Feeding Selectivity of Calanoid Copepods on Phytoplankton in Jangmok Bay, South Coast of Korea

장민철,이동섭,노일,신경순 한국해양과학기술원 2010 Ocean science journal Vol.45 No.2

Grazing impacts of calanoid copepods on sizefractionated phytoplankton biomass [chlorophyll (Chl)-a] were measured in Jangmok Bay, Geoje Island, Korea, monthly from November 2004 to October 2005. The ingestion rate of calanoid copepods on total phytoplankton biomass ranged between 1 and 215 ng Chl-a copepod-1 day-1 during bottle incubations. Results indicated that microphytoplankton (> 20 μm) was the primary food source for calanoid copepods in grazing experiments on 3 phytoplankton size categories (< 3 μm, 3-20 μm, and > 20 μm). The ingestion rate on microphytoplankton showed a significant increase (r = 0.93, p < 0.01) with Chl-a concentration. Nanophytoplankton (3-20 μm) showed a negative ingestion rate from June 2005 to October 2005, but the reason is not completely understood. Calanoid copepods were unable to feed efficiently on picophytoplankton (< 3 μm) due to unfavorable size. Calanoid copepods removed between 0.1% and 27.7% (average, 3.6 ± 15.8%) of the phytoplankton biomass daily during grazing experiments. Grazing pressure was high in winter and early spring (January-March: 15.6-27.7%), while low in summer (June-August: -33.1-0.0%) and autumn (September–November: -1.4-5.1%). Results suggest that calanoid copepods play an important role in controlling the biomass and size structure of phytoplankton in winter and early spring.

기수산 요각류 Paracyclopina nana의 대량배양

이균우(Kyun-Woo Lee),최영웅(Young-Ung Choi) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.8

해산 copepod는 어류 양식을 위한 초기먹이생물로 가장 이상적인 것으로 알려져 있으며 최근 이들의 대량배양에 관한 연구가 많이 시도되고 있다. 따라서 본 연구는, 기수산 copepod인 Paracyclopina nana의 대량생산을 위해, 실용화 가능 한 배양방법개발의 일환으로 rotifer 대체를 위한 P. nana의 nauplius 생산법과 Artemia 대체를 위한 P. nana의 C4-성체 생산법 으로 나누어 대량배양을 시도하였다. P. nana의 nauplius 생산 시, 수확된 nauplius는 약 95% 이상이 N1-N2였다. 15일 동안 수확된 nauplius의 일일 평균 생산량은 1, 2차 각각 6.9×106, 7.2×106였으며, 배양수 내의 암컷과 포란한 암컷의 수는 시간이 경과할수록 약간 감소하는 경향을 보였으나 15일 동안 비교적 일정한 개체수를 유지하는 것으로 나타났다. C4-성체의 생산 시, 수확된 copepod의 비율은 C4-수컷, 암컷 및 포란한 암컷이 각각 약 49%, 28% 및 18%였으며 일일 평균 생산량은 1, 2차 각각 8.2×105, 9.0×105 개체였다. 결과적으로, P. nana 대량배양 방법에서 nauplius와 C4-성체의 일정한 생산이 가능하였으며 어류의 입 크기에 따라 배양 방법의 선택에 의해 연속적인 먹이 공급이 가능할 것으로 판단된다. Marine copepods are ideal live prey for fish larvae, and many studies on the mass culture of the organism have been reported. This study performed a mass culture of the brackish copepod Paracyclopina nana containing nauplius and C4-adult production methods. In nauplius production, the harvested nauplii over 95% were comprised of N1 and N2. Daily mean nauplius production of two trials for 15 days were 6.9×106 and 7.2×106 individuals, respectively. The densities of the adult females were maintained at a similar level of the initiation during production. In C4-adult production, the proportion of harvested copepods containing C4-adult males, females and ovigerus females were 49%, 28%, and 18%, respectively. The daily mean nauplius production of the two trials for 16 days were 8.2×105 and 9.0×105 individuals, respectively. As a result, the continuous production of P. nana using the mass production system was successful. Therefore, the continuous and stable feeding for fish larvae in aquaculture would be possible by the selection of the copepod culture method depending on the mouth size of the fish.

