• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.4
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• pp.241-250
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• 1992

This study was covered the amount of food consumed per day as well as methods estimating the daily food consumption per fish of Agrammus agrammus in natural population to understand flow of food organisms among trophic levels in bio-community of the coastal waters, Shinsudo, Samchonpo. The estimating formulas were induced from the mathematical models that representing the diurnal fluctuation of the stomach fullness of the fish. The daily food consumption could be estimated by both feeding rates and gastric evacuation rates, but it was more reasonable method that based on gastric evacuation rates than feeding rates. The daily food consumption in wet weight per fish by gastric evacuation rates were 1.9856g/day, 3.4725g/day, 4.4418g/day, 5.8168g/day, and 7.2113g/day in the order of age groups from 0 to 4. The daily rations as percentage of body weight were $9.35\%,\;6.65\%,\;5.76\%,\;4.72\%\;and\;5.31\%$ in the order of ages. The daily food consumption was proportional to the body weight of fish, but the daily food consumption per specific body weight was reciprocal to the body weight. Annual food consumption in wet weight. per fish by gastric evacuation rates were 529.98g from the age of 0.25 to 1.0, 1,269.28g from the age of 1.0 to 2.0, 1,622.76g from the age of 2.0 to 3.0, 2,125.57g from the age of 3.0 to 4.0, 1,316.09g from the age of 4.0 to 4.5 The amount of food consumed per fish during 4.25 years, from the age of 0.25 to 4.5, was 6,863.68g in wet weight. the relationships between the daily food consumption(Dr) by gastric evacuation rates and the total length(L, cm) or the body weight(W, g) were as follows: $$Dr=0.036L^{1.702}$$ $$Dr=0.254W^{0.664}$$

• Journal of Aquaculture
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• v.11 no.3
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• pp.401-419
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• 1998

The structure of benthic algal flora and feeding behavior of sea urchins (Anthocidaris crassispina and Hemicentrotus pulcherrimus), were investigated from the eight different locations along the coast of Cheju Island, Korea. Biomass distribution and dominance of the algal communities were studied in relation to the gut contents and population parameters of the sea urchins. As a result, although the largest algal biomass and biological characteristics of sea urchins, such as test diameter, test hight, body weight, gonad weight, etc. This inhdicated that sea urchins would not be dependednt sorely on the abundance of algal foods, and they might feed on other food items. In order to know such a trend with regard to food selectivity, the diets consumed by sea urchins were analyzed, and it was found that they were composed of benthic and drifted algae, various animal components (sponges, bryozoans, crustaceans, and various unidentified capsulated eggs, etc.) and biets turned out to be smaller than might be expected, and it is postulated that sea urchins were not likely to be the major grazing animals for the formation of algal bed and also canopy deterioration, so-called "white incrustation."

• 한국해양학회지
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• v.27 no.4
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• pp.268-276
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• 1992

Multitrophic interactions among gelatinous planktivores, zooplankton, and phytoplankton were in vestigated in Reeves Bay. New York from mid-March to July in 1989 to evaluate the top-down effect by gelatinous macrozooplankton on the Gyrodinium aureolum bloom through cascading tropic interactions. Zooplankton abundances reached maximal density following a decrease in gelatinous macrozooplankton (hydromedusae and scyphomedusae) abundances, and phytoplankton biomass was low at this time. Subsequently, as ctenophore populations increased zooplankton abundances decreased sharply, and the cell concnetration of G. aureolum began to increase. This field observation supports that the top-down control by gelatinous macrozooplankton on grazers, resulting in low grazing pressure on phytoplankton, can cause an algal bloom. The minimal zooplankton grazing measured using /SUP 14/C tracer technique during the bloom period indicated that zooplankton did not prefer G. aureolum as a good source.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.343-349
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• 2010

