• Title/Summary/Keyword: Copepods

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Two New Species of Poecilostomatoid Copepods Associated with the Bivalve Dosinella penicillata in the Yellow Sea

  • Kim, Il-Hoi
    • Animal cells and systems
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    • v.1 no.1
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    • pp.15-23
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    • 1997
  • Two new species of poecilostomatoid copepods, each belonging to the genera Myicola (Myicolidae) and Conchyliurus (Clausidiidae), are described, based on specimens taken from the mantle cavity of the bivalve Dosinella penicillata (Reeve). The host bivalve was collected from the intertidal mud flat near Inchon in the Yellow Sea.

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Copepods (Crustacea) Associated with Marine Invertebrates from New Caledonia (뉴칼레도니아의 해산 무척추동물에 공생하는 요각류(갑각강))

  • Kim, Il-Hoi
    • Animal Systematics, Evolution and Diversity
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    • no.spc4
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    • pp.1-167
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    • 2003
  • Copepods associated with marine invertebrates are recorded from New Caledonia. Included are three new genera and 30 new species which are distributed in the poecilostomatoid and siphonostomatoid genera Anchimolgus (5 new species), Jamescookina (2), Odontomologus (2), Schedomolgus (3), and Scyphuliger (5) in the Anchimolgidae; Pterioidicola n. gen. (1) in the Lichomolgidae; Critomolgus (3), Doridicola (1), Paramolgus (1), and Pachysericola n. gen. (1) in the Rhynchomolgidae; Ruhtra n. gen. (1) in an uncertain family; and Asteropontius (5) in the Asterocheridae. Copepods new to New Caledonia and new host records are also included. Lists of 251 species of copepods known hitherto from New Caledonia and their 163 species of invertebrate hosts are provided, as well.

Seasonal variation of the zooplankton community of Gamak Bay, Korea

  • Moon, Seong Yong;Kim, Hee Yong;Oh, Hyun Ju
    • Korean Journal of Environmental Biology
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    • v.38 no.2
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    • pp.231-247
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    • 2020
  • The seasonal variation in the zooplankton community and hydrographic conditions were examined in three regions (inner, central, and outer regions) of Gamak Bay, Korea. Zooplankton samples were collected over a period of 12 months from January to December 2006. The hydrographical parameters of temperature, salinity, chlorophyll-a concentrations, dissolved oxygen, and chemical oxygen demand were measured. The total zooplankton density varied from 411 to 58,485 ind. m-3, with peaks in early summer. A total of 65 taxa accounted for approximately 86.9% of the annual mean zooplankton density: Noctiluca scintillans (30.9%) Paracalanus parvus s. l.(24.3%), Acartia omorii(11.9 %), Eurytemora pacifica (5.7%), cladocerans (4.1%), cirriped larvae (3.8%), Oithona similis (3.7%), and Pseudevedne tergestina(2.5%). Copepods dominated numerically throughout the year and comprised 54.3% of the total zooplankton. Most of the dominant copepods showed a well-defined seasonal pattern. The density and diversity of zooplankton in Gamak Bay were influenced by the hydrographic environment that was subject to significant spatial and temporal variations. Multivariate statistics showed that seasonal temperature was the most significant predictor of zooplankton taxa, density, and diversity, as well as the density of dominant taxa. Our results suggest that fluctuations in the zooplankton populations, particularly copepods, followed progressive increments in the temperature and COD concentrations.

Feeding Habits of Syngnathus schlegeli in Eelgrass (Zostera marina) Bed in Kwangyang Bay (광양만 잘피밭에 서식하는 실고기 (Syngnathus schlegeli)의 식성)

  • HUH Sung-Hoi;KWAK Seok Nam
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.5
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    • pp.896-902
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    • 1997
  • Feeding habits of Syngnathus schlegeli were studied by using samples collected from the eelgrass bed in Kwangyang Bay, Korea from January 1994 to December 1994. Syngnathus schlegeli was a carnivore which mainly consumed copepods and epiphytal gammarid amphipods. Its diets included small quantities of caprellid amphipods, tanaids and mysids. It showed ontogenetic changes in feeding habits. In its initial feeding stage, copepods were major food organisms. However, gammarid amphipods were heavily selected with the incretment of the fish size. Food availability in the eelgrass bed changed seasonally. Its main food items were changed according to variations of food availability. Copepods were mainly consumed in spring, and gammarid amphipods in summer and fall.

