Sung Hoi Huh

Feeding Habits of the Redbanded Searobin Lepidotrigla guentheri in the Coastal Waters off Gori, Korea

The feeding habits of the redbanded searobin Lepidotrigla guentheri were studied using 186 specimens collected from September to November, 2006, in the coastal waters off Gori, Korea. The sizes of L. guentheri ranged from 7.1 to 16.7 cm total length(TL). L. guentheri is a bottom-feeding carnivore that consumes mainly shrimp, especially Leptochela sydniensis, amphipods, and crabs. Its diet also includes small quantities of stomatopods, mysids, cumaceans, euphausiids, polychaetes, and copepods. Our feeding-strategy graphical method reveled that L. guentheri is a specialized feeder, with a narrow niche width. L. guentheri mainly consumed shrimp of all size classes and did not show significant ontogenetic changes in feeding habits. Smaller individuals(7-11 cm TL) secondly consumed amphipods, with the portion of amphipods in the total diet decreasing as body size increased. Prey size increased signifi cantly as the fi sh grew in size.

Diet composition of juvenile Korean piscivorous chub, Opsariichthys uncirostris amurensis in the surf zone of Nakdong river estuary, Korea

The diet composition of juvenile Korean piscivorous chub, Opsariichthys uncirostris amurensis were studied using 277 specimens collected from January to December 2004 in the surf zone of Nakdong river estuary. The size of Opsariichthys uncirostris amurensis ranged from 2.6 to 9.1 cm in standard length (SL). Opsariichthys uncirostris amurensis was carnivore that consumes mainly amphipods and insects. Its diet also included small quantities of polychaetes, fishes, and algae and plants. Opsariichthys uncirostris amurensis showed ontogenetic diet change. Smaller individuals (

Feeding Habits of Larval Clupea pallasii from the Nakdong River Estuary, Korea

어류는 난에서 자어 및 치어 단계를 거쳐 성어로의 가입이 이 루어지며, 이 시기 동안 매우 높은 사망률을 보인다. 특히 난 황을 가진 전기자어기(pre-larval stage)보다는 외부섭식(exogenous feeding)을 시작하는 시기에 사망률이 매우 높다(Hjort, 1926). 생활사 초기에 적절한 외부섭식이 이루어지지 못하면 기아(starvation)에 의한 직접적인 사망과 낮은 성장률로 인한 부유 자어 기간이 길어지게 되어 다른 포식자에 의해 피식될 확 률의 증가로 이어 질 수 있으며(Shepherd and Cushing, 1980), 결국 이러한 일련의 과정이 어류의 가입량에 영향을 미친다 (May, 1974; Lasker, 1975). 어류 초기생활사에 있어서 먹이의 가용성(prey availability)과 섭식 성공은 생존에 있어서 가장 중 요한 요소이며, 이를 파악하는 것은 동일 연령군(cohort)의 가입 성공 여부와 어류 개체군들의 잠재적 연급군(year class) 강도를 평가하는데 중요한 초석이 된다(Cushing, 1990). 따라서 초기 생활사 단계에서 선호하는 먹이생물을 확인하는 것은 섭식조건 과 먹이요건을 충족하는 자어의 기회를 평가하는데 중요한 요 소이다(Robichaud-LeBlanc et al., 1997). 청어(Clupea pallasii)는 한류성 어류로 우리나라 동해 및 서 해, 일본북부, 발해만, 북태평양 등에 분포하는 부어류이다 (NFRDI, 2004). 청어의 산란기는 겨울에서 봄까지로 긴 산란 기를 보이지만, 주 산란기는 3-4월이며, 해조류 군락이 있는 얕 은 연안이나 내만으로 떼를 이루어 몰려와 해조류와 같은 기질 에 알을 붙이는 산란습성을 보인다(NFRDI, 2004). 청어의 출현량은 주기에 따른 극심한 변동을 보이는데, 우리 나라 청어 자원량의 출현 양상을 시대별로 살펴보면, 1910-20 년대, 1960-70년대에 많은 출현량을 보였으며, 1970년대 이후 부터 출현량이 급격히 감소하였다(Gong et al, 2009). 그러나 2000년대 후반부터 청어의 출현량은 매년 증가하고 있는 추세 이며(KOSIS, 2015), 본 연구해역인 낙동강 하구역과 인근의 진 해만에서도 겨울에서 봄 사이에 청어 자치어의 출현량이 매우 낙동강 하구역에 출현하는 청어(Clupea pallasii) 자치어의 식성 최희찬·박주면·윤석현·허성회*

Feeding habits of Kammal thryssa Thryssa kammalensis (Bleeker, 1849) in the coastal waters of Gadeok-do, Korea

The feeding habits of Thryssa kammalensis was studied using 430 specimens collected from October 2010 to September 2011 in the coastal waters of Gadeok-do, Korea. T. kammalensis in the coastal waters of Gadeok-do was carnivorous predator and planktonic feeder with a wide variety of prey items such as arrowworm, copepods, crab larvae, shrimp larvae, and fish eggs. In addition, T. kammalensis consumed mainly arrowworm, copepods, crab larvae, shrimp larvae, fish eggs, and the diet also included small quantities of cladocerans, amphipods, bivalve larvae, mysids, and euphausiids. On the other hand, the body length (BL) of T. kammalensis specimens ranged from 5.9 to 15.1 cm. Size-related variations in dietary composition of T. kammalensis were not significant that overlap indexes of each major food items that showed very high values in all size classes, representing more than 0.80. Arrowworms were the dominant prey item in all sizes, and copepods were the next most frequent prey item consumed in all size classes. Seasonal changes in dietary composition of T. kammalensis were significant. However, overlap indexes of each major food items in some season showed very high values of 0.80 (between spring and winter) and 0.85 (between summer and autumn). Copepods were most frequently eaten in the spring and winter. Moreover, arrowworm were the dominant prey item in summer and autumn. Mean numbers of prey per stomach (mN/ST) changed significantly with size groups (P < 0.05), but mean wet weight of preys per stomach (mW/ST) showed an opposite tendency (P > 0.05).

Seasonal Variation in the Species Composition of Fish Assemblages in the Coastal Waters off Gadeok-do, South Sea, Korea

Seasonal variations in species composition and abundance of the fish assemblages in the coastal waters off Gadeok-do were determined using monthly sample collection by a small otter trawl in 2010-2011. Of a total of 65 fishes collected, the dominant species were Leiognathus nuchalis, Clupea pallasii, Thryssa kammalensis, Engraulis japonicus, Repomucenus valenciennei, Sillago japonica, Trachurus japonicus, Pennahia argentatus, Okamejei kenojei, Cynoglossus joyneri, Pholis fangi, Pleuronectes yokohamae, and Zoarces gillii. These 13 fishes accounted for 92.8% of the total number of individuals collected. The number of fish species, number of individuals, biomass, and species diversity indices fluctuated with the seasons. The peak number of fishes occurred in April, whereas the biomass of fishes was highest in August. The numbers and biomass of fishes were lower in February corresponding with the low temperatures, and diversity indices were lower in January than in any other month.

Feeding habits of ocellate spot skate, Okamejei kenojei in the coastal waters of Gadoek-do, Korea

The feeding habits of Okamejei kenojei were studied using 242 specimens collected from October 2010 to September 2011 in the coastal waters of Gadeok-do, Korea. O. kenojei was carnivorous feeder that consumed mainly shrimps, crabs, and fishes. Its diet also included small quantities of stomatods, cephalopods, amphipods. The size of O. kenojei ranged from 10.4 to 47.4 cm in total length (TL). O. kenojei showed ontogenetic dietary shift.