• Proceedings of the Korean Aquaculture Society Conference
• /
• 2003.10a
• /
• pp.93-94
• /
• 2003

To investigate the food organisms of the Acentrogobius elongata during the juveniles stage, the stomach contents of fish, captured in the intertidal zone of Chungchongnam-do Sochon-gun Su-myon Dodun-ri between on early in June from the end of May 2000, were observed. Total length of the fingerings of A. elongata was 1.0~3.0cm size, and the participation rate of feeding was 68.6%. Main food organisms were such as copepods, shrimp larvae, polychaete larvae, and these occupied more than dry weight 4%. Copepods among them dominated the most quantitys by average 64.6%, and food organismsms appeared by order of polychaete larvae and shrimp larvae etc.. Therefore, most important food organisms of fingerlings stage of A. elongata were copepods, polychaete larvae, shrimp larvae etc.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2002.05a
• /
• pp.359-360
• /
• 2002

To investigate the food organisms of the Tridentiger trigonocephalus during the juveniles stage, the stomach contents of fish, captured in the intertidal zone of Chungchongnam-do Sochon-gun Su-myon Dodun-ri between on early June from end if may 1999, were observed. Total length of the juveniles of T. trigonocephalus was 5.5mm∼9.0mm size, and the participation rate of feeding was 68.5%. Main food organisms were such as copepods, amphipods, shrimp larvae, polychaete larvae, and these occupied more than dry weight 2%. Copepods among them dominated the most quantitys by average 67.5%, and next, food organismsms appeared much by order of polychaete larvae and shrimp larvae etc.. Therefore, most important food organisms of juvenile stage of T. trigonocephalus were copepods, polychaete larvae, shrimp larvae etc.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2002.08a
• /
• pp.225-226
• /
• 2002

To investigate the food organisms of the Tridentiger trigonocephalus during the juveniles stage, the stomach contents of fish, captured in the intertidal zone of Chungchongnam-do Sochon-gun Su-myon Dodun-ri getween on early June from end of May 1999, were observed. Total length of the juveniles of T. trigonocephalus was 5.5mm∼9.0mm size, and the participation rate of feeding was 68.5%. Main food organisms were such as copepods, shrimp larvae, polychaete larvae, and these occupied more than dry weight 2%. Copepods among them dominated the most quantitys by average 67.5%, and next, food organismsms appeared much by order of polychaete larvae and shrimp larvae etc.. Therefore, most important food organisms of juvenile stage of T. trigonocephalus were copepods, polychaete larvae, shrimp larvae etc.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2001.05a
• /
• pp.565-566
• /
• 2001

To investigate the food organisms of the Chasmichthys dolichognathus during the juveniles stage, the stomach contents of fish, captured in the intertidal zone of Chungchongnam-do Sochon-gun Su-myon Dodun-ri between on early June from end of May 1998, were observed. Total length of the juveniles of C. dolichognathus was 6.5mm ∼10.0mm size, and the participation rate of feeding was 67.7％. Main food organisms were such as copepods, amphipods, shrimp larvae, polychaete larvae, and these occupied more than dry weight 2％. Copepods among them dominated the most quantitys by avergage 65.5％, and next, food organismsms appeared much by order of polychaete larvae and shrimp larvae etc. Therefore, most important food organisms of juvenile stage of C. dolichognathus were copepods, polychaete larvae, shrimp larvae etc.

• Korean journal of applied entomology
• /
• v.47 no.1
• /
• pp.9-15
• /
• 2008

This study was conducted to investigate the seasonal occurrence of chestnut weevil, Curculio sikkimensis. The chestnuts infected by the weevils were collected from Gongju, Buyeo, and Cheongyang in Chungnam Province, Republic of Korea. Investigation was focus on the escape period of chestnut weevil larvae from the fruits, invading time and vertical distribution in soil, survival rates of larvae during overwintering, emergence period, emergence rate, and sex ratio and longevity of adults. For precocious species, larvae escaped the chestnut from the mid-September to the early-October, middle species and slow species, were escaped from the late-September to the mid-October and from the early-October to the mid-November. After escaping from the chestnut fruits all of the larvae burrowed into the soil within 35 minutes. Overwintering larvae inhabited in the range of $0{\sim}48cm$ from the soil surface and highly distributed in the range of $18{\sim}36cm$. The 74.1 % of wintering chamber were distributed within $18{\sim}36cm$ from the surface. Survival rates observed were 38.0% in 1st year, 16.0% in 2nd years, and 2% in 3rd years, respectively. Seasonal occurrence period of C. sikkimensis was from the early-Aug. to early-Oct. and the optimal occurrence period was the early and mid-Sept. Emergence rate decreased to 8.4% in 1st year, 3.6% in 2nd years, and 0.8% in 3rd years, respectively. Sex ratio was showed in the range of 0.51-0.55. It is female biased ratio. Longevity of adults was 9.9 days for female and 8.9 days for male.

