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.

차량이 운행하는 육상의 도로와 마찬가지로 해상에도 선박의 안전항행을 위 한 여러가지 형태의 항로가 존재한다. 선박의 항행은 특별한 사정이 없는 한 목적지까지 최단거리로 항해해야 하는 원칙하에 수심과 지형 및 통항량을 감안 하여 최적의 항로가 결정된다. 대부분의 연안국들은 자국 연안수역에서의 해상 교통을 원활하게 하고 선박의 안전한 항행을 도모하기 위하여 다양한 형태의 항로를 지정하여 운영하고 있다. 예컨대, 통항분리방식, 교통안전특정해역의 지정, 유조선통항금지해역 및 추천항로의 고시 등이다. 특히, 한국과 일본에서는 추천항로의 형태로 권고적 성격의 항로를 지방청장 이 고시하여 운영하고 있다. 추천항로의 법적근거는 국제협약상 미약하지만 국 내법적으로도 법령의 형태가 아닌 지방청장의 고시로 지정하여 운영하고 있다. 이로 인해 법적지위와 그 성격에 있어 강행력이 부족하고 일반 항해자들의 준 수의무도 미약하다. 이 논문에서는 현행 국내연안 추천항로의 현황과 추천항로지정 제도상의 문 제점 및 법적 지위 등을 호미곶 추천항로를 중심으로 고찰하고, 타 지역의 추 천항로와 비교·분석하여 제도개선을 위한 법제정비 방안을 제시하였다.

We examined monthly changes in the rate of fishes by-caught by gape net with wings and their immature ratio in thecoast of Yeosu and Jindo Island, Korea. A minus correlation between bycatch rate, the ratio of fishes except for anchovy, Engraulis japonicus, to all fishes collected by gape net with wings, and individuals of the collected anchovy was significantly observed, implying that as the anchovy catch decreased and the bycatch rate increased. Immature ratios by the dominant bycatch species during the study is the following; Leiognathus nuchalis was 72.7~99.0%, Sphyraena pinguis was 84.0%, Sardinella zunasi was 90.0%, others (Leptocephalus, Trichiurus lepturus, Ammodytes personatus, Sphyraena pinguis, Trachurus japonicas, Mugil cephalus and Erisphex pottii) were 100.0%. In order to decrease the high bycatch rates of immature fishes in spring and autumn, our study suggested increasing of codend mesh size and developing suitable bycatch reduction devices in a gape net with wings.

The coastal stow net (stow net hereafter) in Korea is one of the major fishing methods for yellow croaker (Larimichthys polyactis), ribbon fish (Trichiurus lepturus), and anchovy (Engraulis japonicus). In terms of energy efficiency, the stow net fishery is more competitive than towing fishing gears such as trawl gears. The fishing vessels in stow net fishery have consumed less fossil fuel and also have had less carbon dioxide emission into the atmosphere. however, the stow net fishery is necessary to be regulated due to its increased output of the fleet. Therefore, it is required for fisheries authorities to manage the fishing capacity or fishing power for the assurance of fishery’s sustainability. For fisheries management authorities, it is necessary to quantify data related to fishing capacity and fishing power to deploy fishery policy in a sustainable way. In terms of data for decision-making, Data envelopment analysis (DEA) method was conducted to estimate fishing capacity. Fishing power index (FPI) was also applied to calculate relative fishing power to approach the problem in a quantitative way.

The purpose of this study is to compare the ichthyofauna between the eelgrass bed waters located in the open sea and the nearby sea free of eelgrass, and this study collected a total of 26 species. Comparing the fish collected on the eelgrass bed (St.2) of Geomun–do coast with the fish collected on the coastal waters (St.1) void of the nearby eelgrass bed, the fish collected from the eelgrass bed included 19 species, 413 individual with 16,110.6g in weight while the fish collected from the coastal waters void of the eelgrass bed included 19 species, 290 individuals with 12,961.5g in weight. Accordingly, it was found that the population size and biomass of the fish collected from the eelgrass bed were higher than the coastal waters void of the eelgrass. This study could identify that diversity, richness, evenness index except dominance were also much higher even in the result of cluster analysis.

This study aims to empirically analyze the relationship between climate change elements and catch amount of coastal fisheries, which is predicted to be vulnerable to climate change since its business scale is too small and fishing ground is limited. Using panel data from 1974 to 2013 by region, we tested the relationship between the sea temperature, salinity and the coastal fisheries production. A spatial panel model was applied in order to reflect the spatial dependence of the ocean. The results indicated that while the upper(0-20m) sea temperature and salinity have no significant influence on the coastal fisheries production, the lower(30-50m) sea temperature has significant positive effects on it and, by extension, on the neighboring areas’s production. Therefore, with sea temperature forecast data derived from climate change scenarios, it is expected that these results can be used to assess the future vulnerability to the climate change.

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.

일반적으로 선박평형수는 선박의 감항성을 향상시키지만 수생 외래 생물의 이동 수단으로서 해양생태계를 교란시키고 있다. 선박평형수로 인한 영향에 관한 연구는 20세기 초 시작되었으며, 1903년 북해에 아시아에서 서식하는 프랑크톤의 서식이 확인되기도 하였다. 공식적으로 평형수로 인한 문제는 1970년부 터 국제사회에 등장하게 되었고 IMO는 1980년 후반부터 MEPC를 중심으로 평형수로 인한 해양환경의 위협 및 생태계의 교란을 방지하기 위한 협약 개발을 시작하였다. 장기간의 노력 결과로 2004년 선박의 평형수와 침전물의 통제 및 관리를 위한 국제협약이 채택되었다. 이 협약은 현재까지 발효되지는 못하였다. 그러나 가까운 시일 내에 발효될 것으로 예상되기 때문에 철저한 이행 준비가 요구된다. 특히, IMO의 선박평형수관리협약에서 정의하는 평형수는 UN해양법협약상 위생과 해양환경오염의 대상이 되기 때문에 국제법적 규제 성격에 있어서 타 선박기인 해양환경 오염물질들과는 상이하다. 따라서 이 논문에서는 이와 같은 규제 성격을 고려한 UN해양법협약상 연안국 관할 수역별 이행방안을 고찰함 으로써 IMO 선박평형수관리협약의 통일된 이행방안을 제안하고자 한다.