이 연구는 제주연안 해역에서 갯녹음의 확산동향과 기후변화로 인한 동계 수온변화(수온상승)가 갯녹음 확산에 미치는 영향을 알아보고 갯녹음 원인생물인 무절석회조류의 번식과 생장을 파악하기 위해 연구되었다. 제주연안의 갯녹음 발생면적은 1998년에는 2,931ha였으나, 2003년에는 4,541ha로 증가하였다. 발생해역도 1998년은 제주도 남부 해역에서 주로 발생했으나, 2003년에는 조천읍, 구좌읍을 제외한 제주도 전역으로 확산되었다. 1992년부터 2004년까지 관측된 2월 평균수온은 갯녹음 해역 15.1℃, 해중림 해역 13.9℃로 갯녹음 해역이 1.2℃가 높게 나타나 두 해역 간 뚜렷한 차이를 보였으나, 8월 수온은 두 해역 간 차이가 없었다. 수온의 장기변동(37년)에서도 갯녹음 해역이 평균 15.3℃인데 비하여 해중림 해역은 평균 14.1℃로 갯녹음 해역이 해중림 해역보다 1.2℃가 높게 나타났다. 연간 수온 증가 값은 갯녹음 해역이 매년 0.038℃씩 증가하고 있는 반면, 해중림 해역은 0.024℃씩 증가하여 장기 수온변동은 갯녹음 해역이 해중림 해역보다 높았다. 이와 같이 기후변화로 인한 지속적인 동계 수온상승은 제주도 갯녹음을 확대시 키고 있음을 시사하고 있다.

제주 연안 저서생물(해조류, 무척추동물)의 군집구조가 저서 기질 형태에 따른 차이를 파악하기 위해 신흥해역에서 2015년 2월부터 11월까지 매월 조사되었다. 암반정점에서는 해조류 57종과 무척추동물 102종이 출현하였고, 몽돌정점 에서는 해조류 42종과 무척추동물 67종이 관찰되어 암반기질에서 저서생물의 출현종수가 높은 것으로 나타났다. 해조 류의 연평균 생물량은 암반정점에서 1,601.13 g wet wt./㎡으로 몽돌정점의 448.85 g wet wt./㎡보다 약 4배 높았다. 감태는 암반정점에서 전체 생물량의 62.64% (1,002.93 g/㎡)를 차지하는 우점종이었고, 몽돌정점에서는 넓은게발, 감태, 붉은뼈까막살, 자루바다표고, 갈래곰보가 우점하였다. 저서무척추동물의 개체수 및 생물량은 암반정점에서 각각 106.9 indivi./㎡, 871.93 g/㎡이며, 몽돌정점에서는 64.6 indivi./㎡, 984.28 g/㎡로 나타났다. 무척추동물의 생물량 우점종을 파악한 결과, 암반정점에서는 소라(36.40%), 바퀴고둥(19.18%), 보라성게(13.61%)였고, 몽돌정점에서는 거 품돌산호(54.13%)와 그물코돌산호(24.28%)로 기질에 따른 우점종의 차이를 확인하였다.

The survey was conducted to investigate biomass and distribution of fisheries resources using a quantitative echo sounder and a fixed gillnet around Marado coast of Jeju to obtain the scientific basic data for dispute resolution with a large purse seine fishery and coastal fishing and policy establishment of reasonable fisheries resources. Hydroacoustic surveys were conducted six times (November 28~29, 2015 (night), February 23~24, 2016 (night) and March 3~4, 2016 (night/day), March 30~31, 2016 (night/day)) using a quantitative echo sounder. The pelagic fish densities were relatively higher around Marado in November 2015, February 2016 and March 3~4, 2016. However, demersal fish densities were relatively higher in Jeju coastal waters on March 30~31, 2016. Catch data using fixed gill net were used to calculate biomass. Based on the hydroacoustic data, fish length-weight function and target strength information of dominant fish, the biomass of fishes were estimated as follow: 5.64 ton CV = 70.2% at night on November 28-29 2015, 7.14 ton CV = 35.8% of pelagic fish and 530.77 ton CV = 34.6% of demersal fishes at night on February 23-24 2016, 2.34 ton CV = 56.7% of pelagic fish and 571.93 ton CV = 40.3% of demersal fish at daytime, 1.39 ton CV = 48.4% of pelagic fish and 194.59 ton CV = 54.3% of demersal fish at night on March 3~4 2016, 0.37 ton CV = 72.9% of pelagic fish and 338.79 ton CV = 99.7% of demersal fish at daytime, 0.24 ton CV = 21.3% of pelagic fish and 68.61 ton CV = 53.8% of demersal fish at night on March 30~31 2016.

