Feeding habitis of Pacific cod (Gadus macrocephalus) in the coastal waters off Fadeok-do, Korea

2005년 11월에서 2006년 2월까지 한국 남해 가덕도 주변해역에서 채집한 대구 (G. macrocephalus) 192개체의 위내용물을 분석하였다. 대구의 주 먹이생물은 분홍갯가꼬마새우(E. spathulirostris), 마루자주새우(C. hakodatei), 자주새우(C. affinis) 등과 같은 새우류(Macrura)였으며, 그 다음으로 어류(Pisces)가 많이 섭이 되었다. 그 외 두족류 (Cephalopoda), 단각류(Amphipoda), 게류(Brachyura), 집게류 (Anomura) 등도 대구의 위내용물 중에서 발견되었으나, 그 양은 많지 않았다. 대구의 크기별로 보면 35~45 cm SL 크기군에서는 새우류를 주로 섭이하였으나, 55 cm 이상의 큰 개체는 새우류와 어류와 두족류를 골고루 섭이하였다. 본 연구에서 대구의 먹이생물 중 잘피밭에 서식하는 실고기가 많이 발견되었는데 이는 대구가 가덕도 주변해역에 분포되어 있는 잘피밭에서 상당 시간을 머물고 있음을 의미한다. 이 결과로 미루어보아 대구가 진해만을 포함한 가덕도 주변해역으로 산란하러 오는 것은 부화된 자어와 치어가 어린 시기를 먹이가 풍부하고 보다 안전한 잘피밭에 머물며 성장하도록 하기 위한 생존전략으로 추정된다. The feeding habits of Pacific cod (Gadus macrocephalus) were studied based on the examination of stomach contents of 192 specimens collected from November, 2005 to January, 2006 in the coastal waters off Gadeok-do, Korea. The size of Pacific cod ranged from 35 to 82 cm in standard length (SL). Pacific cod mainly consumed shrimps such as Eualus spathulirostris, Crogon hakodatei and C. affinis and fishes. Its diet also included small quantities of cephalopods, amphipods, hermit crabs and crabs. Individuals between 35 cm and 45 cm SL mainly consumed shrimps. The portion of shrimps decreased with increasing fish size, and this decrease was paralleled with increased consumption of fishes and cephalopods. In this study we found Syngnathus schlegeli in the stomach contents of many Pacific cod specimens. S. schlegeli is a typical seagrass fish species which inhabits in seagrass beds, This fact means that Pacific cods stay in the seagrass beds during spawning period. Therefore migration of Pacific cod to coastal waters off Gadeok-do during spawning period seems to be a survival strategy for its larvae and small juveniles to stay in seagrass beds which provide with abundant foods and shelters to many commercial fish species.N

Feeding Habits of 6 Shark Species in the Southern Sea of Korea

The feeding habits of six shark species, Scyliorhinus torazame, Mustelus manazo, Squalus megalops, Isurus oxyrinchus, Alopias pelagicus, and Carcharhinus plumbeus were studied using the stomach contents of 463 specimens collected between January and February 2007 in the southern sea of Korea. They consumed different prey items. S. torazame preyed mainly crustaceans, and M. manazo on crustaceans and fishes. S. megalops, I. oxyrinchus, A. pelagicus, and C. plumbeus consumed predominately fishes. Non-metric multi-dimensional scaling (NMDS) ordination plots emphasized that dietary similarities separated thesix shark species into three trophic groups based on similarities in percentage Index of Relative Importance (%IRI): Group I (crustacean feeders), Group II (fish and crustacean feeders), and Group III (fish feeders).N

Seasonal Variation in Species Composition and Abundance of Fish Assemblages Collected by a Threesided Fyke Net in the Coastal Waters off Gori, Korea

2006년 1월에서 12월까지 매월 삼각망에 의해 채집된 어류의 종조성의 계절변동을 분석하였다. 조사기간 동안 35과에 속하는 59종의 어류가 채집되었다. 우점종은 대부분 부어류로 전갱이 (Trachurus japonicus), 숭어 (Mugil cephalus),전어(Konosirus punctatus), 열동가리돔(Apogon lineatus),성대(Chelidonichthys spinosus), 망상어(Ditrema temmincki),조피볼락(Sebastes schlegeli) 그리고 줄도화돔(Apogon semilineatus)이었는데, 이들 8종은 전체 채집 개체수의 92.7%를 차지하였다. 본 조사해역의 채집된 어류는 뚜렷한 계절변동을 보였는데 개체수는 12월, 생체량은 3월에 가장 높은값을 보였고, 수온이 낮은 겨울철에 개체수와 생체량이 모두 낮은 값을 보였다. 종다양도지수는 12월에 다른 계절에비해 가장 낮은 값을 나타내었다. Seasonal variation in species composition and abundance of fish assemblage in the coastal waters off Gori were determined using monthly samples collected by a three-side fyke net in 2006. Of a total of 59 fishes collected, the dominant species were Trachurus japonicus, Mugil cephaIus, Konosirus punctatus, Apogon lineatus, Chelidonichthys spinosus, Ditrema temmincki, Sebastes schlegeli and Apogon semilineatus. These 8 fishes accounted for 92.7% 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 December, whereas biomass of fishes was the highest in March. The number and biomass of fishes were lower in January corresponded with the low temperatures, and the diversity indices were lower in December than in any other month.N