• Development and Reproduction
• /
• v.16 no.2
• /
• pp.107-112
• /
• 2012

Early growth, the rate of yolk sac absorption, and nucleus size in liver parenchymal cells were correlated with the nutritional status of first feeding larval haddock, Melanogrammus aeglefinus. Larvae that successfully began exogenous feeding maintained high growth rates, delayed yolk sac resorption, and had larger hepatocyte nuclear sizes than starved larvae. At 10 days post hatch (DPH) the cumulative mortality in the starved larval haddock group was 100%. The area of the hepatocyte nuclei in starved larvae gradually decreased, reaching its lowest value by 9 DPH. Our results support the current practice of providing the first food supply at 3 DPH. Hepatocyte nuclear size can be used to assess larval haddock nutrition status, and may be a good criterion for assessing the success of transition from endogenous to exogenous feeding.

• The Korean Journal of Ecology
• /
• v.20 no.3
• /
• pp.163-168
• /
• 1997

Taxa of the herbivorus insect larvae and their foodplant species were surveyed in a temperate forest of Namhansansung Area, Sungnam City, Kyonggi Province, in 1994-1996 growing season, Sixty two taxa of insect larvae fed on leaves of 18 woody species in 11 families during three growing season. Larvae began to be detected from the mid-April when the leafing time began. The number of larvae taxa reached to the maximum value(32 taxa) early in May, 1994. It was the time that the value of specific leaf area reached to the maximum. It decreased up to 3-4 taxa in the mid-June. Taxa of insect larvae were different year by year even in the same season. Most of larvae fed on various plant species, suggesting that they were generalist or polyphagous species. Fagaceae, Betulaceae, Ulmaceae, Rosaceae. Aceraceae, Ericaceae, Oleaceae and Styracaceae were fed on by many taxa of insect larvae, while Euonymus spp. (Celastraceae). Lindera obtusiloba(Lauraceae) and Symplocos chinensis for. pilosa(Symplocaceae) were mainly fed on by a few taxon.. Erannis, Calospilos and Phigalia were observed to feed on various species, but Illiberis, Pryeria and Chalocosia fed on only Rosaceae, Euonymus spp.(Cerastraceae) and Symplocos chinensis for. pilosa(Symplocaceae), respectively. An unidentified larva was observed only on Lindera obtusiloba (Lauraceae).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.56 no.5
• /
• pp.676-683
• /
• 2023

The development of the egg, larvae, and juveniles of Acheilognathus macropterus from the Wicheon stream of Nakdonggang River was investigated for early life history characteristics. The fish used in the study were collected from Wicheon stream located in Bian-myeon, Uiseong-gun, Gyeongsangbuk-do. The fertilized egg was 1.88±0.09 mm (n=30) in long diameter and 1.34±0.06 mm (n=30) in short diameter. After fertilization at a water temperature of 20℃, the egg took 31 h and 40 min to hatch. Newly hatched larvae had an average total length of 3.92±0.13 mm (n=30) and possessed a yolk sac the mouth and anus were not developed. Twenty days after hatching, the postflexion larvae had an average total length of 8.08±0.29 mm (n=30), with the tail tip fully bent at 45° and began feeding. Thirty-three days after hatching, the number of fin stems reached an integer with an average total length of 15.0±1.08 mm (n=30). In this study, differences in the egg size, hatching time, melanophore development period, and distribution location were confirmed between A. macropterus and allied species.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.1
• /
• pp.132-138
• /
• 2020

Marphysa sanguinea is the most well-known polychaete species with a high economic value. However, this species has a high mortality in the early rearing stage of aquaculture. This study was conducted to find out the optimal substrate size and organic contents for the growth and survival rate of M. sanguinea larvae and juveniles. It was observed that the smaller grain size (<Ø 0.063 mm) and high organic contents (5-10%) induced settlement and reduced settlement time of larvae. Moreover, the growth and survival rate of larvae reached high levels at Ø 0.004-0.016 mm of grain sizes and 5-7.5% of organic contents as advantageous substrates for settlement. The survival rate of juveniles reached over 90% in less than Ø 0.016 mm substrate on 15-day experiment for different grain sizes of substrates. These results indicated that substrate compositions of less than Ø 0.016 mm of sand size and 5-7.5% of organic contents in mud will enhance the productivity of M. sanguinea at the early stage.

• Journal of Korean Society of Forest Science
• /
• v.9 no.1
• /
• pp.45-48
• /
• 1969

The objective of this research was to investigate the seasonal trends in the population of the larvae of the Pine gall-midge in the spring at field. 1. The comparative ratio in the number of larvae of the Pine gall-midge was 100 in early spring, 29 at April 15th and 10 at May 4th. 2. Probably, the seasonal decrease in the number of larvae at field may be due to the gradual rising in the temperature and decreasing the relative Humidity season the experiment was conducted. 3. Water selection method gave best results in collecting the larvae from soil.