The golden apple snail was introduced to the Korea from Japan as a potential food for people in 1983. It is one of the pests of direct-seeded rice in korea. This study was conducted to investigate rice(Oriza sativa) consumption and the extent of damage by the golden apple snail(Pomacea canaliculata) in direct-sown paddy fields. Food consumption of the golden apple snail was highest at $30^{\circ}C$. When the emergence of the 1st, 3rd, and 5th leave of rice supplied food, the consumption of young(shell height 15mm) and adult golden apple snail(over shell height 30mm) at $30^{\circ}C$ were 19.0/79.8, 11.0/54.5, 5.5/18.5, and 0.0/2.0 individuals, respectively. Young rice seedings(before 5th leaves of rice) are very susceptible to golden apple snail damage because the young, tender leaves and stems favor the snail's feeding habits. The field experiment with four treatments (0, 2, 5 and 10 individuals respectively per 10 $m^2$) was carried out. The most serious yield loss was 16% from the plot with 10 adults released at emergency stage of rice.

• Journal of Aquaculture
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• v.1 no.1
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• pp.1-11
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• 1988

There are many problems to be solved for the establishment of more feasible and simplified method of seed production of marine fishes. One of the most important tasks in seed production is to clarify the feeding ecology of larvae and juveniles under. rearing conditions. In the present study, two groups of postlarvae-juveniles of the flounder, Paralichthys olivaceus were used. One ranging 11.38 to 17.08 mm in mean total length was fed with Artemia nauplii at two different water temperatures (19 to $21^{\circ}C$ and 24 to $25^{\circ}C$) and the other ranging 4.39 to 10.64 cm in mean total length was fed with prepared diet. Time required from the start of feeding to satiation was 45 to 55 minutes at 24 to $25^{\circ}C$ and nearly one hour at 19 to $21^{\circ}C$. Mean numbers of Artemia nauplii in digestive tract were 236 to 375 individuals per fish at 24 to $25^{\circ}C$. The amount of food remained in the intestine was $24.8\%$ of the total food in the digestive tract. In juveniles of 4.39 to 10.64 cm in mean total length, amount of prepared diet consumed at satiation was 0.04 to 0.46 g per fish. Digestive tract index in juveniles was rapidly decreased for 24 hours after satiation and kept nearly constant after 48 hours, showing that the time to completely digest the prepared diet in juveniles was estimated to be about 48 hours.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.1
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• pp.85-93
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• 2013

The amount of salted food waste and non-salted food waste from household consisted of 4 family members was surveyed. And the feeding rate and growth rate of Eisenia fetida population upon the different food wastes such as vegetables, grains, fruits and salted food waste were investigated. Total amount of food waste from a household was 3,200g/week. i.e. 0.114kg/day/capita and non-salted food waste was 53.9% of food waste. Salt contents of vegetables, grains, fruits were 0.60, 0.36 and 0.33%, respectively, if they were assumed to have 70% water content. Salt content of salted food waste was 0.78%. Upon the non-salted vegetables and fruits, feeding rate of earthworm was high but growth rate was low. Upon the non-salted grains, feeding rate of earthworm was low but growth rate was high. Upon the food with 70% water content, earthworm could not feed and grow when salt content of food was over 0.6%, and earthworm could feed normally but showed low growth rate when salt content of food was 0.3%. These results indicated that earthworm could stabilize the non-salted food wastes with ease but could hardly stabilize the salted food wastes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.25 no.4
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• pp.160-172
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• 2020

To understand on-site feeding traits of Noctiluca scintillans with unprecedented high abundances around Dokdo in spring, 2014, the composition and abundance of food items in the digestive vacuole of the species were analyzed. Abundances of N. scintillans ranged from 4,328~17,791 inds.m^-3 around Dokdo during the study. The incidence of preyed items in the vacuole of N. scintillans ranged by averaged 32% (24~50%) in the surface waters around Dokdo. Diverse preyed items consisted of fecal pellet, protozoans, pollen, diatoms, dinoflagellates, copepods and ichtyoplankton, while fecal pellets were dominantly fed by N. scintillans (43%) and next by protozoans (19%), pollen (18%), diatoms (7%) and dinoflagellates (4%). Fecal pellet, protozoans and pollen were relatively preferred by N. scintillans compared to diatoms, dinoflagellates and ichtyoplankton based on the incidence in the food vacuoles. Present results indicated that high abundance of N. scintillans found around Dokdo was likely associated with non-phytoplankton items rather than previously well-known diatoms as prey during the study.

