• Journal of Aquaculture
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• v.12 no.4
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• pp.255-266
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• 1999

The early development, growth, and morphological changes of Tiger puffer Takifugu rubripes are described on the basis of a seres of a series of reared specimens. Detailed o수 the early developmental stages are illusrtated withe special reference to morphological transformation. Egg and sperm of puffer fish Takifugu rubripes were obtained from mature adults under natural conditions, ferilized artificially and incubated in the laboratory. The incubation period of fertilizd eggs was 160 to 180 hours at a temperature of $15.1~ 18.0^{\circ}C$. Larvae were fed successively with rotifer, Artemia nauplii and artificial food for 90 days. The mean total length of newly-hatched larvae was about 2.8mm. Mouth opening occurred on the 1- day yolk-sac larvae and initial feeding was observed on th 4-5 days after hatching . The morphological transitions from the larvae to juvenile and juvenile and juvenile to young stages occurred when fish reached about 10mm in total length(about 30 days after hatching) and about 32mm in total length(about 60days after hatching) , respectively. The coefficient of variation in total length distribution increased with growth. Following the appearance of its peak at the size of about 18mm in total length, the coefficient value declined. Many changes in proportion of the body parts to total length were observed at about 9~10mm and 30~33mm in total length, corresponding to the transformations from larvae to juvenile and from juvenile to young, respectively. Also one big morphological change was observed at about 18mm in total length that divide the juvenile stage into two sub-stages.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.332-337
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• 2018

The Pacific cod Gadus macrocepahlus, lays demersal eggs and the hatching larvae rise toward the surface layer of the ocean to feed. The change in the specific gravity of eggs and larvae was investigated to examine their vertical distribution and movement in the water column. The specific gravities of fertilized eggs and various size classes of larvae were measured using a density gradient apparatus. In total, the instantaneous specific gravity of 146 eggs and 225 larvae were measured. To prevent any disturbance in the gradient water column due to larval movement, 0.004% MS222 was used for anesthesia. Due to their high specific gravity, eggs spawned were deposited over the sea-bed of the spawning ground. The specific gravity of hatching larvae decreased abruptly. However, Pacific cod larvae still had a comparatively high specific gravity at hatching ($1.03655{\pm}0.00146g/cm3$, n=4, mean SL=3.62 mm) and their specific gravities tended to decrease as they grew. The specific gravity stabilized 6 days after hatching ($1.02590{\pm}0.00212g/cm3$, n=15, mean SL=4.67 mm) and the cod larvae were eventually able to float in the water column.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.1
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• pp.180-185
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• 2016

To investigate the feeding habits of Tridentiger trigonocephalus juveniles captured in the intertidal zone of Dodun-ri, Seocheon-gun from the end of May to early June 2012, the gut contents were observed. Feeding incidence of the juveniles increased twice a day, first in the morning and second in the afternoon. The major food organisms of the juveniles (6.5~10.0 mm NL) were composed of copepods (65.4%), amphipods (2.0%), shrimp larvae (14.5%), polychaete larvae (22.6%), and etc. These food items held more than 2 percentage in the dry weight of the total food items.

• Development and Reproduction
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• v.24 no.1
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• pp.63-70
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• 2020

This study aimed to investigate early life of Coreoperca herzi living in Han River and compare morphological differences between different groups during the development in order to provide basic data for relevant taxonomic research. On average, one female individual spawned 541 to 861 eggs (average 701) at once. After 259 hours, the tail broke out of the egg membrane and hatching began. Immediately after hatching, the larvae were average 7.81±0.10 mm (n=5) in total length. 60 days the juvenile was average 35.9±1.30 mm (n=5) in total length. The white spots spread to the rest of the body, rending the same pattern as that on the body of their broodstock fish.

• The Korean Journal of Malacology
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• v.1 no.1
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• pp.5-12
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• 1985

The maturity of gonads, early development of the fertilized egg, spawning period, and morphogenesis of larvae in Limnoperua fortunei were studied from October, 1981 to November, 1982 as on attempt to identify its life cycle. 1) Active motility of its sperm was observed at late May, and matured egg could be found at late June. 2) It was estimated that the spawning was occured from late August. This species was belong to the short-term breeder because it finished its spawning within 20 days. 3) It has free-living trochophore and D-shaped larva stage. The shell lengths of early, middle, and D-larval stage were $140.0{\mu}m$, $167.6{\mu}m$ and $210.0{\mu}m$, respectively. The shell heigths of each stage were $97.3{\mu}m$, $137.6{\mu}m$ and $178.2{\mu}m$, respectively.