Seagrasses, sea flowering plants, comprise approximately 60 species globally and are often called ‘ecosystem engineers’ because they create their own habitats by modifying the surrounding environments, which provide coastal zones with a number of crucial ecosystem services. Zostera marina (the common name ‘eelgrass’) is one of the seagrass beds-forming species distributed widely in northern hemisphere including the Korean coast, which plays a pivotal role in ecosystem as a primary producer and a nursery habitat or refuge for other marine organisms. However, due to global climate change and anthropogenic activities such as reclamation and dredging, there has recently been a drastic decline in population sizes of Z. marina in Korea. In order to develop effective conservation and restoration management programs of Z. marina populations, it would be helpful to consider all biological aspects of this species such as genetic characteristics as well as ecological and physiological features. This study first provides information on genetic diversity and genetic structure of Jeju Island and Namhae populations of Z. marina, which will contribute to the establishment of appropriate conservation and restoration management plans for future persistence of this species. Using six microsatellite markers, we investigated the level of genetic diversity and genetic structure among 10 geographic populations of Z. marina inhabiting Jeju Island (Hamdeok, Tokki-seom, Sungsan, Woljeong, Ojo) and Namhae (Gamak bay, Jindong bay, Nampo, Anggang bay, Geoje) on the southern coast of Korea. The level of genetic diversity within Jeju populations (mean allelic richness [AR]: 1.57 ~ 3.09) was found to be significantly lower than Namhae populations (AR: 3.09 ~ 4.29) (Mann-Whitney U-test, P < 0.05). These findings suggest that effective population sizes (Ne) of Jeju populations are generally smaller than those of Namehae populations. Within Jeju Island, Hamdeok population had the smallest population size (coverage: 138 m2) and the lowest genetic diversity (AR: 1.57), while Ojo population had the largest population size (coverage: 275,736 m2) and the greatest level of genetic diversity (AR: 3.09). Hamdeok population showed evidence of genetic bottleneck. These results again suggest that Ne of Jeju populations is generally low (except Ojo population). Among Jeju populations, all pair-wise comparisons of FST values (i.e., degree of genetic differentiation) were highly significant (FST = 0.0612 ~ 0.7168, P < 0.001) despite Jeju populations that were geographically closely located, indicating that these local populations are genetically divergent, probably due to a lack of gene flow among the populations. The observed strong population structure was substantiated by evidence that five genetic clusters are most likely, based on population assignment test (STRUCTURE). The Mantel test showed a positive relationship between genetic distance (FST) and geographic distance (km) across all the populations sampled (R2 = 0.4118, P < 0.05), suggesting that our data follow Isolation By Distance (IBD) model. Woljeong population revealed the highest level of FST values compared to other populations within Jeju Island in IBD. STRUCTURE and factorial correspondence analysis (FCA) further showed that some Woljeong individuals included genotypes of Namhae populations. Population size of Woljeong (coverage: 310m2) was approximately 50 % smaller than that of Sungsan (coverage: 841m2); however, extent of its genetic diversity (AR: 2.39) was even higher than that of Sungsan population (AR: 1.77). We speculated that Woljeong population underwent a transplantation from Namhae populations with relatively higher level of genetic diversity. FST values within Namhae populations were relatively lower (compared to within Jeju Island) despite the populations that were geographically more distant. It means that level of gene flow is higher among Namhae populations than among Jeju populations. Z. marina is known to have different life histories by water depth. In subtidal zone (deep water depth) populations predominantly undertake sexual reproduction through seeds such as annual life history, whereas those of intertidal zone (shallow water depth) undertake both sexual and asexual reproductions through horizontal rhizomes i.e., perennial life history. STRUCTURE analysis showed no clear differences between shallow and deep populations at Namhae, but some FST values were statistically significantly different despite their low values. For Geoje population sampled in 2005, intertidal and subtidal populations were not significantly different (FST = 0.0045, P = 0.033), but these populations sampled in 2015 showed a significant difference (FST = 0.0328, P < 0.001). It means that genetic structure of Geoje has been changed over the 10 year period between shallow and deep populations. Overall, the Jeju and Namehae populations analyzed in the current study have relatively low levels of genetic diversity and distinct genetic compositions, which warns the message that this ecologically important species should be conserved separately in the local populations and with high priority. We propose that future conservation and restoration plans for seagrasses should consider genetic characteristics particularly because a close relationship between genetic diversity and ecological performance in marine species has been well documented.

