• 한국패류학회지
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• 제21권1호
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• pp.65-70
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• 2005

The purpose of this study is to determine the appropriate substrate for larval settlement and spat growth in the purple clam, Saxidomus purpuratus in laboratory culture. Larvae were reared with 3 different types of sediments (mud, sand, and mixed) for 46 days in settlement experiment, and settled spats were further grown in 3 types of sediments for 36 weeks in growth experiment. The density of settled spats in muddy sediments was more than 2 times higher than those in mixed or sandy sediments. But, the average size of settled spats in muddy sediments was smaller than those in mixed or sandy sediments. After 36 weeks of growth period, growth rate decreased as shell length increased. When shell length was less than 2 mm, growth rate in mixed sediments was significantly higher than that in sandy sediments. When shell length was more than 2 mm, there was no significant difference in growth rate among different substrates. Sediment type affected growth rate only when the spats were relatively small (less than 2 mm). Muddy sediments seems better for larval settlement, while mixed sediments is best for spat growth. We suggest the laboratory procedure for enhancing seedling production of S. purpuratus.

• 환경생물
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• 제39권4호
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• pp.536-541
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• 2021

Pantala flavescens is a dominant Odonata species in the rice fields in Korea. To determine the effects of different temperatures on its larval growth and emergence, field and laboratory experiments were conducted. Larval growth was also monitored in mono-cropping and double-cropping rice fields. The growth of larvae was monitored every week by measuring the head width. In the field experiment, no difference was found in larval growth and emergence between the control temperature and +1.9℃ of the control temperature. The larval growth was greater at 23℃ than at 20℃ laboratory temperatures, and no emergence was recorded at either temperature after eight weeks of monitoring. There was a quadratic relationship between larval growth and temperature in an incubator at five temperature regimes of 15, 20, 25, 30, and 35℃. Midseason water drainage caused the extinction of the existing individuals and newly hatched larvae dominated after re-watering in the rice fields. Larval size was greater in double-cropping fields than in mono-cropping fields in late July but the tendency was reversed in early August. The results of this study suggest that temperature warming will directly promote the larval growth of P. flavescens and indirectly influence seasonal growth via changes in water management in rice fields.

• 수산해양기술연구
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• 제45권4호
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• pp.251-259
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• 2009

Swimming crabs, Portunus trituberculatus(Miers) are commercially important off the coasts of Korea, Japan and China. Harvest of swimming crabs has been fluctuated along their distribution ranges. Fluctuations in the interannual harvest of swimming crabs may be correlated with the survival rate during the larval period. The survival rates, intermolt periods, and growth of larval swimming crabs were investigated in the laboratory. Larval swimming crabs are released and undergo development from April to August off the western coast of Korea in the Yellow Sea. Sea surface temperatures off the western coast of Korea during the larval season were used for the laboratory experiments, and ranged from 22 to 26${^{\circ}C}$. Larvae were individually cultured at four different temperatures, 22${^{\circ}C}$, 24${^{\circ}C}$, 26${^{\circ}C}$, and 28${^{\circ}C}$. Zoea molted to megalopa at all temperatures and developed to the first crab stage at 24${^{\circ}C}$, 26${^{\circ}C}$, and 28${^{\circ}C}$. Survival rates from zoea I to the first crab stage increased with increasing temperatures. Intermolt period and the growth rate of the mean carapace length were inversely correlated with temperature. Our research helps understand the changes in survival rate and growth of larval swimming crabs resulting from changing oceanic temperatures. Further, our study suggests that the fluctuations in fishery harvest of swimming crabs off the coast of Korea may be related to changes in larval survival affected by changing ocean conditions.

• 한국양식학회지
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• 제20권3호
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• pp.194-198
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• 2007

Reproductive traits of Palaemon gravieri such as embryo size, number of embryo (fecundity), incubation period, larval development mode, larval development period, larval survival and larval growth were described and compared to analyze the correlation among those traits. Embryo volume is a primary factor determining other ensuing reproductive features. Egg volume was $0.042mm^3$ in the first developmental stage. Embryo volume in P. gravieri was comparatively small which is indicative of great number of embryo (y = 3.0161x + 0.0185 $R^2$ = 0.74 positive isometric relationship) and relatively long incubation period. Larvae survived from zoea 1 to post-larvae and it took 45 days at $22^{\circ}C$. Survival rate of the larvae was rather great in the early stage and thereafter steadily decreased. Daily growth rate of larvae in P. gravieri at $22^{\circ}C$ was 0.0195 mm on average. They grew steadily as time went by. Incubation period was between 10-14 days at $22^{\circ}C$. Larval development mode was almost complete planktotrophic. PNR (point of no return) appeared to be the third day on average. Survival rate of larvae without feeding declined rapidly between 3 and 4 days. Larval development period and stage frequency were 23-30 days and 11 stages which imply prolonged larval period and high mortality. The pattern of brood production followed fast successive parturial pattern. Most ovigerous female had mature ovary when they performed parturial molt soon after hatching (larval release).

