• Korean Journal of Ichthyology
• /
• v.34 no.2
• /
• pp.96-101
• /
• 2022

The egg, larvae, and juvenile development of Platycephalus indicus sampled from Yeosu estuary were conducted. The egg shape of P. indicus is spherical and transparent on the outside, with two perivitelline cavities inside and one oil globule. The diameter of the fertilized eggs were 1.03~1.12 mm (mean =1.08 mm, n =50). The embryos hatched in about 50 hrs 30 mins after fertilization at the water temperature of 20℃. The newly hatched larvae showed a total length of 2.72~3.04 mm (mean=2.93±0.21 mm, n=50). At 5 days after hatching, they were 3.88~4.42 mm (mean=4.11±0.31 mm, n=15) in TL and their yolk was completely absorbed, developing the teeth. They became juvenile 39 days after hatching and reached 10.23~11.95 mm (mean=11.09±0.86 mm, n=5) in TL. At 45 days after hatching, they were 12.01~13.25 mm (mean=12.63±0.62 mm, n=5) in TL, and their body shape and color were similar to those of adult fish.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.45 no.4
• /
• pp.251-259
• /
• 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.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.22 no.5
• /
• pp.317-331
• /
• 1989

Chaenogobius laevis inhabit brackish waters. Adult male protects egg mass laid under the stones. The egg with small oil globule varied from 3.40 to 4.04 mm in diameter. When water temperature is $22.0\~23.0^{\circ}C$, larvae hatched about 113 hours after fertilization. The newly hatched larvae reared for 33 days grow up to 12.10 mm in total length and developed to the jevenile. When larvae length attained about 8.0 mm, jaw bones were more rapidly ossified than vertebrae and cranium.

• Journal of Aquaculture
• /
• v.21 no.3
• /
• pp.125-132
• /
• 2008

Seed production of olive flounder Paralichthys olivaceus was performed in a pilot RAS. The growth of juvenile olive flounder and changes in water quality were monitored for the entire production period. The pilot RAS consisted of 8 circular culture tanks($4.0mD{\times}1.0mH$), 2 trickling biofilters($1.7mD{\times}2.0mH$), 2 protein skimmers ($0.8mD{\times}2.5mH$), and 4 sedimentation chambers($0.7mD{\times}1.5mH$). The culture surface area was about $100.5m^2$ and the actual working volume was about $106.9m^3$. As many as 300,000 fertilized olive flounder eggs were initially distributed into 2 culture tanks with the water temperature at $19.0^{\circ}C$. Live feeds such as rotifers and Artemia nauplii were fed until the 32nd day after hatching, and a commercial diet was fed from the 19th day to the end of the experiment. After 70 days, 150,256 juveniles with a body length of $65.8{\pm}3.9mm$ were produced in the RAS, with a daily growth rate for body length of 4.7%/day. At this time, the final culture density was 1,495 individuals $m^{-2}$, and 13.6 L of makeup water, 0.071 kW of electricity and 0.025 L of diesel fuel were used to produce a juvenile olive flounder. During metamorphosis of the larvae, the TAN concentration increased to 0.99 mg/L, which made the larvae sensitive to result in some mortality. However no more massive mortality occurred at the juvenile stage after metamorphosis even at a TAN concentration of 4.25 mg/L and a ${NO_2}^{-}-N$ concentration of 2.45 mg/L.

• Korean Journal of Ecology and Environment
• /
• v.41 no.1
• /
• pp.104-110
• /
• 2008

The egg development and early life history of Korean endangered natural monument fish, Iksookimia choii, were investigated in 2006. The eggs from the females were obtained by injecting 10 IU $g^{-1}$ of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were $1.1\sim1.3mm$ in diameter and had no oil globules. Hatching of the embryo began about 24 hrs after fertilization under water temperature of $25^{\circ}C$. The newly-hatched larvae were $2.5\sim2.7mm$ in total length (TL), and their mouth and anus were not yet opened. Six days after hatching, the postlarvae were $4.7\sim5.4mm$ TL, and tip of the caudal notochord was flexed $45^{\circ}$ upward. The juveniles stage was reached when all fin-rays were formed at 35 days after hatching, and their total length were $20\sim22mm$.

• Korean Journal of Ichthyology
• /
• v.36 no.2
• /
• pp.129-138
• /
• 2024

This study examines the osteological development of the Pike gudgeon, Pseudogobio esocinus in the cranial, vertebral, caudal, pelvic and pectoral girdle for the purpose of taxonomic and aquacultural studies. Adult Pike gudgeon collected from the Boseonggang River were reared at 18.5~19.5℃ (average 19.0℃). At 5 days after hatching (total length (TL) 4.25 mm), the parasphenoid, dentary, centrum of vertebrae and clavicle began to ossify. At 22 days after hatching (TL 6.33 mm), 36 to 38 vertebrae had ossified. At 42 days after hatching (TL 16.71 mm), the majority of the skeleton had ossified. Pike gudgeon exhibited comparable characteristics to other fishes of Gobionidae throughout its development, although it displayed differences in some areas, such as the caudal skeleton and fin supports.