수온과 염분에 따른 5종 요각류의 성장과 생산력

이균우 ( Kyun Woo Lee ),박흠기 ( Heum Gi Park ) 한국수산과학회 2005 한국수산과학회지 Vol.38 No.1

N/A This study investigated the productivity and growth of copepods, Sinocalanus tenellus 2 strains, Paracrclopina nana 3 strains, Apocy`clops roil 2 strains, Tachidius triangularis 1 strain and Tigriopus sp. 1 strain at different temperatures (24, 28 and 32℃) under 15 psu and various salinities (10, 20, 30 psu) at 28℃ for an individual culture. And the mass culture was carried out to evaluate the production of these copepods in the 500 mL vessel. For an individual culture of copepod, survival period of a brood female tended to increase with the decrease of temperature, but was not significantly influenced by salinity. With an increase of temperature and a decrease of salinity, maturation period of nauplii in all species tended to decrease. Total nauplii production from a brood female at 24℃ was higher than that from a brood female at either 28 or 32℃ for S. tenellus and at 32℃ than either 24 or 32℃ for A. roil Haenam strain. but was not influenced by temperature for another copepods. And total nauplii production from a brood female at 10 and 20 psu tended to be higher than that from a brood female at 30 psu, expect for Tigriopus sp. and P. nano Hwajinpo strain. Total nauplii production from a brood female was the highest in Tigriopus sp. (350 nauplii) at 28℃ under 20 psu, followed by A. royi Haenam strain (187 nauplii) at 32℃ under 15 psu and P. nana Hwajinpo strain (152 nauplii) at 24℃ under 10 psu. In the mass culture of each copepod, P. nana was the most productive (26.6 mg dry weight) and this value was two and four times higher than productivity of Tigriopus sp. and A. royi, respectively.

Effects of water accommodated fractions (WAFs) of crude oil in two congeneric copepods Tigriopus sp.

Han, J.,Kim, H.S.,Kim, I.C.,Kim, S.,Hwang, U.K.,Lee, J.S. Academic Press 2017 Ecotoxicology and environmental safety Vol.145 No.-

<P>Oil pollution has deleterious effects on marine ecosystems. However, the toxicity of crude oil towards Antarctic marine organisms has not been well studied. We compared the deleterious effects of water accommodated fractions (WAFs) of crude oil on reproduction, intracellular reactive oxygen species (ROS) levels, and antioxidant enzymatic activity in Antarctic (Tigriopus kingsejongensis) and temperate (Tigriopus japonicus) copepods. Reproductive rates of T. kingsejongensis and T. japonicus were significantly reduced (P < 0.05) in response to WAFs. Furthermore, T. kingsejongensis showed elevated levels of ROS and higher antioxidant enzyme (glutathione peroxidase [GPx]) activity than T. japonicus in response to WAFs. CYP genes from congeneric copepods were identified and annotated to better understand molecular detoxification mechanisms. We observed significant up-regulation (P < 0.05) of Tk-CYP3024A3 and Tj-CYP3024A2 in response to WAFs, suggesting that CYP genes may contribute to the detoxification mechanism in response to WAF exposure. These finding also suggest that WAFs may induce oxidative stress, leading to reproductive impairment in copepods. Furthermore, Tk-CYP3024A3 and Tj-CYP3024A2 genes can be considered as potential biomarkers of WAF toxicity in the congeneric copepods T. kingsejongensis and T. japonicus. This study will be helpful for enhancing our knowledge on the harmful effects of WAFs in Antarctic and temperate copepods and provides insight into the underlying molecular mechanisms.</P>

Egg Production Rate of the Copepod Calanus sinicus off the Korean Coast of the Yellow Sea during Spring