Marine macroalgal community structure of subtidal zones were examined at eight study sites, Jeju, Korea, from March to June 2010. A total of 182 species were identified, including 22 green, 37 brown and 123 red algae. Of them, 15 species were observed at all the study sites. Species richness of seaweeds was maximal at Seongsan with 112 species and minimal at Sinheung with 44 species. Average seaweed biomass was 735.24 g wet wt. m-2 and ranged from 165.82 g wet wt. m-2 at Sinheung to 1,160.43 g wet wt. m-2 at Bomok. Articulated coralline algae were dominant occupying 27.05% (198.92 g wet wt. m-2) of total biomass for the eight study sites in Jeju Island. Subdominant species were Ecklonia cava and Codium coactum, comprising 26.62% (195.72 g wet wt. m-2) and 8.42% (61.91 g wet wt. m-2), respectively. Vertical distribution of subtidal seaweeds in terms of biomass showed from E. cava Colpomenia sinuosa - Codium coactum Ecklonia kurome Undaria pinnatifida - Cladophora wrightiana - Peyssonnelia capensis in the subtital zone between 5~15 m depth level.

Fish was caught by a set net in Gwideok, Jeju island that was studied to determine monthly variation of species composition and catch from May 2005 to October 2006. Total catch was 54 species, 44,118 individuals, and 2,152,423.7 g during survey period. Dominant species were Trachurus japonicus and Siganus fuscescens that held 91.3% of total individuals and 71.3% of total abundance. The highest individuals and abundance of catch were in July 2005, and the lowest individuals and abundance of catch were in October 2006 and in October 2005, respectively. As the result, temporal change in abundance have corresponded with changing water temperature.

The age and growth of rabbit fish, Siganus fuscescens were investigated from samples monthly collected in the coast of Jeju island, Korea from February to December 2012. Ages were determined from annuli in otoliths, and annuli were formed in one or two months immediately after spawning once a year. Also, main spawning period was estimated between July and August, thus rings were considered as annual marks. The von Bertalanffy growth equations estimated from a non-linear regression method were Lt=37.24 (1－e－0.33(t + 1.24)) (R2=0.92) for female and Lt=31.44(1－e－0.45(t + 1.23)) (R2=0.90) for male, and the growth between female and male was different.

제주연안선 부근에 밀집된 육상양식장 배출구 주변 4개 해역(애월리, 행원리, 표선리, 일과리)에서 수질환경의 시공간적 변화에 영향을 미치는 요인을 파악하기 위해 2010년 2월부터 2011년 12월까지 격월로 총 12회 조사하였다. 주성분 분석 결과 조사해역에서 연중 영양염의 분포는 염분과의 관련성 없이 배출구로부터 공급되는 물질에 의해 영양염의 농도가 조절되어, 연안에서 외해역으로 갈수록 농도구배가 감소하는 특징을 나타냈다. 특히 용존무기질소의 경우는 배출구와 인접한 해역에서는 부영양상태로 인에 비해 질소가 과잉되고 있었다. 유기물의 분포는 담수유입량이 증가하는 고수온기에 증가하는 경향을 보였다. 식물플랑크톤의 생물량 변화는 애월 및 행원해역은 담수유입과 관련된 기상요인(기온 및 강우), 표선 및 일과는 영양염의 인위적 공급요인(양식장 배출수)에 의한 영향을 주로 받는 것으로 나타났다. 특히, 배출구로부터 직선거리 약 300 m 및 수심 10 m이내 해역의 표ㆍ저층에서는 고영양염 농도 분포가 지속되고 있어, 부영양화 과정에서 발생하는 문제를 직ㆍ간접적으로 받을 수 있는 가능성을 나타냈다. 육상양식장의 운영 시 취수지점이 배출수의 영향을 받는 지점에 위치할 경우 사육수질의 문제가 발생할 수 있다.

