• Ocean Science Journal
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• v.43 no.3
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• pp.135-146
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• 2008

The monthly distribution of zooplankton communities in Han River estuary was investigated at two stations from July 1998 to June 1999. Monthly mean abundance of total zooplankton varied remarkably, with the range from 20 $indiv.{\cdot}m^{-3}$ to 19,600 $indiv.{\cdot}m^{-3}$. During the study period, dominant species of zooplankton community were dinoflagellate Noctiluca scintillans, copepods Paracalanus indicus, Paracaanus crassirostris, Acartia hongi, Acartia ohtsukai, and meroplanton cirriped larvae. According to tidal states, relative high abundance occurred at high tide without regard to season. The temporal distribution of abundance implied that the reduced salinity probably limited the zooplankton populations and the fluctuations of salinity were an important factor in the variation of abundance. However, the results of salinity tolerance test shows that the variations in salinity do not directly influence the decrease of abundance. This study shows that the relatively high abundance of zooplankton near high tide seems to be related with the expansion of abundant zooplankton inhabiting Incheon coastal waters through tidal currents.

• Korean Journal of Environmental Biology
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• v.24 no.4
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• pp.337-358
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• 2006

The field survey was conducted weekly from April to October in 2004 and 2005 on the sites along the 5.16 road. Sampling sites were made every 100 m height starting from 250 m altitude of both sides of Mt. Halla along 5.16 Road, which crosses the mountain from North to South. Totally 31,698 individuals of 76 species belonged to 25 families were collected. It was July that showed the largest number of species, as 48 species in the northern sloper 42 in the southern slope, and 22 at the highest site (at an altitude of 750 m), while it was April that showed the smallest as 17 species, 15 and 5, respectively. As for monthly fluctuation, the northern slope and the highest site reached their top in August, whereas it was June in the southern slope. In the analyses of similarity (chord distance) of any pair of temporal communities, the closest pair was between June and July in the northern slope area, between July and August in the southern slope and between July and September at the highest site, respectively.

• Korean Journal of Environmental Biology
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• v.28 no.3
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• pp.143-149
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• 2010

The pathogens and community structure of the fishes in Taehwa river were investigated from March 2007 to January 2009. During the study period, 3,504 individuals belonging to 35 species, 17 families and 9 orders were collected. The numerically dominant and subdominat species were Opsarichthys uncirostris (relative abundance 39.7%) and Hemibarbus labeo (relative abundance 30.9%). There were five Korean endemic species (20.8%) including Squalidus chankaensis tsuchigae, Zacco koreanus, Cobitis hankugensis, Coreoperca herzi, Odontobutis platycephala. The large fishes like Hemibarbus labeo or Opsarichthys uncirostris were gathered around the Samho bridge, sampling site 2 according to a season. The reaction to which two kinds of fish pathogenic virus is all negative and no fish pathogenic bacteria was isolated from 220 individuals. The fish pathogenic parasite not present variously with 7 species. Especially, Trichodina sp. was detected monthly and the infective density was high. But it is cosidered that temporary overcrowding of fish is not influenced mass mortality causing diseases in the specific site of river.

• 한국해양학회지
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• v.19 no.1
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• pp.44-55
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• 1984

Abundances of small fishes that utilized seagrass meadows of Redfish Bay, Texas, were analyzed quantitatively to determine monthly changes of this concentrated subtropical fish community during 1982-1983. an effective quantitative sampler, a 1-㎡ thrown cage, yielded a total of 10,223 fishes that comprised 40 species in 23 families, with average total densities about 15 fishes/㎡ in shoalgrass meadow and 6 fishes/㎡ in turtlegrass meadow. The darter goby, pinfish, code goby, and Gulf pipefish were the four most abundant species, and accounted for approximately 85% of the number of fish collected. However, the two different meadows had different relative abundances of fishes. The darter goby numerically dominated shallower shoalgrass meadow, while the pinfish and code goby were the commonest fishes in deeper turtlegrass meadow. Seasonal changes in both species composition and abundances of fish populations were major characteristics in these subtropical seagrass medows. Peak abundance of total fishes occurred during spring, with a secondary peak in fall. Lowest abundance of total fishes occurred in winter. Each abundant species showed its own seasonal abundance pattern, and had a peak abundance 1-3 months separated from other species, with some overlap of increased larval recruitment. Such distinct seasonal abundance patterns with different times of peak recruitment. Such distinct seasonal abundance patterns with different times of peak recruitment among fish species seem to permit use of the seagrass habitats with reduced, seasonal competition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.141-144
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• 1990

Seasonal change in the reproductive pattern of the marine Cladoceran Podon polyphemoides, was studied using materials collected monthly during the period from January to December 1986 in Yongil Bay, Korea. The relative abundance of P. polyphemoides exceeded $10\%$ of total zooplankton in July. While the species remained as a minor components of the zooplankton community during the other periods of occurrence from June to December. Occurrence of sexual individuals of P. polyphemoides (males and gamogenetic females) in higher proportion in cold months ($30\%$ in November and $40\%$ in December) suggests that resting egg production of this species is largely confined to cold monthis in Korean waters as an overwintering strategy.

