• Journal of Aquaculture
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• v.6 no.3
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• pp.159-171
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• 1993

The effects of environmental factors (density, light, temperature) and live food on growth and survival rate of zoea and mysis of fleshy shrimp, Penaeus chinensis, were examined. The percent survival rates at the culture densities of 200 and 300 larvae per liter were significantly higher than that of 500 larvae per liter (p< 0.05). The percent survival rates at the culture densities of 100, 200, 300 and 500 larvae per liter were $90.3^{ab},\;95.2^a,\;94.3^a\;and\;86.7^b\%$ (p< 0.05). The effects of light conditions with diatom premix diet showed that continuous light was the best for the survival rate, $96.5\%$. Natural light and continuous darkness showed the survival rates $79.0\%\;and\;4.3\%$, respectively. On the rearing temperature, the survival rates were $97.3\%\;at\;19^{\circ}C\;and\;96.7\%\;at\;22^{\circ}C$ with little difference but the higher temperature resulted in faster growth. The survival rate was $51.6\%;at\;25^{\circ}C$ thus showing significant decrease compared to $19^{\circ}C\;and\;22^{\circ}C$. At this temperature the growth was also suffered. With regard to dietary value of live food, both the best survival rate and the fastest growth were obtained when 6 mixed species of diatom (A. normaii, C. simplex, N closterium, P. tricornutum, S. costatum and T. weissflogii) were provided. When single species was supplied the best survival rate $(82.1\%)$ was obtained with S. costatum, but the other species resulted in much inferior survival rates $(below\;80.0\%)$ and poor growth.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.3
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• pp.243-250
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• 2011

The effects of food, temperature, salinity, and rearing density on the survival and growth of the swimming crab Portunus trituberculatus, were studied. With regard to food, the larval survival rate to zoea IV was the highest (53.9%) in the mixed feed group (rotifers+ Artemia), followed, in order, by the rotifer, commercial feed, and Artemia groups. The growth of young crabs reared on different diets was the highest in group VI. The survival rate to zoea II at 20 to $30^{\circ}C$ ranged between 77.2% and 83.1%, and was the highest for crab I (17.3%) at $25^{\circ}C$. When young crabs were cultured individually at four different temperatures (20, 25, 30, and $35^{\circ}C$), the growth did not differ significantly at 25 to $30^{\circ}C$, but was higher than at $20^{\circ}C$. The survival rate of larvae to crab I was 12.7 and 11.4% at 25 and 28 psu, respectively, while all of the larvae died at 15 psu. For young crabs, there was no significant difference in growth and survival from 20 to 30 psu. The survival rate decreased with increasing rearing density from zoea I to crab I. Each molting cycle took 1 month from crab I to VIII. Subsequently, the interval increased with growth. The mean body weight of crab XV after 24 months was $428.05{\pm}57.63\;g$.

• Journal of fish pathology
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• v.8 no.2
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• pp.157-164
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• 1995

In order to examine the effects of $O_2$ saturation and pH on gas-bubble disease of blue crab, portunus trituberculatus, zoeal larvae were reared under 5 different concentrations (6.0, 4.0, 3.1, 2.2, and 0.7million cell/cc) of Chlamydomones sp. under natural light for 4days. Observed pH and $O_2$ saturation in the rearing chamber increased drastically from 12 to 18 o'clock with the increasing of Chlamydomones sp. concentrations, but rapidly decreased from 2 to 6 o'clock in the rearing chamber. Gas-bubble disease of zoeal larvae was observed 4hours after starting of experiment at the pH 8.5 and 118% $O_2$ saturated conditions in rearing chamber during the day, and recovered rapidly with the decreasing of pH and $O_2$ saturation at night. Thus, gas-bubble disease of zoeal larvae was repeated with the increased pH($\geq$8.5) and $O_2$ saturation ($\geq$118%) almost every days. Mortality of zoeal larvae was observed when pH and $O_2$ saturations were reached 8.5 and 118% levels respectively, and deteriorated with the increasing of water temperature, pH and $O_2$ saturation.

• Journal of Aquaculture
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• v.6 no.4
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• pp.273-284
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• 1993

Ion concentrations and osmolarities of the body fluid and oxygen consumption of the larvae of the freshwater crab, Eriocheir japonicus under the influence of various salinities and water temperatures were studied. The levels of $Na^+\;and\;Cl^-$ ions in the body fluid of the crab placed in the low salinities (freshwater and $30\%$ seawater) were higher at the low temperature $(16^{\circ}C)$ than high temperature $(30^{\circ}C)$. However, the crab in the high salinity $(90\%\; seawater)$, those ions in the body fluid were higher at the high temperature $(30^{\circ}C)$ than the low temperature $(10^{\circ}C)$ When the zoea larvae were young (first and second stages), the ion concentrations of the body fluid were more affected by salinities and temperatures of the media. The salinity levels of the media more influenced the levels of $K^+$ ions of the body fluid of the larvae than the temperature. The osmolarities of the body fluid of the larvae were almost isotonic when they were placed at $70\%$ seawater $(24.5\%o)$. Oxygen consumption of individual larva was lower in zoea 1 and 2 stages than the other stage larvae. The high oxygen consumption of the larvae was observed at $70\%$ seawater compared to the other salinity levels.

• Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.180-194
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• 2024

Mass mortalities of mud crab Scylla spp. larvae due to pathogenic Vibrio spp. outbreaks have frequently occurred in hatcheries. To overcome this problem, probiotics containing Bacillus subtilis bacteria are applied to inhibit pathogenic ones. We tested different doses of probiotic-containing B. subtilis (10⁸ CFU/g) on the Scylla tranquebarica larvae and investigated the microbiota population, including Vibrio. Water quality, larvae development, and crablet production were also monitored. The recently hatched larvae were grown in twelve conical fiber tanks filled with 200 L sterile seawater, with a salinity of 30 ppt at a stocking density of 80 ind/L. Four different doses of probiotics were applied in the larvae rearing, namely, A = 2.5 mg/L, B = 5 mg/L, C = 7.5 mg/L, and D = 0 mg/L, with three replicates. Next-generation sequencing analysis was used to obtain the abundance of microbes in the whole body of megalopa and the water media for larvae rearing after applying probiotics. Sixteen Raw Deoxyribonucleic Acid samples (eight from a whole body of megalopa extraction from four treatments of probiotics defined as A, B, C, D, and eight from water media extraction from four treatments of probiotic defined as E, F, G, H) were prepared. Then, they were sent to the Genetics Science Laboratory for NGS analysis. Ammonia, nitrite, total organic matter (TOM), larvae, and crablet production were monitored. Based on the Next-generation sequencing analysis data, the Vibrio spp. decreased significantly (p < 0.05) than control test (D) in megalopa-applied probiotics at the doses of 2.5 mg/L (A) and 7.5 mg/L (C) and in the water media for megalopa rearing treated with probiotics at the dosage of 5.0 mg/L (F). Ammonia in the zoea stage in B treatment and TOM in the zoea and megalopa stage in B and C treatments were decreased significantly (p < 0.05). It impacts the higher number of zoea survival in treatments B and C. Finally, it results in a significantly high crablet production in treatments B and C. Therefore, the dosage of 5 mg/L to 7.5 mg/L improves crablet S. tranquebarica production significantly.

• Animal cells and systems
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• v.6 no.2
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• pp.89-93
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• 2002

The first zoeal stage of Macromedaeus orientalis (Takeda et Miyake, 1969) is described and illustrated. Its morphological characteristics are compared with those of other known species of the subfamily Xanthinae. The first zoeas of M. orientalis and M. distinguendus are similar, but they can be distinguished from each other by the characteristic of antenna. The former has a smooth antenna with a rounded tip, while the latter has a serrated antenna with a spinous tip.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.4
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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.

• Animal Systematics, Evolution and Diversity
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• v.9 no.2
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• pp.69-86
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• 1993

The larval stages of Hemigrapsus sanguineus were reared in the laboratory and described with illustrative figures. Five zoeal and one megalopal stages were found in the complete larval development. At 25^{\circ}C.$, the megalopa and the first crab instar were attained in 18 and 31 days after hatching, respectively. The first zoeal larva of H. sanguineus showed the characteristics ~ h i c h coincide with those of the same genus by bearing lateral spines on carapace, B-types of telson and antenna, 1 +5 setae on the endopod of maxillule, and 2 + 2 setae on the endopod of maxilla. Morphological features of H. sanguineus larvae were compared to the previous descriptions of larvae of the same genus and morphological differences among them were discussed.

• Animal cells and systems
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• v.5 no.4
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• pp.275-281
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• 2001

The zoea1 stages of Philyra kanekoi Sakai, 1934 were obtained by laboratory rearing. Three zoeal stages were described and illustrated in detail. Zoeal morphology was compared with those of other described species of the family Leucosiidae. Morphological comparisons with congeneric species revealed that zoeas of P. kanekoi were more similar to those of P. pisum and P. platychira than to other Philyra. The present material could be distinguished from other Philyrinae species by having no dorsal carapace spine, a spinous tip of the antenna, and no chromatophore on the base of a dorsal carapace spine. Within the family Leucosiidae, the zoeas of three Philyra (P. kanekoi, P. pisum and P. platychira) showed the greatest affinities with Leucosia sima and L. pubescens (Leucosiinae), and the number of setae on the basipod of the first maxilliped could be very useful characterisitcs for indentification between Philyra and Leucosia zoeas.

• Animal Systematics, Evolution and Diversity
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• v.23 no.1
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• pp.9-20
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• 2007

The complete larval development of Chiromantes haematocheir was obtained by laboratory rearing. Five zoeal and one megalopal stages are described and illustrated in detail. Morphological characteristics of the larvae slightly differ from those of Lee (1988), especially in the setal presence of mouthpart appendages. Seven sesarminid zoeas (Parasesarma acis, Parasesarma pictum, Perisesarma bidens, Sesarmops intermedius, Chiromantes dehaani, Chiromantes haematocheir, and Nanosesarma gordoni) can be distinguished from each other in characters of the carapace spines, the antennal exopod and the fork of telson. A provisional key is first provided to aid the identification of seven sesarminid zoeas in Korea.