In order to obtain the fundamental data about the behavior of conger by underwater audible sound, this experiment was carried out to investigate the hearing ability of Conger eel Conger myriaster which was in the coast of Jeju Island by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of conger eel extended from 50Hz to 300Hz with a peak sensitivity at 80Hz including less sensitivity over 200Hz. The mean auditory thresholds of conger eel at the frequencies of 50Hz, 80Hz, 100Hz, 200Hz and 300Hz were 105dB, 92dB, 96dB, 128dB and 140dB, respectively. The positive response of conger eel was not evident after the sound projection of over 200Hz. At the results, the sensitive frequency range of conger eel is narrow in spite of swim bladder. Auditory masking was determined for Conger eel by using masking stimuli with the spectrum level range of about 60~70dB (0dB re 1μPa/Hz). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise including critical ratio at 68dB of white noise from minimum 26dB to maximum 30dB at test frequencies of 80Hz and 100Hz. The noise spectrum level at the start of masking was distributed at the range of about 68dB within 80~100Hz.

The feeding habits of Sebastiscus marmoratus collected from the Western Coastal Waters of Jeju Island between June 2008 and July 2009 were studied based on examination of the stomach contents. A total 254 individuals of S. marmoratus ranged from 13.2 to 29.6cm (mean 20.7cm) in Standard length (SL). S. marmoratus consumed mainly teleosts such as Chromis notata and Sebastes inermis. Its diet also includes shrimps and crabs. The individuals smaller than 15cm SL consumed mainly shrimps, but on the other hand the individuals larger than 25cm SL consumed mainly fishes. The proportion of fish consumption increased with increasing size of S. marmoratus.

In order to obtain the fundamental data about the behavior of sharks by underwater audible sound, this experiment was carried out to investigate the auditory characteristics of tiger shark Scyliorhinus torazame which was caught in the coast of Jeju Island by heart rate conditioning method using pure tones coupled with a delayed electric shock. The audible range of tiger shark extended from 80Hz to 300Hz with a peak sensitivity at 80Hz including less sensitivity at 300Hz. The mean auditory thresholds of tiger shark at the frequencies of 80Hz, 100Hz, 200Hz and 300Hz were 90dB, 103dB, 94dB and 115dB, respectively. The positive response of tiger shark was not evident after the sound projection of over 300Hz. At the results, the sensitive frequency range of tiger shark is narrower than that of fish that has swim bladder. In addition, it is assumed that the most sensitive frequency in auditory thresholds of Chondrichthyes is lower than that of Osteichthyes. Critical ratios of tiger shark measured in the presence of masking noise in the spectrum level range of about 60-70dB (0dB re 1μPa/Hz) increased from minimum 27dB to maximum 39dB at test frequencies of 80-200Hz. The noise spectrum level at the start of masking was distributed at the range of about 65dB within 80-200Hz.

This study was investigated seasonal variation and species composition of fish species at artificial reefs (octangle three-stage compartment type and dice type)and natural rock in the Shinyang-Ri coastal waters off Jeju Island with visual census method in January 2009, April 2009, July 2009, September 2009, December 2009, March 2010, June 2010, and September 2010. A total of 44 fish species was occurred, and the dominant fish species were Apogon semilineatus, Chromis notata, Trachurus japonicus, Sebastes thompsoni and Apogon doederleini. The number of individuals of fishes was higher at April 2009 and March 2010, however, lower at June 2010 and September 2010. The number of fish speices was higher at artificial reefs than those of at natural rock. Apogon semilineatus was dominant at octangle three-stage compartment type and the dice type artificial reefs, whereas Chromis notata was for natural rock. These results indicated that artificial reefs were good habitats for a variety of fish species in the Shinyang-Ri coastal waters off Jeju Island.