• Journal of Aquaculture
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• v.18 no.1
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• pp.13-18
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• 2005

This study was to investigate the effects of water temperature and food on the mass seed production of larval parrot fish, Oplegnathus fasciatus. Growth of the larvae reared at heated water temperature ($25.3^{\circ}C$) was significantly higher than that of the larvae reared at natural water temperature ($20.5^{\circ}C$). In addition, survival rate of the larvae at heated and natural sea water temperature were $24.0\%$ and $12.3\%$, respectively (P<0.05). Growth and survival rate of the larvae fed mixed diets of Nannochloropsis oculata, rotifer (Brachionus rotundiformis). Artemia nauplii, Tigriopus japonicus and artificial diets were significantly higher than that of the larvae fed only either rotifer or artificial diets (P<0.05). The average survival rate and total length of the larvae reared for 50 days after hatching were $22.5\%$ and 62.0$\pm$4.0 mm, respectively. Amount of consumed rotifers at one time feeding by a larva was rapidly increased with growth from 10.3 individuals per larva 5 day old to 65.5 individuals per larva 20 day old.

• Korean Journal of Ichthyology
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• v.27 no.4
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• pp.275-283
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• 2015

Habitat characteristics and feeding ecology of Iksookimia pacifica were investigated in this study to provide baseline data for its ecological characteristics in Bukcheon (stream), Goseong-gun, Gangwon-do, Korea. The main inhabit of I. pacifica was found to be sand bottoms of Bb or Bc river type with slow water flow. Based on studies of their habitat preferences according to age, their preference for sand bed was the same. However, their preference for depth and velocity was different. When their age was increased, their depth preference was also increased ($24.9{\pm}17.61cm$ for 0+ year, $69.6{\pm}30.32cm$ for 1+ year, $82.4{\pm}33.30cm$ for 2+ years, and $90.0{\pm}31.55cm$ for $3+{\leq}$ years). The water velocity was found to be 3.8 ~ 4.0 cm/sec for ages between 0+ and 1+ and 6.0 ~ 7.3 cm/sec for ages between 2+ and $3+{\leq}$. They were active on sand from March to November. They would hibernate in sand during the winter season. During the day from 12 pm to 24 am, they were highly active with high food consumption. Their main food sources analyzed with index of relative importance (IRI) include Chironomidae (76.7%), Simuliidae (10.3%), Rotatoria (7.3%), and Arcellidae (2.2%). Their juveniles (total length 20~40 mm) would feed on small-sized preys such as Rotatoria, Copepoda, and Arcellidae. Older I. pacifica would feed on big-sized preys such as Chironomidae and Simuliidae.

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.62-67
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• 2001

In order to investigate the harmful effects of Fusarium, producing mycotoxins, contaminated cereals, two months feeding study was carried out in SPF-ICR mice. Mice diets were incorporated with 30% Fusarium infected wheat, nepal barley or barley. The wheat was processed to flour. The nepal barley and barley were polished by 68% and 58%, respectively. The cereal incorporating amount in mice diet were 0, 10, 30 and 50% for each processed cereal. Five week-old mice were fed with the prepared diet for 2 months. The effects of Fusarium contaminated cereals on the mice were observed after the feeding. The rates of body weight gain, diet and water consumption were not changed. There were no significant changes on hematology, blood biochemistry, gross and histopathological evaluation, organ weights in all treatment groups. These results suggest that the diets have no deleterious effects to ICR mice.