강형구,이창래,최근형 한국해양과학기술원 2011 Ocean science journal Vol.46 No.3

The egg production rate (EPR) of Calanus sinicus was measured from March 2007 to April 2010 at three stations along the Korean coast of the Yellow Sea (in coastal waters off Saemangum, Yeongheungdo, and Asan Bay) to estimate in situ maximum egg production rate (MEPR) and to understand whether the females were limited in their growth or fecundity in the field. The mean EPR of C. sinicus at each sampling date ranged from 10.3-34.9 eggs female^(-1) d^(-1) (mean 23.4 eggs female^(-1) d^(-1)), and the EPR of individual copepods ranged from 0-81 eggs female^(-1) d^(-1). The mean EPR was positively correlated with the body weight of female copepods. The MEPR at each sampling date ranged from 40-81 eggs female^(-1) d^(-1) (mean 50.4eggs female^(-1) d^(-1)). Over 84% of eggs spawned hatched successfully. The weight-specific growth rate (WSGR) ranged from 0.038-0.111 d^(-1) (mean 0.082 d^(-1)), indicating that 3.8-11.1% of the carbon in an adult female was produced daily as female growth. The WSGR was negatively correlated with water temperature. The ratio of mean EPR to observed mean MEPR ranged from 20-70% (mean 46%), indicating that ~54% of a female’s growth might be limited in the field. We suggest that the ratio of observed EPR to mean MEPR of copepod can be applied to understand how the copepod responds to environmental changes, as well as EPR and hatching success.

Effects of salinity on growth, fatty acid synthesis, and expression of stress response genes in the cyclopoid copepod <i>Paracyclopina nana</i>

Lee, Seung-Hwi,Lee, Min-Chul,Puthumana, Jayesh,Park, Jun Chul,Kang, Sujin,Hwang, Dae-Sik,Shin, Kyung-Hoon,Park, Heum Gi,Souissi, Sami,Om, Ae-Son,Lee, Jae-Seong,Han, Jeonghoon Elsevier 2017 Aquaculture Vol.470 No.-

<P><B>Abstract</B></P> <P>In marine ecosystems, salinity fluctuations are critical in modulating energy balance, inducing stress proteins, providing reproductive success and affecting the distribution of copepods. Salinity induces osmotic stress in organisms when they are not in their optimal condition and the stressful status increase the energy demand required for osmoregulation, which in turn reflects in all biological processes. Effects of salinity stress on life history traits and tolerance are species-specific. In this study, we used the estuarine cyclopoid copepod <I>Paracyclopina nana</I> to understand the responses towards the hypo (5ppt) and hypersalinity (25 and 30ppt) conditions, and compared that with the control (15ppt). We investigated the life cycle parameters (e.g. growth and fecundity), fatty acid (FA) synthesis, lipid accumulation (as lipid droplets [LDs]) and modulation of heat shock proteins (<I>hsps</I>) in response to salinity stress. As a result, life cycle parameters and FA synthesis, LDs, and modulation of <I>hsps</I> were found highly dependent on salinity changes in <I>P. nana</I>. Particularly, hypersalinity resulted in developmental retardation, reduced fecundity, decreased FA synthesis, a drop in lipid accumulation, and modulation of stress response proteins, suggesting that <I>P. nana</I> devoted increased energy to cope with the osmotic imbalance due to salinity stress in hypersalinity conditions. This finding provides a better understanding of how salinity affects in vivo endpoints and the relevant molecular responses in estuarine copepods.</P> <P><B>Statement of relevance</B></P> <P>We envisage that this manuscript will be helpful to understand salinity-dependent lipid composition changes in copepods and optimize the optimal salinity for the mass culture for this species.</P> <P>Considering the small size (~600μm) of <I>P. nana</I> and its potential as live feeds for finfish larviculture, the present findings have considerable importance for the aquaculture industry.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The P. nana devoted increased energy to cope with the osmotic imbalance due to salinity stress in hyper salinity condition. </LI> <LI> Life cycle parameters and FA synthesis, LDs, and modulation of hsps were found to be highly salinity dependent in P. nana. </LI> <LI> Hypersalinity resulted in in vivo life parameters, a drop in lipid accumulation, and modulation of stress response proteins. </LI> </UL> </P>

Study on the Copepod Ectoparasites of Sebastes melanops (Girard) and Sebastes crameri (Jordan) in Aquarium

