Sang Chul Yoon

Variations in species composition of demersal organisms caught by trawl survey in the East Sea

To examine species composition, abundance and biomass of demersal organisms in the East Sea, bottom trawlsurvey was conducted at 7 sea areas from 2005 to 2007. A total of 107 species were collected and werecomposed of 54 fish species, 16 crustacea, and 37 mollusks in the East Sea from 2005 to 2007. Yearlyabundance per area which caught by trawl survey in the East Sea from 2005 to 2007 ranged from a high of292,234inds./km

Age and growth of the sandfish, Arctoscopus japonicus in the East Sea of Korea

were investigated from samples of the eastern seadanish seine and gill net fishery in the East Sea of Korea from February, 2004 to December, 2007. Ages weredetermined from annuli in otoliths and annuli were formed between December and February once a year.Also, the main spawning period was estimated to be between December and January, thus rings wereconsidered to be annual marks. For the relationship between fork length and total weight, a multiplicativeerror structure was assumed because variability in growth increased as a function of the length. Therelationship between fork length and total weight were TW0.0083FL

Development of artificial spawning seaweeds of the sandfish, Arctoscopus japonicus

began to attach the egg massto artificial spawning seaweeds when sea temperature dropped below 10in December, spawned heavilywhen it was around 8in January, and completed the behavior when it started to increase over 10inFebruary. The hatching period of eggs was estimated to be about 60 days. The middle position in artificialspawning seaweed had the highest number of egg masses and the diameter of the egg mass ranged from 25mmto 62mm. Based on the result for the effects, the artificial spawning seaweeds of

Age and Growth of Blackfin Flounder Glyptocephalus stelleri in the East Sea, Korea

Age and growth of Glyptocephalus stelleri in the East Sea of Korea were determined, from monthly samples of commercial catches, caught by the eastern sea Danish seine fishery in 2007. The annuli of G. stelleri are formed once a year, with the boundary between opaque and translucent zones forming in September. Relationships between total length (TL) and total weight (TW) were TW=0.002TL 3.392 (r 2 =0.970) for females and TW=0.002TL 3.335 (r 2 =0.961) for males. TLs at annuli formation in otoliths were backcalculated from the otolith-length relationship and were adjusted to von Bertalanffy growth curves to Lt=39.71(1 – exp (-0.152(t+1.156)) ) for females and Lt=32.16(1 – exp (-0.213(t+0.879)) ) for males. From the age of 3 yerars, females grew faster than males (P<0.05).

Community Structure and Distribution Pattern of the Pleuronectiform Fishes in the Uljin Marine Ranching Area, Korea

To elucidate the variation of species composition, biomass and length distribution of flatfishes by the period and region in the Uljin marine ranching area, bottom trawl survey was investigated at the six stations from Feb. 2008 to Dec. 2010. During the survey period, a total 4 families 17 species in the Pleuronectiformes, average 69,158 and 5,625 were identified, in 2008 appeared in 14 species, average 25,798 and 2,333 and in 2009 appeared in 13 species, average 102,360 and 5,634 and in 2010 appeared in 14 species, average 75,704 and 8,632 . The individual dominant species, occupying over 10% of total individuals, was Pleuronectes herzensteini (20,811 ind., 30.0%), Hippoglossoides pinetorum (18,666 ind., 26.9%) and Glyptocephalus stelleri (13,499 ind., 19.4%) also the biomass dominant species, occuping over 10% of total biomass, was P. herzensteini (2,207 kg, 39.3%), Pleuronectes yokohamae (857 kg, 15.3%), H. pinetorum (761 kg, 13.5%), Kareius bicoloratus (677 kg, 12.1%). From the cluster and MDS analysis based on Bray-Curtis similarity matrix of fourth root transformed data of species number and individuals in the Uljin marine ranching area from Feb. 2008 to Dec. 2010 was divided into two different groups of the flatfishes community in 2008 and from Jan. to Apr. in 2009 and 2010 (Group A) and the pleuronectiform community in from May to Dec. in 2009 and 2010 (Group B). From the cluster and MDS analysis using the similarity of demersal organisms community among six stations, the Uljin marine ranching area was divided into two different groups of Group 1 (St. 1 and St. 3) and Group 2 (St. 2, St. 4, St. 5 and St. 6).

Feeding Habits of the Pacific Cod Gadus macrocephalus in the Coastal Waters off Jumunjin, Gangwondo of Korea

The feeding habits of the Pacific cod Gadus macrocephalus were studied by analyzing the stomach contents of 423 specimens caught by coastal gill net in the coastal waters off Jumunjin, Gangwondo, Korea, from January to December, 2011. The size of Pacific cod ranged from 31.0 to 86.5cm in total length (TL). The proportion of empty stomachs was 25.1%. The main prey items were Macrura, Pisces, and Cephalopoda. In order of abundance, the most dominant species of Macrura, were Pandalus eous, Argis lar, and Neocrangon communis, and the most dominant species of Pisces, were Clupea pallasii, Actoscopus japonicus, and Glyptocephalus stelleri. Berryteuthis magister was the most dominant species of Cephalopoda. In terms of variation in feeding habits by growth, Macrura was the most important prey group for G. macrocephalus ranging in TL from 30- to 55 cm, but Pisces was the most important prey group for cod over 56 cm TL. Catch of G. macrocephalus was significantly positively correlated to catch of the three major Pisces prey species Clupea pallasii, Actoscopus japonicus and Glyptocephalus stelleri.

