• Korean Journal of Ecology and Environment
• /
• v.37 no.1 s.106
• /
• pp.130-136
• /
• 2004

In the present study, prey preference of juvenile fishes was examined using an experimental approach. Zooplankton composition, as a prey of the fish, was evaluated by taking into account the species as well as body size of juveniles in the aquarium. The predation of juvenile fishes is known to be an important factor in changes of zooplankton communities. In some previous studies at the regulated Nakdong River, the collapse of large cladcoerans and an increase in the rotifer population by selective predation during spring and summer were observed. This study focused on the predation of juvenile fishes such as Hyporhamphus sajori, Rhinogobius brunneus, and Opsariichtys uncirostris amurensis on zooplankton community structure in mesocosm scale experiments. These fishes selected the cladoceran Moina micrura with highest individual preference value (Manly/Chesson index)among zooplankton prey in the experimental aquarium. When the size-selective prey preferences of the juvenile fish were compared, both small (body size <2 cm) and large (body size >2cm) juveniles of O. uncirostris positively selected M. micrura. In the outdoor experimental tanks, juvenile fishes consumed the cladoceran M. micrura, resulting in an high abundance of the rotifer, Polyarthra spp. The results suggest that juvenile fish predation may play an important role in regulating the zooplankton community structure by reducing the cladoceran density and increase of rotifers in the Nakdong River during spring and summer.

• The Korean Journal of Ecology
• /
• v.25 no.5
• /
• pp.275-282
• /
• 2002

Preference of food plants of wild birds was shown in the order of Pinus densiflora, Celtis sinensis, Celastrus orbiculatus, Rosa multiflora, Taxus cuspidata, and Euonymus japonica, etc. The wild birds preferred the animal food(92.2%) rather than the vegetable food(32.7%) in breeding season(May through June), but preferred both animal and vegetable foods in non-breeding season(November through December). The rates utilzing artficial nest were 77.5%, 50.3%, 44.1% and 42.2% in Nosan, Sanho, Chinju-castle and Bibong parks, respectively. The wild birds used more the 3cm hole than 5cm hole.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.1
• /
• pp.27-31
• /
• 2001

To investigate the food organisms and feeding selectivity of the white croaker (Argrosomus argentatus) during the postlarval stage, the gut contents of the postlarvae, captured in Kwangyang Bay in 1995, were observed, The food organisms were composed of copepod egg and nauplius, Codonellopsis sp. and Tintinnopsis spp. The indices of relative importance indicated that the most dominant food item was a copepod nauplius. As white croaker larvae grew, the size of prey items and the selectivity for copepod nauplius increased.

• Korean journal of applied entomology
• /
• v.56 no.4
• /
• pp.421-426
• /
• 2017

These experiments were conducted to investigate the morphological characteristics, occurrence ecology, host preference, and oviposition of Locusta migratoria to create a forecasting manual in preparation for outbreaks of this species. The sex ratio (female:male) of 274 adult of L. migratoria which occurred naturally in the Muan region of Jeollanam-do was 18.2 : 81.8, 60.9% individuals were of the green type and 39.1% were of the brown type. Body length and body weight were 6.5 cm and 2.8 g for females and 5.0 cm and 1.5 g for males, respectively; body size did not differ between differently colored individuals. Spawning activity in the field was observed from late August to late October. Eggs laid between late September and early October hatched in late May the following year. Female adults fed 3.5 g of corn leaf and male adult was 1.6 g for a day. The host preference of L. migratoria was in the order corn > foxtail millet > millet > silver grass > rice, and preference for silver grass and rice was very low. Pure sand was most favorable for the spawning of L. migratoria, and the cumulative amount of hatching was higher when the soil moisture content was higher after spawning began.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2000.05a
• /
• pp.294-295
• /
• 2000

양식 어류의 건강 증진을 위한 천연물질 또는 미생물의 개발과 이용에 대한 관심은 점점 높아지는 추세에 있으며, 이것은 양식산업의 친환경적 이미지 부각과 소비자에 대한 양식어의 선호도 증가 등의 장점을 향상시키는데 기여하기 때문이다. 어류의 양식과 관련한 미생물의 이용은 그 중요성에 비해 그다지 많은 연구가 수행 되지 않고 있으며, 어류의 자치어에 대한 먹이생물로서, 또는 어류의 초기먹이생물의 배양 등과 관련한 연구가 중심이 되고 있다(소림, 1966; Okamoto et al., 1988). (중략)

