in revealing community structure according environmental impact. Patterns of species abundance were efficient in revealing ecological states of the sample sites where physico-chemical indicators may not be easily differentiated in stressful conditions. The feasibility of ecological informatics was further discussed in revealing ecological water quality.
Benthic macroinvertebrates were collected with a Surber sampler in streams across different levels of pollution in Korea. Abundance data in different species were analyzed according to the models used in species abundance distribution (SAD), covering geometric series, log series and log normal model. Different patterns in SADs were observed according to the states pertaining to the sample sites. While the log normal patterns were broadly applied to the collected samples, the other models (e.g., geometric series) were selectively observed. The slopes of rank abundance also accordingly reflected the degree of pollution. Application of the theoretical models was additionally discussed in revealing the states of communities. Efficiency of SADs was proposed in community monitoring in response to stressful conditions in aquatic ecosystems.