제주도 연안해역 4개 지역(한림, 애월, 신촌, 함덕) 해수의 온도, 염분농도, 용존산소량(DO), 화학적 산소요구량(COD), 부유물질(SS), 암모니아성 질소(NH3-N), 질산성 질소(NO3-N) 및 아질산성 질소(NO2-N)와 같이 다양한 이화학적 특성을 확인하였다. 해수의 평균 온도는 26.23~28.6℃, 염분농도는 31.4~32.88‰, pH는 8.15~8.35, COD는 0.48~0.91 mg

The forming of fishing ground and the population ecological characteristics of yellowtail, Seriola quinqueradiata, in the coastal waters off Gim-nyeong of Jeju Island were investigated. The stock of yellowtail, Seriola quinqueradiata, between Jeju Island and coastal areas of the East Sea is probably the same. Water temperature probably is a major factor for controlling distribution of yellowtails in deeper, offshore areas off Jeju Island. However, the major factor that determines aggregation of yellowtails in coastal areas of Jeju Island, especially off Gim-nyeong is probably strong tidal currents driven by distribution of yellowtails rather than hydrological conditions such as Yellowtails collected off Jeju Island were from 1 to 4yrs old and about 50% of them were 1-yr old, probably indicating overfishing. Jack mackerel was the major prey item for yellowtails off Gim-nyeong from October to March, suggesting concurrence of the two species.

This paper is to investigate the effect of the immersion time in the traditional hairtail hand line for developing the fishing methods and the fishing gear in the coast of jeju. The operating of 32 times was made with each different immersion time of hairtail hand line, and the relations between the catch and the immersion time were examined. As the result, targeted species rate was over 98% of total catch. From about 800 seconds after casting, the hooking rate was decreased and the bite loss rate was increased, it seems to be made by the decreasing factors of predators including the cutting of branch lines etc. In addition, it was supposed that the hooking rate and the bait loss rate had a deep connection with feeding time zone. The level of the correlation coefficient of the bait loss rate according to the immersion time was 0.54 at p≤0.01, in the case of the hooking rate, 0.59 was chosen after about 800 seconds. The hooking rate and the bait loss rate according to the hook number were not irrelevant to the fish school layer. Additionally, it was assumed that the bait loss rate was related to the depth of water.

This experimental study was carried out to obtain the base data for saving the man power in the fishing operation of largehead hairtail hand line by using the continuous type hand line system with a rotary device which could make a main line move automatically. In order to solve the twists and entangling on the main line happened during operating test, the resistance board was suspended at the end of the main line at sea. As the result, there were no problems of tangling and so on due to up and down moving of a main line. According to the control of a fixed angle of guide roller, it was possible to prevent the main line to be separated from a side roller and a guide roller. In addition, PVC tube between a guide roller and a side roller enabled a main line to be moved smoothly without any entanglement.

유럽 및 미국에서는 안전하며 환경친화적인 연안운송이 활성화되어 있으나 국내의 경우 연안운송에 의한 화물운송은 극히 저조한 실정이다. 본 연구에서는 목포-제주 사이의 해상화물 분석 결과에 기초하여 육상/해상 복합운송시스템을 제안한다. 먼저 목포 및 제주의 반출입 화물 현황을 조사하고 연안항로 및 여객 화물에 대하여 분석한다. 그리고 철도-선박, 트럭-선박의 복합운송과 RORO선 연안운송 등에 대하여 고찰하였다. 마지막으로 목포-제주 항로에 대하여 RORO선을 활용한 연안운송시스템을 제안하고 그 기술적 타당성을 확인하였다.

The fundamental data on the catch fluctuation in the rectangular set net according to the tide age were developed based on the catches recorded from the year 1986 to 2004 in the coastal waters of Hamdeok, Jeju. Total catch by the rectangular set net had a deep connection with the tide age. In particular, during increasing tide, total catch were reduced gradually from the neap tide to the high tide. As it turned out, the slope of total catch declined by degree and showed a correlation coefficient of determination of 0.76. On the contrary, in the case of decreasing tide, there was little sign of rise in total catch. In particular, large catch seemed to occur at the next tide to the neap tide. In the relation between the catch and the tide age, the level of the correlation coefficient chosen at p≤0.05 decreased in the order rabbitfish(-0.84) and horse mackerel(-0.71), while the significance of other dominant species were not selected.

2004년 9월, 11월 그리고 2005년 2월 총 3회에 걸쳐 제주 차귀도 연안해역 10개 정점 표층수와 저층수에서 종속영양세균의 개체수를 조사하였고, 또한 해당 해역 수질의 이화학적 특성을 조사하였다. 2004년 9월, 11월 그리고 2005년 2월에 종속영양세균의 수는 각각 표층수에서는 3.5×101~1.16×103 cfu mL-1, 0.4×101~5.6×101 cfu mL