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Feeding habits of juvenile sea perch, Lateolabrax japonicus in tidal creek at Sangnae-ri Suncheon, Korea (순천 상내리 갯골에 출현하는 농어(Lateolabrax japonicus) 치어의 식성)

  • Jeong, Jae Mook;Kim, Hyeon Ji;Ye, Sang Jin;Yoem, Si Dong;Park, Jong Hyeok;Baeck, Gun Wook
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.51 no.2
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    • pp.221-226
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    • 2015
  • During the study periods, total 143 individuals of Lateolabrax japonicus were collected. Body length (BL) range was 2.0-11.8 cm. Empty stomach occurred in 8.4%. The most abundant prey was copepods. Among copepods, Tigriopus japonicus was the most abundant prey appeared 32.1 in %F. Next important prey was shrimps and mysids. The results of analysis in ontogenetic changes, main prey of two small size classes (2.0-3.9 cm, 4.0-5.9 cm) were copepods. Thereafter, copepods percentage was decreased, but shrimps, mysids, fishes percentage was increased by increasing body length from 8.0 cm< size class.

Feeding Habits of Larval Liparis tanakae from the Nakdong River Estuary, Korea (낙동강 하구역에 출현하는 꼼치(Liparis tanakae) 자치어의 식성)

  • Choi, Hee Chan;Huh, Sung Hoi;Park, Joo Myun;Baeck, Gun Wook;Suh, Young Sang
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.48 no.3
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    • pp.368-376
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    • 2015
  • The Feeding habits of larval Liparis tanakae collected from the Nakdong River estuary were studied. L. tanakae [3.8-10.6 mm notochord length(NL)] was a carnivore thatconsumed mainly copepods. Its diet also included small numbers of free-living flatworms (Macrostomida), tintinnids, cladocerans, and polychaetes larvae. To evaluate ontogenetic changes in dietary composition, three size groups were designated: 3-5, 5-7, and >7 mm. Copepods were the most important prey items for all size groups. The smallest size group frequently preyed on polychaete and bivalve larvae, along with copepods. As notochord length increased, the numbers of cladocerans and Macrostomida increased relative to those of polychaete and bivalve larvae.

Density estimation of euphausiids and copepods by using a multi-frequency method

  • Woo Seok Oh;Geun Chang Park;Jung-Hwa Choi;Hyoung Been Lee;Kyounghoon Lee
    • Fisheries and Aquatic Sciences
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    • v.26 no.12
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    • pp.689-697
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    • 2023
  • This study used a multi-frequency acoustic method to assess the density and spatial distribution of dominant zooplankton, euphausiids and copepods, which are representative species of the zooplankton immigrating the sea around Republic of Korea. Acoustic surveys were carried out in the East Sea and South Sea from June 16 to 29, 2017, using the research vessel Tamgu 20th from the National Institute of Fisheries Science. From the results of the acoustic survey, the distribution of euphausiids was relatively higher in the East Sea than in the South Sea. Additionally, although the distribution of copepods was low in all areas, they were abundant in certain areas in the East Sea and the southern area of the Jeju Sea. Euphausiid and copepod density was estimated to be 1.2 g/m2 (CV = 19.1%) and 2.8 g/m2 (CV = 23.5%), respectively.

Biomass Estimation Using Length-Weight Regression for the Freshwater Cyclopoida

  • Hye-Ji Oh;Geun-Hyeok Hong;Yerim Choi;Dae-Hee Lee;Hye-Lin Woo;Young-Seuk Park;Yong-Jae Kim;Kwang-Hyeon Chang
    • Korean Journal of Ecology and Environment
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    • v.57 no.2
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    • pp.111-122
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    • 2024
  • Zooplankton biomass is essential for understanding the quantitative structure of lake food webs and for the functional assessment of biotic interactions. In this study, we aimed to propose a biomass (dry weight) estimation method using the body length of cyclopoid copepods. These copepods play an important role as omnivores in lake zooplankton communities and contribute significantly to biomass. We validated several previously proposed estimation equations against direct measurements and compared the suitability of prosomal length versus total length of copepods to suggest a more appropriate estimation equation. After comparing the regression analysis results of various candidate equations with the actual values measured on a microbalance-using the coefficient of variation, mean absolute error, and coefficient of determination-it was determined that the Total Length-DW exponential regression equation [W=0.7775×e2.0183L; W (㎍), L (mm)] could be used to calculate biomass with higher accuracy. However, considering practical issues such as the morphological similarity between species and genera of copepods and the limitations of classifying copepodid stages, we derived a general regression equation for the pooled copepod community rather than a species-specific regression equation.