• Korean Journal of Ichthyology
• /
• v.26 no.4
• /
• pp.303-309
• /
• 2014

Feeding ecology of Collichthys lucidus was determined by analysis of stomach contents of 926 specimens ranged from 3.5 to 18.5 cm in the Han River estuary. This fish actively fed on benthic crustaceans, mainly decapods, Palaemon carinicauda and Acetes chinensis, and they can be defined as the benthivorous predator. The percentage of empty stomachs was 23.8%. The vacuity index (VI) did not vary with the size classes, but showed significant monthly variations. Monthly variation of feeding activity appears to be related to the reproduction cycle of the fish, and to the temporal abundance of the prey organisms. Collichthys lucidus in Han River estuary fed on a wide array of prey items and could be considered as a non-selective predator.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.34 no.3
• /
• pp.320-327
• /
• 1998

The feeding habits of jack mackerel, Trachurus japonicus, collected from the Nakdong River estuary from February 1987 to January 1988 were studied. Jack mackerel(4~15cm SL) was a planktivore which fed mainly on copepods, amphipods and mysids. Its diets included small quantities of decapods, euphausiids, polychaetes, chaetognaths and fish larvae. Paracalanus parvus. Acartia clausi and Calanus sinicus were the three most abundant copepod species found in the stomach contents of jack mackerel. Jack mackerel showed ontogenetic changes in feeding habits. Small individuals of the fish(4~7cm SL) preyed heavily on copepods. However, the portion of copepods in stomach contents decreased with increasing fish size, and this decrease was compensated by an increased consumption of amphipods and mysids.

• Korean Journal of Environmental Biology
• /
• v.27 no.4
• /
• pp.334-340
• /
• 2009

In other to know the feeding preference over the degree of ripeness and size of fruits in birds, we gave them to three bird species in breeding condition, counted and analyzed the number of fruits by correspondence ordination technique. Chrysolophus pictus did not show a distinct preference in respect to degree of maturity or size of fruits of among three tree species. Columba rupestris preferred un-ripen fruits over ripen ones of Prunus yedoensis or Elaeagnus multiflora, but did not choose selectively in case of fruits of Malus sieboldii. Pavo muticus showed the reverse favorable pattern of Columba rupestris. Total feeding amounts eaten by birds were dependent on the initial feeding amounts of fruits. These results indicated that in feeding activity some birds chose differently in terms of species or maturity of fruits, but not in fruit size.

• Journal of Wetlands Research
• /
• v.17 no.2
• /
• pp.113-117
• /
• 2015

Even though many researches are conducted for the conservation and restoration of endangered species Menyanthes trifoliata, recently, there is no study on the threatening factors to this plant. This is the first time in Korea to study growth and feeding characteristics of Deilephila elpenor as a threatening factor to Menyanthes trifoliata through an experiment. Experiment was done with 6 Eephant hawk-moth larvae and change of body weight, food preference, and ingestion amount of Bog-bean were investigated. It took 27 days from larva to pupa and maximum body weight of lavae was in the range of 4-7.5g. The food preference sequence of the lavae was Menyanthes trifoliata, Impatiens balsamina, Ampelopsis brevipedunculata var. heterophylla, Parthenocissus tricuspidata. Ingestion model shows the total amount of ingestion by a larva is 11-30g and this amount can be acquired at $0.03-0.08m^2$ of Menyanthes trifoliata pure stand. This study showed Deilephila elpenor as a potential threatening factor and suggests that the conservation and restoration plan of endangered species Menyanthes trifoliata include the control plan of Deilephila elpenor, also.

• Korean Journal of Ichthyology
• /
• v.26 no.2
• /
• pp.118-124
• /
• 2014

As part of researching the feeding habit of Liobagrus somjinensis, the study of its stomach contents and benthic aquatic macroinvertebrates fauna at the waters the fish was collected were carried out monthly from January to December 2010 in Yo stream, Somjin River Sikjeong-dong, Namwon-si, Jeollabuk-do, Korea. In the survey of the stomach contents, the prey organisms are all aquatic insects consisting of 5 orders, 14 classes and 16 species. They fed mainly on Trichoptera and Ephemeroptera including dominant insects such as Hydropsyche kozhantschikovi (79.1%), Chironomidae spp. (48.7%), Baetiella tuberculata (34.2%) at the occurrence rate. Based the result, L. somjinensis appeared to be an aquatic insect feeder that consumes only benthic aquatic insects. The feeding rate of L. somjinensis was the highest in November, whereas it was the lowest in December to next February when they did not feed in the winter season. A survey of the benthic aquatic macroinvertebrates fauna was accompanied for prey preference at the waters. They have 7 orders, 20 classes and 27 species, and among them, two species, Hydropsyche kozhantschikovi (39.0%) and Epeorus pellucidus (18.1%), were aquatic dominant insects. Among 7 orders interestingly, Odonata and Megaloptera, known as having a larger size than other aquatic insects, were not found at the stomach contents. As a result, Liobagrus somjinensis most prefer Hydropsyche kozhantscikovi which is the most dominant species with relatively a smaller size at the waters the study was performed.