• Journal of Environmental Science International
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• v.31 no.11
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• pp.989-992
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• 2022

This study was conducted to investigate the efficacy of larval stages of three species, namely, Tenebrio molitor, Protaetia brevitarsis seulensis, and Ptecticus tenebrifer larvae, in degrading poultry manure, specially, broiler and duck manure. The survival rates of larvae were also noted. For the experiment, T. molitor (n=300), P. brevitarsis seulensis (n=60), and P. tenebrifer (n=300) hatched larvae were randomly divided into six groups with three replicates. The degaradation efficacy tests were then performed for 30 days in a laboratory. The test groups were as follows: T1, 110 g broiler manure + T. molitor larvae (n=50); T2, 110 g duck manure + T. molitor larvae (n=50); T3, 125 g broiler manure + P. brevitarsis seulensis larvae (n=10); T4, 125 g duck manure + P. brevitarsis seulensis larvae (n=10); T5, 105 g broiler manure + P. tenebrifer larvae (n=50); and T6, 105 g duck manure + P. tenebrifer larvae (n=50). The groups showed significant efficacy in degrading broiler and duck manure (p<0.05). The highest survival rates were recorded for T. molitor larvae in both manure types [T1 (92.67%) and T2 (50%)], followed by P. brevitarsis seulensis larvae (T4, 40%) and P. tenebrifer larvae (T6, 14.67%) in duck manure. Next, the survival rates of P. brevitarsis seulensis (T3) and Ptecticus tenebrifer larvae (T5) in broiler manure were 0%. In conclusion, these results point to the feasibility of using insect larvae to degrade broiler and duck manure.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.189-194
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• 2009

To investigate the difference in the ecological niches between Pfiesteria piscicida and Pfiesteria-like species (Cryptoperidininopsis brodyi and Stoeckeria algicida), we have observed the feeding behavior of three potential predators on abalone larvae and measured the survival rates of abalone larvae as a function of initial predator concentration. When the predators were mixed with abalone larvae, P. piscicida and C. brodyi became active and exhibited attacking behavior on abalone larvae within a few seconds. They could ingest whole soft body of abalone larvae using a peduncle. In contrast, feeding and attacking behavior were not observed from S. algicida. Survival rates in abalone larvae decreased with an increase of the initial concentration of P. piscicida and C. brodyi. These results indicate that Pfiesteria and Pfiesteria-like species displaying the very same shape and size have different ecological niche in the marine food webs, which implies that identification to species level is definitely important to understand and discriminate the ecological roles of them.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.220-228
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• 2019

To determine the horizontal and temporal distribution of common squid larvae, Todarodes pacificus (hereafter T. pacificus), we conducted surveys using an IKMT net (mesh size: $500{\mu}m$) with a Fisheries Research Vessel (FRV, TAMGU 21) in the southwestern part of the East Sea in summer (August and September) and autumn (November) 2015. A total of 228 larvae, ranging in mantle length (ML) from 1.4 mm to 21.9 mm, were collected at 35 stations over the research period. The monthly average mantle length of T. pacificus larvae did not differ significantly in August, September and November. (p > 0.05). Catch densities at positive stations ranged between 0.1 and $7.9inds./1,000m^3$ over the research period. Incidence rates of T. pacificus larvae were similar over three months, in the study area (62.9 % - 68.6 %). The 4 - 5 mm mantle length range had the highest frequency in size-frequency distributions for T. pacificus larvae. The larval survival temperature ($15-24^{\circ}C$) at positive stations for catch densities was located below a 20 m depth in August whereas it was located at the surface of the water in September and November. The survival temperature for larvae existed from the bottom to the surface of the water where larvae were sampled larvae in shallow sea areas. However, the larval survival temperature occurred in a shallower location than the upper layer of the thermocline in deep sea areas at a depth below 100 m.

• Journal of Practical Agriculture & Fisheries Research
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• v.13 no.1
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• pp.115-129
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• 2011

This study was performed to investigate the effects of food organism and water quality on the mass production of larval red marbled rockfish, Sebastiscus tertius. When rotifer cultured with different food stuffs were supplied to the larvae, rotifer cultured with concentrated Chlorella provided the highest in total length 11.9 mm and survival rate was the highest by 47.0% fed that cultured with ω-yeast Growth and survival rate of larvae fed on enriched rotifer with ω-yeast and super selco, super selco of enriched treatment showed that the best results not only growth but also survival rate. For instance of Artemia, the growth was not significantly different with other treatment but the survival rate was significantly higher than others. The growth of larvae fed with different diets indicated that rotifer+Artemia+commercial diet treatment was the highest on the total length and body weight 18.40 mm and 18.1 mg, respectively, whether the survival rate was rotifer+Artemia treatment was the highest as 57.5%. The most effective density of Chlorella was 10×10⁵ cells/ml for growth of larvae. That density showed that total length and body weight were 11.83 mm and 14.3 mg, respectively. The survival rate was the most effective for 20×10⁵ cells/ml of Chlorella density. That density represented the highest survival rate as 54.5%. Comparing of PSB adding effect, PSB density 15×10⁵ cells/ml was the most effective for growth of larvae and but for survival rate PSB density 10×10⁵ cells/ml was the highest as 61.0%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.3
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• pp.145-149
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• 1988

The effects of temperatures, salinities and diets on the larvae of the fresh water prawn, Macrobrchium koreana were studied. Survival rates were decreased with increasing salinity concentrations, and the second larval stages were almost died in 48 hours in over $40\%$ sea weter$(13.7\%)$. The intermolt duration of the each stage were shortend with increasing water temperature, and the optimum temperatures of the larvae were from $22^{\circ}C\~26^{\circ}C$ The larvae fed with the meat of Tapes japonicus showed the highest survival rate. When the larvae were fed with the eggyolk powder, all the lauvae died before fourth zoea. Under starved condition moltings were continued up to third zoea.