Latitudinal Differences in the Distribution of Mesozooplankton in the Northeastern Equatorial Pacific

  • Kang, Jung-Hoon;Kim, Woong-Seo;Son, Seung-Kyu
    • Ocean and Polar Research
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    • v.26 no.2
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    • pp.351-360
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    • 2004
  • To investigate latitudinal variations in the zooplankton community along the meridian line ($5^{\circ}N-12^{\circ}N$, $131.5^{\circ}W$), we measured temperature, salinity, nitrate, chlorophyll-a and zooplankton at depths above 200 m from July $10^{th}$ to $25^{th}$, 2003. For comparative analysis, data of the physico-chemical properties and chl-a were matched to the two sampling depths (surface mixed layer and thermocline depth-200 m) of zooplankton. Latitudinal differences in the mesozooplankton distribution were mainly influenced by divergence formed at a boundary line formed by currents of opposing directions, consisting of North Equatorial Current (NEC) and North Equatorial Counter Current (NECC). High concentrations of chl-a south of $9^{\circ}N$, caused by equatorial upwelling related nutrients, is thought to be affected by the role of this divergence barrier, supported by relatively low concentrations in waters north of $9^{\circ}N$. The latitudinal differences of the chl-a were significantly associated with the major groups of zooplankton, namely calanoid and cyclopoid copepods, appendicularians, ostracods, chaetognaths, invertebrate larvae, and others. And temperature significantly affected the latitudinal variation of radiolarians, siphonophores, salps and immature copepods. The latitudinal differences in the two factors, temperature and chl-a, which explained 71.0% of the total zooplankton variation, were characterized by the equatorial upwelling as well as the divergence at $9^{\circ}N$. The physical characteristics also affected the community structure and abundance of zooplankton as well as average ratios of cyclopoid versus calanoid copepods. The abundance of dominant copepods, which were consistent with chl-a, were often associated with the carnivorous zooplankton chaetognaths, implying the relative importance of bottom-up regulation from physical properties to predatory zooplankton during the study period. These results suggested that latitudinal distribution of zooplankton is primarily controlled by current-related divergences, while biological processes are of secondary importance in the northeastern Equatorial Pacific during the study period in question.

Ontogenetic Food Habits of Four Common Fish Species in Seagrass Meadows (해초생태계에 서식하는 4 우점어종의 성장에 따른 먹이의 변화에 관한 연구)

  • 허성희
    • 한국해양학회지
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    • v.21 no.1
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    • pp.25-33
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    • 1986
  • Ontogenetic food habits of the four most abundant fish species in seagrass neadows of Redfish Bay, Texas, were examined quantitatively during 1982-1983. The darter goby (Gobionellus bolelsoma) and pinfish (Lagodon rhomboides) were trophic generalists, which used a wide range of food items. The darter goby had relatively diverse, omnivorous diet which included amphipods, copepods, polychaetes, filamentous algae, diatoms, and detritus. This species did not show distinct ontogenetic changes in foodpreferences. Unlike the darter goby, the pinfish showed ontogenetic progression of four feeding stages. An initial feeding stage was a planktivorous stage in which copepods were int major food items, followed by a carnivorous stage in which amphipods became the major food items, an omnivorous stage in which filamentous algae, diatoms, amphipods, and polychaetes were the major food items, and finally a herbivorous stage in which seagrass pieces with attached epiphytes and their debris were the major food items. The code goby (Gobiosoma robustrm) and Gulf pipefish (Syngathus scovelli) appeared to be relatively specialized in food havits as carnivorous. Similar ontogenetic changes in food habits were observed for these two species, i.e.initially, copepods were the major food items, followed by a gradual transition to amphipods with growth.

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