Reproductive Ecology of a Goldeye rockfish, Sebastes thompsoni (Scorpaeniformes: Scorpaenidae) in the Coastal Waters of Busan, Korea

부산 주변해역에서 2005년 1월부터 12월까지 매월 채집된 불볼락 421개체의 생식생태를 조사하였다. 불볼락의 체장범위는 13.8~31.8 cm SL이었다. 불볼락 암컷의 생식소중량지수는 3월에 가장 높았으며 그 이후 6월까지 감소하였다. 수컷의 경우 생식소중량지수는 2월에 가장 높았으며 그 이후 감소하였다. 산란시기는 1~6월로 추정되었다. 불볼락의암수간 성비에서는 유의한 차이가 나타나지 않았다(χ2-test,p¤0.05). 불볼락 암컷의 최소성숙체장은 16.8 cm였고 50%성숙체장은 20.11cm로 추정되었다. 모든 암컷은 25 cm 이상의 성숙하였고 난경은 0.6~1.75mm의 범위를 보였다. 포란수는 23,881~44,509개의 범위였고, 평균 30,937개 였다. 체장과 포란수의 관계식은 F=9.3762 SL1.1662(R2=0.8120), 체중과 포란수의 관계식은 F=184.37 Ln(BW)-665.09(R2=0.8713)로 추정되었다. The reproductive ecology of the goldeye rockfish (Sebastes thompsoni) was examined using 421 specimens collected monthly from January to December 2005 in the coastal waters of Busan, Korea. Specimens ranged in standard length (SL) from 13.8 to 31.8 cm. The gonadosomatic index (GSI) of females was highest in March and decreased until June. In males the GSI was the highest in February after that the values declined. The spawning season lasted from January to June, and the ratio of female to male did not differ significantly (x2-test, p>0.05). The length at first spawning was 16.8cm SL, and the size at 50% maturity was estimated at 20.11 cm SL. All females more than 25 cm SL were sexually mature and the egg diameters were from 0.60 to 1.75 mm. Fecundity (F) ranged from 23,881 to 44,509 eggs, with a mean of 30,937 eggs. The relationship between fecundity and standard length was estimated as F=9.3762 SL1.1662 (R2=0.81). The relationship between fecundity and body weight (BW) was estimated as F=184.37 Ln (BW) - 665.09 (R2=0.87).N

Feeding Habits of Scorpaena neglecta in the Coastal Waters off Busan

2006년 1월에서 12월까지 부산주변해역에서 출현하는 살살치 478개체의 식성을 조사하였다. 살살치의 표준체장은 9.0~23.5 cm의 범위를 보였다. 살살치의 주요 먹이생물은 반딧불게르치, 줄비늘치, 도화망둑 등과 같은 어류였으며, 그 다음으로 새우류, 게류가 중요한 먹이생물이었다. 그외 두족류, 갯가재류 등도 위내용물에서 발견되었으나 그양은 많지 않았다. 표준체장 16 cm 이하의 살살치는 게류와 새우류를 주로 섭식하였으며, 16 cm 이상에서는 어류를 주로 섭식하였다. 살살치의 먹이생물크기를 살살치의 체장이 증가함에 따라 증가하는 경향을 보였다. The feeding habits of Scorpaena neglecta were studied based on an examination ofthe stomach contents of 478 specimens collected between January and December 2006 in theCoastal Waters off Busan. The specimens ranged from 9.0 to 23.5cm in Standard length(SL). S. neglec-ta is a piscivore and consumes mainly teleosts such as Acropoma japonicum , Coelorinchus multispi-nulosus , Chaeturichthys stigmatias. Its diet also includes crabs, shrimps, cephalopod and stoma-topod. Smaller individuals (16 cm SL) consume mainly crabs and shrimps. The proportion of theseprey items (crabs and shrimps) decreases with increasing fish size, and this decrease parallels theincreased consumption of fish. The mean prey size sharply increases between 12 and 20 cm SL of S.neglecta size.N