• Animal Systematics, Evolution and Diversity
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• v.26 no.2
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• pp.105-114
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• 2010

A study of Han River fish assemblage dynamics for 4 years was conducted. From April 2005 to August, 2008, fishes inhabiting two sites of Han River were sampled for identification. For further analysis, 40 individuals of the dominant species were sampled monthly from March 2006 to November 2008. The fish assemblage at site 1 was dominated by Zacco platypus (32.69%), while the subdominant species were Acheilognathus yamatsutae (14.4%), Acanthorhodeus gracilis (9.43%), Squalidus japonicus coreanus (6.84%), and Tridentiger brevispinis (5.18%). The most abundant species at site 2 was Korean Chub (Zacco koreanus) with relative abundance of 62.45% and followed by Pungtungia herzi (10.29%), Coreoperca herzi (8.67%), and Coreoleuciscus splendidus (6.82%) as the subdominant species. At both sites, the endemics populations show an increasing pattern during the whole survey period, while the natives were declining in the last two years.

• Journal of Ecology and Environment
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• v.31 no.2
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• pp.161-165
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• 2008

This study was performed for the purpose of monitoring monthly levels of two pathogenic microorganisms, Cryptosporidium and Giardia, from November 2005 to August 2007 in Sangsa Lake. Water temperatures, pH and DO fluctuated seasonally at the study site. Annual mean values of BOD, COD and SS were $0.8\;mg\;L^{-1}$, $2.3\;mg\;L^{-1}$ and $1.9\;mg\;L^{-1}$ respectively. Although there was distinct seasonal variation in water chemistry and chlorophyll $\underline{a}$ concentration, the lake generally contains low concentrations of nutrients and chlorophyll $\underline{a}$. The relative abundance of coliform bacteria was always greater than that of fecal coliform. The fecal coliform bacteria comprised $8.5{\sim}22.1%$ of total coliform bacteria. Seasonal analysis of Cryptosporidium and Giardia levels in the study site showed that in winter (November through February), Cryptosporidium oocysts and Giardia cysts were most abundant ($1.1{\sim}1.8\;{\times}\;10\;cells\;L^{-1}$ and $3.8{\sim}5.1\;{\times}\;10\;cells\;L^{-1}$, respectively), while in summer (July through September) the abundance was lowest ($0.0{\sim}0.3\;{\times}\;10\;cells\;L^{-1}$ and $0.9{\sim}2.9\;{\times}\;10\;cells\;L^{-1}$, respectively). Molecular identification revealed two subtypes of Cyrptosporidium parvum in Sangsa Lake.

• Parasites, Hosts and Diseases
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• v.44 no.1 s.137
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• pp.67-72
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• 2006

Anthropophilic Culicoides were investigated in a rural community endemic for Mansonella perstans in Ijebu North area of western Nigeria between December 2003 and October 2004. Three hundred and fifty-nine adults of Culicoides fulvithorax collected by human bait in the morning were dissected for Mansonella perstans larvae, and $1.95\%$of infection rate was found. Seasonal abundance of C. fulvithorax was investigated by monthly biting rates, and showed that higher prevalence was observed in rainy season, with peak in September. Culicoides prevalence was positively correlated with rainfall and relative humidity, but not temperature. Human perceptions on the behavior of these biting midges were determined by interviewing 854 self-selected villagers, of which $86.5\%$ of the interviewees confessed having experienced Culicoides bites. Between 76.5 and $99.1\%$ of the various age groups complained body reactions to Culicoides bites. Itching was the most frequent body reaction. No interviewees associated Culicoides with transmission of any parasitic infections. The results showed need to adequately control Culicoides in the community.

• Korean Journal of Ichthyology
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• v.18 no.3
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• pp.244-250
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• 2006

The ichthyofauna and fish community structure were investigated at five stations in Yeongok stream, Gangneung, during April and December 2005 monthly. During the surveyed period twenty nine species belonging to ten families were collected. Dominant species in number was Zacco platypus (relative abundance : 29.0%) and subdominant was Rhynchocypris steindachneri (12.1%). There were six Korean endemic species including Rhynchocypris kumgangensis. Koreocobitis rotundicaudata and Luciogobius guttatus that were not reported in near streams were collected in Yeongok stream only. Ladislabia taczanowskii was considered as a geographically important species. There were stabilized fish community structure with species diversity index of the community 2.521 in Yeongok stream ichthyofauna.

• Korean Journal of Environmental Biology
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• v.36 no.3
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• pp.424-437
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• 2018

The incidence of freshwater algal bloom has been increasing globally in recent years and poses a major threat to environmental health. Cyanobacteria are the major component of the bloom forming community that must be monitored frequently. Their morphological identities, however, have remained elusive, due to their small size in cells and morphological resemblances among species. We have analyzed molecular diversity and seasonal changes of cyanobacteria in Paldang Reservoir, Korea, using morphological and 16S rRNA pyrosequencing methods. Samples were collected at monthly intervals from the reservoir March-December 2012. In total, 40 phylotypes of cyanobacteria were identified after comparing 49,131 pyrosequence reads. Cyanobacterial genera such as Anabaena, Aphanizomenon, Microcystis and Synechocystis were predominantly present in samples. However, the majority of cyanobacterial sequences (65.9%) identified in this study were of uncultured origins, not detected morphologically. Relative abundance of cyanobacterial sequences was observed as high in August, with no occurrence in March and December. These results suggested that pyrosequencing approach may reveal cyanobacterial diversity undetected morphologically, and may be used as reference for studying and monitoring cyanobacterial communities in aquatic environments.