( Kae Shik Chun ) 한국환경생물학회 2003 환경생물 : 환경생물학회지 Vol.21 No.4

N/A Abstract - Nineteen rockfishes representing two species in the family Scorpaenidae were collected from Oregon Coast Aquarium in July 2003 and examined for parasitic copepods. The parasitic copepods were taken from the gills of Sebastes crameri and fins of S. melanops. With regard to the prevalence of copepod 22.2% of the fishes were infected by C. uncinata, and 30.0% by N. robusta. Intensity of infections of Clavella uncinata to Sebastes melanops, showed a range of 4 to 6 with a mean of 5.0 per fish while Neobrachiella robusta to S. crameri was 1 to 6 with a mean of 2.7.

Cross-reactivities of mammalian MAPKs antibodies in rotifer and copepod: Application in mechanistic studies in aquatic ecotoxicology

Kang, Hye-Min,Jeong, Chang-Bum,Lee, Young Hwan,Cui, Yan-Hong,Kim, Duck-Hyun,Lee, Min-Chul,Kim, Hui-Su,Han, Jeonghoon,Hwang, Dae-Sik,Lee, Su-Jae,Lee, Jae-Seong PERGAMON 2017 MARINE POLLUTION BULLETIN Vol.124 No.2

<P><B>Abstract</B></P> <P>The mitogen-activated protein kinases (MAPKs) family is known to mediate various biological processes in response to diverse environmental pollutants. Although MAPKs are well characterized and studied in vertebrates, in invertebrates the cross-reactivities of MAPKs antibodies were not clearly known in response to environmental pollutants due to limited information of antibody epitopes with material resources for invertebrates. In this paper, we performed phylogenetic analysis of MAPKs genes in the marine rotifer <I>Brachionus koreanus</I> and the copepods <I>Paracyclopina nana</I> and <I>Tigriopus japonicus</I>. Also in rotifer and copepods, several studies of Western blot of MAPK signaling pathways were shown in response to environmental pollutants, including multi-walled carbon nanotubes (MWCNTs), water-accommodated fractions (WAFs) of crude oil, and microplastics. This paper will provide a better understanding of the underlying mechanistic scenario in terms of cross-reactivities of mammalian antibodies in rotifer and copepod.</P> <P><B>Highlight</B></P> <P> <UL> <LI> Phylogenetic analysis of MAPKs genes was performed in rotifer and copepods. </LI> <LI> Western blot of MAPKs were reproducible upon MWCNTs, WAFs, and microplastics exposure. </LI> </UL> </P>

Identification and molecular characterization of dorsal and dorsal-like genes in the cyclopoid copepod Paracyclopina nana

Jeong, C.B.,Lee, M.C.,Lee, K.W.,Seo, J.S.,Park, H.G.,Rhee, J.S.,Lee, J.S. Elsevier Publishing Services 2015 MARINE GENOMICS Vol.24 No.3

To date, knowledge of the immune system in aquatic invertebrates has been reported in only a few model organisms, even though all metazoans have an innate immune system. In particular, information on the copepod's immunity and the potential role of key genes in the innate immune systems is still unclear. In this study, we identified dorsal and dorsal-like genes in the cyclopoid copepod Paracyclopina nana. In silico analyses for identifying conserved domains and phylogenetic relationships supported their gene annotations. The transcriptional levels of both genes were slightly increased from the nauplius to copepodid stages, suggesting that these genes are putatively involved in copepodid development of P. nana. To examine the involvement of both genes in the innate immune response and under stressful conditions, the copepods were exposed to lipopolysaccharide (LPS), different culture densities, salinities, and temperatures. LPS significantly upregulated mRNA expressions of dorsal and dorsal-like genes, suggesting that both genes are transcriptionally sensitive in response to immune modulators. Exposure to unfavorable culture conditions also increased mRNA levels of dorsal and dorsal-like genes. These findings suggest that transcriptional regulation of the dorsal and dorsal-like genes would be associated with environmental changes in P. nana.

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

Kang, Jung-Hoon,Kim, Woong-Seo,Son, Seung-Kyu Korea Institute of Ocean ScienceTechnology 2004 Ocean and Polar Research Vol.26 No.2

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.