• Journal of Mushroom
• /
• v.12 no.4
• /
• pp.357-362
• /
• 2014

Pathogenicity of Steinernema carpocapsae GSN1 strain was evaluated against Morophagoides moriutii larvae. In Petridish tests, insect mortality by the nematode was dose dependent, which increased with dose from 5 to 160 infective juveniles(IJs)/larva. Pathogenicity against fourth-instar larvae was higher than the rate of corresponding second- and third-instar larvae, showing 100% insect mortality with the dose of 40 IJs/$4^{th}$ instar larva and 80 IJs/$2^{nd}$ or $3^{rd}$ instar larvae. Lethal concentration values at 50% ($LC_{50}$) of S. carpocapsae GSN1 strain were 4.2 IJs/$2^{nd}$ instar larva; 8.5 IJs/$3^{rd}$ instar larva; and 2.3 IJs/$4^{th}$ instar larva, respectively. The number of nematodes established in M. moriutii larvae after infection increased in the increment of dose and insect developmental stage. The highest number of nematodes was harvested from fourth instar larvae of M. moriutii at a dose of 160 IJs per larva, showing 22.5 nematodes per insect larva. Nematode reproductive capacity was related to insect developmental stage, showing 6,335 IJs/$2^{nd}$ instar larva, 21,660 IJs/$3^{rd}$ instar larvae, and 88,700 IJs/$4^{th}$ instar larvae.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.57 no.2
• /
• pp.153-168
• /
• 2024

Morphological and skeletal development in the cultured threeline grunt Parapristipoma trilineatum was studied from 1.96 to 61.39 mm notochord length (NL) or standard length (SL) specimens (n=360). After two days post-hatching (dph, 2.13 mm NL), the mouth opened, and melanophores formed in the eyes and egg yolk were absorbed. Oli globules were absorbed at 3 dph (2.71 mm NL). The total number of fin rays reached that of adults at 28 dph (10.58 mm SL). During skeletal development, the premaxillaray, dentary, opercle, preopercle, and cleithrum first began to ossify at 6 dph (3.51 mm NL). Ossification of all skeletal elements was completed at 28 dph (14.57 mm SL). The vertebrae began to ossify at 17 dph (5.63 mm SL) and were completed at 28 dph (8.48 mm SL), progressing from cranium to caudal bone. The centrum ossified from the dorsal to ventral direction. Vertebral fusion and separation were found to be common skeletal abnormalities.

• Journal of Aquaculture
• /
• v.18 no.2
• /
• pp.107-114
• /
• 2005

Clownfish are important and very popular fish in the ornamental aquarium industry. Demand for the fish is increasing dramatically. The present study was conducted to verify methods of broodstock management, patterns of spawning, rates of egg hatching and estimates of larval growth fur the saddleback clownfish, Amphiprion polymnus. Spawning occurred 8 times between August 2002 to June 2004 with 2 females and 1 male participating. Fertilized eggs were separated by an adhesive matrix and were oval in shape. The eggs were $2.46{\pm}0.13mm$ in size as measured along the longest axis. The percentage of fertilized eggs was 96.7%. Hatching was observed seven days post-spawning and hatching rate was 85.5%. The sizes of the newly-hatched larvae were $4.58{\pm}0.21mm$ TL (total length). Larvae had an open mouth and anus, and an oval yolk sac. At the 1 st day after hatching, the sizes of the larvae were $4.90{\pm}0.35mm$ TL. The larvae began to eat rotifers after complete yolk absorption. On the 5th day post-hatch, larvae were $5.88{\pm}0.31mm$ TL with complete fins and the survival rate was 48.6%. At 8 days after hatching, a band began to appear on head and back of the larvae indicating the beginning of metamorphosis. Metamorphosis was completed at an average TL of $15.00{\pm}2.12mm$ on the 23rd day after hatching. By the 45th day after hatching, juveniles averaged $22.76{\pm}3.22mm$ TL and survival rate was 28.4%.

• Asian Journal of Turfgrass Science
• /
• v.19 no.1
• /
• pp.17-25
• /
• 2005

Pathogenicity of entomopathogenic nematde, Steinernema carpocapsae Pocheon strain (ScP) was evaluated against different larval stages(2nd, 3-4th and 5th) of Anomis commode and Anomis mesogona(Lepidoptera: Noctuidae) in petri dish and pot. The $LC_{50}$ values were increased in proportion to larval stage of A. commoda and A. mesogona. $LC_{50}$ value of ScP against 2nd instar of A. commoda and A. mesogona was 9.7 and 4.5, respectively. The 2nd instar of both species was also susceptible to ScP in pot test. That is, mortality of 2nd instar of A. commode and A. mesogona was higher representing $72.5\%\;and\;87.5\%$ 5 days later after treatment, respectively, when ScP was applied at the ,ate of 90,000 infective juveniles(Ijs) per $pot(=1\times10^9\;Ijs/ha)$. However, susceptibility was decreased from 3rd instar. Mortality of 5th instar of A. commoda and A. mesogona was $5.0\%\;and\;10.0\%$, respectively, at the rate of 90,000 Ijs/pot. When ScP was applied into pot including mixed larval stages from 2nd to 5th instar(10 larvae far 2nd instar, 10 larvae for 3rd - 4th instars, and 10 larvae for 5th instar) at the rate of 90,000 Ijs/pot, mortality of A. commoda and A. mesogona was $69.2\%\;and\;50.0\%$, respectively.