• 한국발생생물학회지:발생과생식
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• 제16권2호
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• pp.107-112
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• 2012

Early growth, the rate of yolk sac absorption, and nucleus size in liver parenchymal cells were correlated with the nutritional status of first feeding larval haddock, Melanogrammus aeglefinus. Larvae that successfully began exogenous feeding maintained high growth rates, delayed yolk sac resorption, and had larger hepatocyte nuclear sizes than starved larvae. At 10 days post hatch (DPH) the cumulative mortality in the starved larval haddock group was 100%. The area of the hepatocyte nuclei in starved larvae gradually decreased, reaching its lowest value by 9 DPH. Our results support the current practice of providing the first food supply at 3 DPH. Hepatocyte nuclear size can be used to assess larval haddock nutrition status, and may be a good criterion for assessing the success of transition from endogenous to exogenous feeding.

• 한국수산과학회지
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• 제34권4호
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• pp.378-383
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• 2001

실험에 사용한 성숙한 난소를 가진 산모양깔깔새우 (Metapenaeopsis dalei)는 1999년 8월 11일 충남 외연도 근해에서 새우조망을 이용하여 채집하였다. 산란한 유생을 4개의 염분구간과 3개의 수온구간 및 5개의 다른 먹이 조건에서 사육하여 이들의 생존율과 성장률을 비교하였다. 염분조건에서는 채집지의 염분과 유사한 30과 35에서 생존율이 높았고, 수온 조건에서는 산란 수온$24^{\circ}C$에서 생존율이 가장 높았다. 먹이 조건 실험에서는 식물성먹이에서 생존율과 성장이 동물성을 투여한 실험구보다 높았다.

• 환경생물
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• 제23권2호
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• pp.114-119
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• 2005

실험실 내의 4개의 항온조건$(10^{\circ}C,\;15^{\circ}C,\;20^{\circ}C,\;and\;25^{\circ}C)$에서 연못하루살이 (Cloeon dipterum)유충의 생존율, 생장률, 발달률, 성충 우화율을 연구하였다. 사육 시작 1주 동안 유충의 사망률이 상대적으로 높았으나, 그 이후 안정되는 경향을 보였다. 온도에 따른 생장률 및 발달률로부터 판단하여 볼 때, 유충 생장과 발달의 적정온도는 $20^{\circ}C$와 $25^{\circ}C$사이일 것으로 추정되었다. 우화하기까지 소요되는 유충의 기간은 100일 이내 일 것으로 추정되었다.

• Fisheries and Aquatic Sciences
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• 제8권2호
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• pp.90-96
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• 2005

The larvae of Palaemon gravieri were reared in the laboratory at three different temperature regimes ($15^{\circ}C,\;20^{\circ}C,\;and\;25^{\circ}C$) with the salinity ranges (28-32 psu) to understand how temperature and body size influence survival rate, and growth components (molt increment and intermolt period). The optimum temperature for the highest survival rate was $25^{\circ}C$. The intermolt periods consistently increased with an increase in size and instar number; however, the molt increments at successive instars generally decreased with an increase in size and instar number. The shortest intermolt period and the highest larval growth rate both occurred at $25^{\circ}C$. Thus, the optimum temperature for larval survival and growth rate was found to be $25^{\circ}C$ which was the temperature at which the larvae actually appear in nature.

• 한국환경생태학회지
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• 제25권5호
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• pp.666-672
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• 2011

본 연구는 포식압에 따라 서로 다르게 나타나는 성장률에 대하여 한국산 도롱뇽 유생을 대상으로 이루어졌다. 인왕산에서 채집해온 도롱뇽의 알(난괴)을 포식압 유, 무에 따라 두 그룹으로 나누었다. 포식자 cue로는 버들치의 체취를 이용하였고, 포식압이 존재하는 그룹은 하루 세 번 포식자의 cue에 노출되도록 하였다. 포식자 cue 처리는 알 채집일 다음 날부터 부화 후 1주일까지 하였고, 이후 각 유생의 snout-vent length를 버니어 캘리퍼를 이용하여 측정하였다. 부화 후 1주일부터 2주일 사이의 기간 동안 각 그룹의 유생에게 충분한 양의 실지렁이를 먹이로 제공하였고, 남은 먹이는 제거하였다. 부화 후 2주일이 되는 날 각 유생의 snout-vent length를 다시 한 번 측정 한 후, 각 개체의 성장률을 계산하여 데이터 분석을 하였다. 그 결과 포식자 cue처리를 한 그룹은 그렇지 않은 그룹보다 낮은 성장률을 보였으며, 사망률 또한 높은 것으로 나타났다.

• 환경생물
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• 제22권3호
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• pp.369-375
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• 2004

참게(E. sinensis)의 유생 생장에 미치는 기초적인 환경 및 생물학적 정보를 얻기 위해 본 실험을 실시하였다. 참게 유생을 카드뮴과 수은의 0.1, 0.2, 0.3 ppm농도에 처리하였다. 참게의 생존율과 카드뮴과 수은의 중금속 농도와 양의 상관을 나타내었다. 그런데 96시간 사육시 카드뮴과 수은의 반수치사농도는 유생 단계간 유의한 차이를 나타내었다. 반수치사농도는 카드뮴이 수은보다 높았으므로 수은이 더 치명적이였다. 중금속의 축적은 카드뮴과 수은 모두 메가로파 시기부터 급격히 증가하였다. 따라서 참게의 유생의 생육에서 카드뮴과 수은은 참게 유생의 생존에 치명적이며 생물농축이 일어났다.