• Korean Journal of Ichthyology
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• v.10 no.2
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• pp.200-206
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• 1998

Several specimens belonging to the family Bothidae were collected by trawls in Kwangyang Bay and off Kadeok Island in March 1996 and June 1998. These specimens were confirmed to be the post-larvae and juveniles of Laeops kitaharae (Smith and Pope, 1906) that have not been reported in Korea. According to the Amaoka's criterion (1972), four specimens belong to the middle metamorphic post-larval stage, one specimen to the late metamorphic post-larval stage, and two specimens to the juvenile stage. The middle metamorphic post-larval stage can be distinguished from the late metamorphic post-larval stage by the characters such as a notch between foreside of the dorsal fin and dorsal region of the right eye, and greatly elongated second spine of the dorsal fin. In the juvenile stage, the intestine was not externally exposed. However, the early metamorphic post-larval stage was not occurred in this study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.616-620
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• 2017

The feeding habits of post-larval Yatabe blenny Parablennius yatabei (2.0-9.8 mm SL) were examined on the basis of 158 individuals collected from June to October in the coastal waters of eastern Jinhae Bay, South Korea. Based on the index of relative importance (IRI), post-larval P. yatabei fed 94.4% on copepods and 5.6% on tintinnids. The preference of post-larval P. yatabei for copepods to other prey items results from ontogenetic changes. The dietary percentage of copepods increased as fish size increased and tintinnids became less important. The feeding rate of post-larval P. yatabei was consistent at all times of day.

• Development and Reproduction
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• v.17 no.4
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• pp.337-343
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• 2013

Post-thawed larval rearing in Pacific oyster Crassostrea gigas was performed to investigate the survival rate with time course in three kinds of larvae cryopreserved. The highest survival rate and larval activity index (LAI) of post-thawed larvae were obtained from the permeation in 0.2 M sucrose and 2.0 M ethylene glycol (EG) at $-1^{\circ}C/min$ in freezing speed showing the survival rates just after thawing of 63.8% in trochophore, 84.1% in D-shaped veliger and 56.3% in early umbo veliger. In post-thawed larval rearing with food supply, the larvae lasted their lives until 24 hours in trochophore, 75 hours in D-shaped veliger and 57 hours in early umbo veliger. The results suggested that each larval stage post-thawed revealed no more further development to subsequent respective stage.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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• pp.83-88
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• 2001

The effect of topical application with 200,400 and 600 $\mu$g/ml 2,4-dichlorophenoxyacetic acid (2,4-D) on the fifth larval stadium of the silkworm, B. mori, was analyzed. Larvae treated during fifth larval stadium enhanced larval, cocoon and adult parameters. The larval period was significantly decreased with increase in silk gland weight at 400 and 600 $\mu$g/ml, male cocoon weight and shel1 weight in all the treated groups and filament length and weight at 200 $\mu$g/ml treated group. Length of the ovariole, eggs per ovariole and hatching percentage increased significantly in all the treated groups when compared with those of the carrier control. This suggests that the plant growth regulator 2,4-D in addition to affecting silk production also affect reproductive performance.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.69-74
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• 2001

The effect of topical application with androstenedione on economic parameters was analyzed following treatment of last larval stadium. The treated larvae showed significantly increased larval weight along with other enhanced larval, cocoon and adult parameters. The larval period was significantly shortened in all the treated groups with increased cocooning percentages cocoon weight and its shell weight in female and filament length, weight and denier in all the treated groups. Hatching percentage increased significantly in dose dependent manner in all the treated groups when compared with the corresponding parameters of the carrier control group. This suggests that androstenedione can be used effectively for commercial silkworm rearing.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.2
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• pp.157-162
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• 2001

The effect of topical application with naphthoxyacetic acid on economic parameters was analyzed following treatment of fifth instar larvae. Larvae treated during the fifth instar showed significant increase in larval weight along with other enhanced larval, cocoon and adult parameters. The larval period was significantly shortened in all the treated groups with increased cocoon and shell weights in male and shell weight in female in 400 ${\mu}g$/ml treated group and filament length in all the treated groups. Fecundity increased significantly in dose dependent manner in all the treated groups, when compared to that of the carrier control group. This suggests that naphthoxyacetic acid, in addition to affecting larval growth, also affect silk production and reproductive performance.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.47-52
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• 2000

The effect of supplementation with potassium nitrate on economic parameters was analysed following treatment of last larval stadium. The treated larvae showed a significant increase in larval weight at 500$\mu\textrm{g}$/ml and silk gland weight in all the treated groups along with other enhanced larval, cocoon and adult parameters. The larval period was significantly decreased in all the treated groups with increased female and male cocoon weights its shell weights filament lengths at 500$\mu\textrm{g}$/ml. The denier was significantly decreased in all the groups. The filament weight moth emergence percentaged length of the ovariole were unaffected. However, eggs per ovariole, fecundity and hatching percentage significantly decreased compared with the corresponding parameters of the carrier control.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.41-45
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• 2000

The effect of topical application with hydrocortisone on economic parameters was analysed following treatment of last larval stadium. The treated larvae showed a significant increase in larval weight at higher concentrations along with other enhanced larval, cocoon and adult parameters. This suggests that hydrocortisone can be used effectively for commercial silkworm rearing. The larvas period was significantly increased in all the treated groups with increased female cocoon weights, its shell weights and male cocoon shell weight at 20$\mu\textrm{g}$/ml treated group. Filament length, weight and denier were increased significantly in all the treated groups. Moth emergence percentage, length of the ovariole, eggs per ovariole, fecundity and rind hatching percentage were unaffected when compared with that of the carrier control group. This suggests that hydrocortisone in addition to affecting larval growths also affect silk crop.

• Ocean and Polar Research
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• v.37 no.1
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• pp.37-47
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• 2015

The effects of low salinity (fertilization success and larval survival) on the limpet Cellana grata were studied at early stages of development using the marine bioassay technique. It was shown that, under normal conditions for development from fertilization to the post veliger stage, the salinity must be not less than 20.0~35.0 psu. However, the fertilization rate and larval survival of C. grata was obviously reduced at 5.0 psu and 10.0 psu, respectively. Mass mortality was estimated to occur at <20.0 psu (48-h $EC_{50}=19.54psu$) and the survival rate of normal veliger larvae decreased with experimental time during exposure. No observed effective concentration (NOEC) and lowest observed effect concentration (LOEC) of post veliger were estimated at 30.0 psu and 25.0 psu, respectively, during 48-h exposure. The tolerance limits of the test species to salinity revealed various concentration ranges of salinity, which may reflect the physiology and ecology of the initial development stages of C. grata. These results demonstrate that reduced salinity is detrimental to the reproductive success and larval survival of C. grata, and if salinity is lowered by natural or anthropogenic sources during spawning, this would lead to decreased reproductive success and larval settlement.

• Journal of Aquaculture
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• v.20 no.3
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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).