• The Korean Journal of Malacology
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• v.19 no.1
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• pp.19-24
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• 2003

Artificial spawning, larval and spat developments of the bay scallop, Argopecten irradians, which was transplanted from China on 16 August 1996, were investigated monthly until August 1997 in the Deukyang Bay, Jangheung-gun, Jeollanam-do, Korea. Sufficient amount of cultured microalgae supplemented seawater were supplied as food (6 kinds of phytoplankton) for fully grown adult individuals at 17.1-23.2$^{\circ}C$ for 44 days. A total of 45,320,000 eggs were spawned by way of 2 times of artificial spawning inductions such as exposure stimulus to the air and thermal shock (with water temperature) on 29 January and 31 January in 1997. Artificially fertilized eggs were developed to D-shaped larvae (77.5 ${\times}\;63.8\;{\mu}m)$ and metamorphosed to larvae (191.8 ${\times}\;181.2\;{\mu}m)$ 181.2 m) in the attached larval stage on the collectors. A total of 110,000 spats (average 3.04 mm in shell length) were produced at 22.8-26.3$^{\circ}C$ and 31.0-34.4 psu in the indoor rearing tank from 14 February through 7 May in 1997. In case of Argopecten irradians, if the attached larvae in the attachment stage are detached from the collector, they could not live. Accordingly, it is assumed that survival (%) of the attached larvae of A. irridians showed very low because of weak power attached to the collector due to the small number of the byssuses of the attached larva, not the short attachment period by the byssus as seen in other scallops such as Argopecten balloti.

• Journal of Aquaculture
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• v.17 no.3
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• pp.221-227
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• 2004

In the present study, we investigated the effects of food and salinity on growth and survival of river puffer, Takifugu obscurus offsprings in indoor land-based tank during the early development. In the food experiment, the river puffer larvae (TL 8.7$\pm$0.1 mm, BW 20.0$\pm$3.2 mg) were fed with tubificid, Limnodrilus gotoi, water flea, Daphnia carinata, mysid, Neomysis awatschensis, Manila clam, Ruditapes philippinarum and artificial food together Artemia nauplii for 30 days, and the growth and the survival of larvae were investigated. In the salinity experiment, the river puffer larvae and juvenile at three stages (Stage I: TL 5.8$\pm$0.4 mm; Stage II: TL 12.0$\pm$0.2 mm, Stage III： TL 44.5$\pm$0.7 mm) were supplied with Artemia nauplii, water flea and/or artificial food and were reared in 0, 10, 20 and 30 psu at respective stages. The results shows that the growth rates of larvae feeding with artificial food and tubificid together Artemia nauplii were higher than those of larvae in other groups, but the survival rates of larvae feeding with water flea and mysid together Artemia nauplii were higher than those of larvae in other groups. In salinity, the results shows that the growth and survival rates of offsprings were significantly higher in 10∼20 psu than those in 0 and 30 psu at Stage I and n. At Stage III, the growth and the survival rates were the highest in 20 psu, but the lowest in 0 psu. However, it should be noted that the rates in 0 and 30 psu were significantly enhanced at Stage III in comparison with those at Stage I and II. Therefore, it is concluded that river puffer, T. obscurus is euryhaline marine species, which can normally grow and live at salinities from 0 to 30 psu, and that a combinative supplement with Artemia nauplii and water flea, D. carinata may confer an advantage on growth and survival of the river puffer offsprings in indoor land-based tank.

• 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 $428.05{\pm}57.63\;g$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.567-573
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• 1998

Cold storage of concentrated food phytoplanktons is a useful technique in supplying food organisms for artificial shellfish seed. One month after preservation at $4^{\circ}C$, we have measured survival rate of the concentrated food phytoplanktons, Pavlova lutheli, Isochrysis galbana, Isochrysis aff, galbana and Chaetoceros calcitrans. Thereafter we determined survival rate of oyster lavae fed fresh and concentrated diets and fatty acid compositions of the fresh and concentrated food phytoplanktons. Survival rate of concentrated planktons ranged from $23\%$ to $31\%$ after one month at $4^{\circ}C$. The survival rate of oyster larvae fed cold stored food appeared generally higher than those fed fresh harvested food. Especially, the highest survival rate were found in the larvae fed cold stored concentrated I. aff. galbana. EPA and DHA increased after cold storage and the highest level of DHA was detected in I. aff. galbana. As DHA can role as an important factor in determing nutritional value, it would be better to use concentrated I aff, gaibana kept in cold refrigerator for oyster seed production.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.296-306
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• 2019

BACKGROUND: Temperature is known to be the main factor affecting development, growth and reproduction of organisms and also a physical factor directly related to insect survival. Insects as ectothermal species should be responsive to climate changes for their survival and develop various survival strategies under the unfavorable temperature such as low temperature. The purpose of this study is to identify genes contributing to adaptation of low temperature. METHODS AND RESULTS: To identify genes contributing to adaptation of low temperature, the transcriptomic data were obtained from fat body in Plutella xyostella larvae via next generation sequencing. We identified structural proteins, heat shock proteins, antioxidant enzymes, detoxification proteins, and cryoprotectant mobilization and biosynthesis-related proteins. Genes encoding chitinase, cuticular protein, Hsp23, chytochrome protein, Glutathione S transferase, and phospholipase 2 were up-regulated under low temperature. Proteins related to energy metabolism such as UDP-glycosy ltransferase, trehalase and trehalose transporter were down-regulated. CONCLUSION: When insect pests were exposed to low temperature, changes in gene expression of fat body could provide some hints for understanding temperature adaptation strategies.