• Fisheries and Aquatic Sciences
• /
• v.10 no.2
• /
• pp.86-92
• /
• 2007

Adult Dungeness crabs are restricted primarily in the lower part of Glacier Bay, Alaska, but the interaction of larval dispersion and adult distribution is unknown. To understand the larval occurrence in the upper part of Glacier Bay, Dungeness crab larvae, sea surface temperature (SST), and sea surface salinity (SSS) were collected at 16 near-shore and 12 mid-channel stations in Glacier Bay, southeastern Alaska during six sampling periods from March through August 2000. Each station was visited from one to five times during the entire sampling period. Geographic Information System (GIS) was used to contour SST and SSS distribution in Glacier Bay. Seven to 27 stations were visited during each sampling period. Most larvae (85% were zoeae I) occurred during May 31 to June 14, 2000. Larval density varied from none to $51.4\;100\;m^{-3}$ between stations. A few later stage larvae occurred during later sampling periods. Overall, no relationship between larval densities, and SSS, and SST existed. Larvae occurring in the upper bay were probably transported by tidal currents from the lower bay; adult Dungeness crabs in Glacier Bay have a relatively high density near the mouth of the bay but decrease sharply around 40km north of the mouth. The lack of adult crabs in the upper 60km of the bay may be related to lower salinity, resulting in sharp haloclines, or colder temperatures which are not conducive to survival or growth of either larvae or adults.

• Korean Journal of Environmental Biology
• /
• v.22 no.3
• /
• pp.369-375
• /
• 2004

This experiment was studied to obtain basic environmental effects and biological information on the early growth of larval mitten crab (Eriocheir sinensis). Mitten crabs were maintained for each larval stage with solutions containing 0.1, 0.2, and 0.3 ppm of cadmium (Cd) and mercury (Hg). The relationship between survival rate of mitten crabs and metal content in the growth chamber showed a positive correlations. However, it showed a significant difference in the 96 $hr- LC^{50}$ values of Cd and Hg for the E. sinensis larvae from the first zoea larva to juvenile. Hg was more toxic to E. sinensis larval than Cd. When Cd and Hg are released into the water, they enter E. sinensis larval and are biological magnified. These results of survival rate and bioaccumulation are very important when considering the survival of the mitten crab.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2001.05a
• /
• pp.319-321
• /
• 2001

Supply of ntrition-balanced feed is very important for growth of fish, especially for growth of early period of fish. Therefore, most of commercial feeds for larval and juvenile fish are relatively expensive due to high level of the several nutrients to satisfy their requirements for growth. Overfeeding larval fish may increase fish production cost because of larvae feeds high price and deteriorate water quality, eventually reduce growth of fish. (omitted)

• Korean Journal of Environment and Ecology
• /
• v.25 no.5
• /
• pp.666-672
• /
• 2011

This study examined the different growth rate of larval salamander Hynobius leechii by the predation risk. We collected salamander's eggs from Mountain Inwang. Eggs were treated by two different conditions: (1) cue - which had a predation risk three times a day; (2) no cue - which had no predation risk. Predation risk was conducted by using chemical cue from Chinese minnows. The chemical cue treatment started from the next day after the collection and ended one week after the hatching. Between the first week and the second week after the hatching we fed salamander larvae with tubifex ad. libitium. After the treatment phase, we measured snout - vent length of the each larva on the first week and the second week after the hatching. The results showed that there was a significant difference in the growth rate by the predation risk. From these results we found that predation risk can cause the different growth rate to the larval salamander and these changes could be affect their mortality.

• Journal of Aquaculture
• /
• v.11 no.3
• /
• pp.345-352
• /
• 1998

The effect of starvation on the growth and hepatocyte nuclear size of larval rockfish Sebastes schlegeli and spotted sea bass Lateolabrax sp. were studied. The growth of total length and wet weight in both rockfish and spotted sea bass starved were lower than their control counter-parts. The nuclei sizes of parenchymal cells in the liver of rockfish and spotted sea bass were correlated with the nutritional status of their first-feeding larvae. The result suggested that hepatocyte nuclear size in rockfish and spotted sea bass could be used as an alternative indicator for the identification of starving condition and such karyometry might be criteria for evaluating the successful transition from endogenous to exogenous feeding regime.

• Journal of Aquaculture
• /
• v.17 no.1
• /
• pp.58-61
• /
• 2004

Larvae of Pandalus gracilis were reared in the laboratory under controlled conditions (salinity, 32.5∼34.5; photo-periods, 12L: 12D). The experiments were designed to examine effects of temperature (10 and 2$0^{\circ}C$) on larval development, survival, intermolt period and larval growth. The higher survival rate was obtained at 2$0^{\circ}C$ than at 1$0^{\circ}C$ and larvae reached later stages at 2$0^{\circ}C$. Intermolt period increased significantly with increasing of instar number and was longer at 1$0^{\circ}C$ than at 2$0^{\circ}C$.

• Fisheries and Aquatic Sciences
• /
• v.8 no.2
• /
• pp.90-96
• /
• 2005

The larvae of Palaemon gravieri were reared in the laboratory at three different temperature regimes ($15^{\circ}C,\;20^{\circ}C,\;and\;25^{\circ}C$) with the salinity ranges (28-32 psu) to understand how temperature and body size influence survival rate, and growth components (molt increment and intermolt period). The optimum temperature for the highest survival rate was $25^{\circ}C$. The intermolt periods consistently increased with an increase in size and instar number; however, the molt increments at successive instars generally decreased with an increase in size and instar number. The shortest intermolt period and the highest larval growth rate both occurred at $25^{\circ}C$. Thus, the optimum temperature for larval survival and growth rate was found to be $25^{\circ}C$ which was the temperature at which the larvae actually appear in nature.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.3 no.1
• /
• pp.83-88
• /
• 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
• /
• v.3 no.2
• /
• pp.157-162
• /
• 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.

• Journal of Sericultural and Entomological Science
• /
• v.37 no.2
• /
• pp.121-126
• /
• 1995

The effects of oral application of fenoxycarb, the commercial formulation Insegar, to the selected developmental stages of the silkworm, Bombyx mori, was investigated. An oral application of the chemical to the silkworm from the 2nd- to the 5th-instar larvae delayed the larval development upto more than 40 days and increased the larval body weight in the range of 1.1 to 1.7 folds. When the chemical was orally applied to the final instar larvae, spinning and pupation were prevented, and consequently permanent larvae occurred. The weight of a cocoon and its shell of silkworm(bombyx, mori, L) increased following the application of fenoxycarb to the 2nd- and the 3rd-instar larvae.