Community Structure of Fisheries Resources Caught by Dredge in the Uljin Marine Ranching Area, Korea

근해어업의 발달과 연안오염의 가중, 양식어업의 증가 등으 로 연안어장의 생산성이 저하되면서, 우리나라의 연근해 어업 의 총어획량은 1980년대 이후 감소하고 있는 실정이다(Fujita, 1987; Yotsui and Maesako, 1993; MIFFAF, 2008). 이러한 수 산자원 감소를 방지하기 위한 여러 방안 중에 바다목장 사업 은 수산자원의 방류에서 어획에 이르기까지 자연친화적으로 관리하는 어업생산시스템으로 인공어초, 해조장 등 인위적인 시설물의 설치를 통해 어패류 자원의 서식공간을 제공하고 수 산종묘 방류를 통해 고갈되어 가는 수산자원을 증대시켜 안정 적인 수산물 생산 및 공급을 목적으로 한다(MOMAF, 2005; MIFFAF, 2008; Lee et al., 2012). 또한, 바다목장 사업은 어장 을 적극적으로 선택하고 조성하는 과정에서 생물자원의 현존량 변화 및 생태특성에 관한 자료를 축척함으로써 효율적인 생태 계 관리모델을 개발하는데도 그 목적이 있다. 울진바다목장에서는 어류 및 패류의 자원량을 증대시킬 목적 으로 조피볼락(Sebastes schlegelii), 쥐노래미(Hexagrammos otakii)와 같이 암반 주변에 정착하여 서식하는 어류와 강도다 리(Platichthys stellatus), 넙치(Paralichthys olivaceus)와 같은 울진바다목장에서 형망으로 어획된 수산자원의 군집구조

Seasonal Variations in the Species Composition of Fisheries Resources Caught by Trammel Net in the Uljin Marine Ranching Area, East Sea

Variations in the species composition, biomass and size distribution of fisheries resources in the Uljin marine ranching area were investigated using trammel nets at two stations (artificial reef and natural rocky area) from 2009 to 2010. During the survey, a total of 74 species were sampled with a mean density of 132 ind./net and mean biomass of 21.56 kg/net. In the natural rocky area, a total of 45 species were sampled at a mean density of 202 ind./net and mean biomass of 28.81 kg/net, while in the artificial reef area, samples included a total of 56 species, with means of 62 ind./net and 14.30 kg/net. The dominant species, comprising over 3% of the total number of individuals, were Suberites ficus (30.8%), Ovalipes punctatus (19.2%), Paralichthys olivaceus (11.7%), Pleuronectes herzensteini (4.7%), Kareius bicoloratus (3.5%), Pseudopleuronectes yokohamae (3.5%) and Eopsetta grigorjewi (3.0%). The dominant species, in terms of biomass, comprising over 5% of the total biomass, were P. olivaceus (22.1%), S. ficus (18.7%), O. punctatus (7.2%), Hexagrammos otakii (6.6%), P. yokohamae (5.7%), K. bicoloratus and P. herzensteini (5.3%). A cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on the Bray-Curtis similarity of fourth root transformed data for number of species and individuals, was divided into two groups: the artificial reef area (group A) and the natural rocky area (group B).

Reproduction and distribution of Chionoecetes crabs (C. opilio and C. japonicus) in the East Sea

Reproduction and distribution of Chionoecetes crabs (C. opilio and C. japonicus) in the East Sea Hyung Kee Cha, Jae Hyeong Yang*, Sung Il Lee1 and Sang Chul Yoon1 Dokdo Fisheries Research Center, East Sea Fisheries Research Institute, National Fisheries Research and Development Institute, Pohang 791-110, Korea 1Fisheries Resources Management Division, National Fisheries Research and Development Institute, Busan 619-705, Korea

Feeding Habits of the Black-edged Sculpin Gymnocanthus herzensteini in the Coastal Waters off Mukho, Gangwondo of Korea

The feeding habits of the black-edged sculpin Gymnocanthus herzensteini were studied using 944 specimens collected from February 2011 to January 2012 in the coastal waters off Mukho, Gangwondo, Korea. The G. herzensteini ranged from 11.8 to 36.3 cm in total length (TL). The percentage of empty stomachs in G. herzensteini was 40.2%, and the main prey items were Pisces, Euphausiasea, and Macrura. The smallest size group (11.8-15.0 cm TL) consumed mainly Polychaeta and Amphipoda. The quantity of prey increased in proportion to sculpin size. The composition of prey items and feeding habits of G. herzensteini exhibited seasonal fluctuations, that is, the main prey items during spring were Euphausiasea, whereas those during other seasons were Pisces.