Feeding Habits of Lateolabrax japonicus in the Coastal Waters off Dolsan-do, Yeosu

여수 돌산도 주변해역에서 출현하는 농어의 주먹이생물 과 성장에 따른 먹이생물 변화양상을 연구하기 위하여 2005년 1월에서 12월까지 매월 낚시, 자망, 정치망 등에 의 해 어획된 시료를 여수어시장에서 구입하였다. 총 344개체 의 농어 시료를 분석하였으며, 이들의 체장은 표준체장 8.7~52.8 cm의 범위를 보였다. 농어의 위내용물을 분석한 결과 농어의 가장 중요한 먹이생물은 어류로 나타났다. 어 류 중에서는 멸치, 전갱이, 문절망둑 등을 많이 섭식하였다. 어류 다음으로 중요한 먹이생물은 새우류로 나타났으며, 그 외 단각류, 두족류, 갯지렁이류, 곤쟁이류, 게류 등도 섭식하 였으나 그 양은 많지 않았다. 농어는 체장 25 cm 이하의 비 교적 작은 체장에서는 단각류와 새우류를 주로 섭식하였 다. 그러나 성장함에 따라 이들 먹이생물의 비율은 줄어들 어 체장 25 cm 이상에서는 어류를 주로 섭식하였다. The feeding habits of Lateolabrax japonicus were studied based on an examination of the stomach contents of 344 specimens collected monthly from January to December, 2005 in coastal waters off Dolsan-do, Yeosu. The standard length (SL) of specimens ranged in 8.7~52.8 cm. L. japonicus is a piscivore that consumes mainly teleosts such as Engraulis japonicus, Trachurus japonicus, and Acanthogobius flavimanus. Its diet also includes Macrura, Amphipoda, Cephalopoda, Polychaeta, Mysidacea, and Branchyura. Small individuals (<25 cm SL) consume mainly Amphipoda and Macrura. The proportion of these prey items decreases with increasing fish size, and this decrease paralleled the increased fish consumption.N

Infectious of Proteus vulgaris in Black-spotted porcupine fish

The genus Proteus has been rarely isolated from cultured fish. In this study, we reported Proteus vulgaris isolated from fish skin lesion of Black-spotted porcupine fish (Diodon hystrix). Identification of P. vulgaris was performed by general biological test, including API 20E and API ZYM. The sensitivity of isolated strains to different groups of antibiotics was evaluated using the disc diffusion method. It showed that the isolate is sensitive to ciprofloxacin (5 μg), norfloxacin (10 μg), enrofloxacin (5 μg), cefotaxime (30 μg).N

Maturation and Spawning of Shuttles Hoppfish Periophthalmus modestus in the Mud Flat of Suncheon Bay, Korea

The maturation and spawning of Shuttles hoppfish Periophthalmus modestus were studied from April to October, 2005 in the mud flat of Suncheon Bay, Korea. The specimens ranged in body length (BL) from 1.5 to 8.4 cm. The gonadosomatic index (GSI) of females was highest in May and decreased until September. The hepatosomatic index (HSI) and fatness index of females were high in April and then decreased to a nadir in July. The data indicate that the spawning season was from April to September. There was no significant difference in the ratio of females to males (X2−test,p>0.01). Over 50% of the females over 5 cm in BL were sexually mature. Fecundity ranged from 1,664 to 13,428. The relationship between fecundity (F) and body length (BL) of the fish was expressed as F=0.026BL2.8638(R2=0.79). The first spawning length was 4.5 cm BL.N

Reproduction of the Goby Fish Periophthalmus magnuspinnatus in Mud Flat of Suncheon Bay, Korea

Reproduction of the goby fish Periophthalmus magnuspinnatus was examined using 298 specimens collected from April to October 2005 in a mud flat of Suncheon Bay, Korea. Specimens ranged in body length (BL) from 1.3 to 9.1 cm. The gonadosomatic index (GSI) of females was highest in June and decreased until August. The hepatosomatic index (HSI) and fatness index of females were high in April and then decreased to nadirs in July. Spawning season lated from April to August and the ratio of females to males did not significantly differ (χ2-test, p>0.05). The first spawning length was 4.5cm BL, and the size of 50% maturity was estimated at 4.98cm BL. Fecundity (F) ranged from 1,316 to 4,768 eggs, and the relationship between F and BL was estimated as F＝0.1562BL1.4068 (R2＝0.59).N