• Korean Journal of Ichthyology
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• v.26 no.1
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• pp.17-24
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• 2014

The egg development and early life history of Acheilognathus majusculus which is Korean endemic species from Yeong river were observed under the controlled water temperature, $18.0{\pm}1.0^{\circ}C$. Fertilized eggs are opaque yellow in color and round oval shaped measuring 2.12 (2.08~2.18) mm in length and 1.86 (1.80~1.98) mm in breadth. The number of eggs averaged 72 (40~112) per an oviposition. The eggs of this species began to hatch about forty three hours after insemination and the total length of larvae was 4.23 mm mean. S form moving of larvae were not observed during larval development. The larvae reached at the heterotrophic stage about twenty-five days after hatching. It is estimated that the larvae was comming out from freshwater bivalve since that time in nature. A. majusculus was grew up to be adult stage enough which can be join to new production for three hundred days after hatching with over 67.8 mm in total length.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.478-484
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• 2008

To elucidate the spawning behavior and early life history of Liobagrus mediadiposalis, mature male and female fish were collected from a branch of the Seomjin River. Spawning was induced by injecting hormones, and then the spawning process and development of fertilized eggs, larvae, and juveniles were observed. Observations of spawning behavior showed that the female established a territory and built a spawning nest, and frequently pressed on the upper ventral part of the male to release her eggs. When spawning was finished, the fish supplied fresh water to the egg mass using their pectoral and caudal fins. Hatching began 189 h 20 min after fertilization at $21.5-23.5^{\circ}C$ (mean $22.7^{\circ}C$). The mean total length (TL) of newly hatched larvae was 7.18-7.39 mm (mean 7.31 mm). Their mouth and anus were already open and they had 14+24=38 myotomes. Eighteen days after hatching, the larvae were 12.71-13.79 mm (mean 13.27 mm) in TL and the yolk sac was absorbed completely. At 35 days after hatching, when all the fin-rays had formed, the juveniles were 15.84-17.92 mm (mean 16.33 mm) in TL.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.132-136
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• 1984

This study was conducted to investigate the bionomics of Curculio sikkimensis in Chonnam province from 1981 to 1983. Damage rates of the chestunt were $26.4\%$ in Damyang, $21.1\%$ in Gwangyang, and $12.9\%$ in Seungju. Adults occurred from the mid-July to the mid-September and showed peak from the mid-August to the early-September. Larvae escaped the chestnut from the early-October to the early-November. Overwintering larvae emerged $3.3\%$ in the first year, $22.78\%$ in the second year and continously overwintered $1.67\%$ in the third year. Larvae showed the highest distribution at $1.67\%$ of soil depth during the overwintering. Mortality of overwintering larvae and course of time showed the linearly correlation. Period of each stage was 5.9 days for egg and 17.17 days for pupa. Adult longevity was 9.10 days for female and 7.03 days for male.

• 한국해양학회지
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• v.11 no.1
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• pp.1-8
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• 1976

This work concerns ecological studies on the larvae of the ark shell, Anadara broughtonii(SCHRENCK), in the aea adjacent to Gajyo-do in Jinhae Bay. Marine environmental factors, namely, temperatue, salinity, depth, and tidal current were observed in connection with the larval distributions. Water temperature appeared to be one of the main factors that influence the spawning activity. The numbers of the drifting larvae fluctuated greatly during the study period. The trend, however, was for numbers to be low in early summern, increasing in mid summer, and reaching a peak in late summer, at high bottom water temperature and low bottom salinities. Significantly increased numbers of the drifting larvae were observed during the period in which the bottom water temperatures and salinities were very close to those at the surface. the numbers of the drifting larvae showed a positive relationship with velocities of the water mass within the range of 0∼20 cm/sec. It was also noticed that the drifting larvae were relatively abundant in the area of eddy motion.

• Ocean Science Journal
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• v.40 no.1
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• pp.11-16
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• 2005

Correction factors based on the catch ratios of egg and larval densities in the southern waters of Korea were estimated for anchovy Engraulis japonica. This was undertaken in order to adjust ichthyoplankton data from different sampling methods, gear types and time. Samples were collected during ichthyop1ankton surveys in Korean waters from 1983 to 1994. The ratios for egg densities obtained in vertical tows with a NORPAC net (ring $\Phi$, 45 cm) compared to those obtained in oblique tows with a KOB net (ring $\Phi$, 80 cm) were 0.86 (CV = 0.65), 1.22 (CV = 0.36), and 0.93 (CV = 0.42) for early, middle, and later developmental stages, respectively. The ratios for larval densities for vertical and oblique tows varied depending on size. For yolk-sac and small larvae (< 4 mm), the ratios were 3.08 (CV = 0.45) and 1.98 (CV = 1.34), while those of 4-6 mm, 6-8 mm, and 8-10 mm larvae were 0.44 (CV = 1.31), 0.45 (CV = 1.70), and 0.56 (CV = 2.50), respectively. Ratios of day/night densities for larvae of 4-10 mm lengths were lower (0.01-0.06) in offshore catches than values obtained in coastal areas (0.440.46) and similar values (0.16-0.04) for vertical and oblique tows. Our results indicated that vertical towing is more efficient for sampling early life stages (from eggs to larvae less than 4 mm long), while oblique towing is more efficient for larvae longer than 4 mm due to depth preferences for each developmental stage (e.g., changes in egg buoyancy and vertical migration oflarvae).