This study analyzed the catch data of Chionoecetes japonicus in the offshore trap fishery from 2009 to 2022 to investigate the spatial distribution changes of fishing grounds in the East Sea. The results showed that the center of the fishing grounds consistently shifted offshore and northward from 2009 to 2020, but moved back towards the coastal areas since 2020. When comparing the catch of C. japonicus from the offshore trap fishery between 2009-2015 and 2016-2022, statistically significant differences were found (p<0.01). Analysis of the center of the fishing grounds revealed that they gradually shifted offshore while the fishing grounds were initially concentrated in the coastal areas of the East Sea. This suggests that the center of the fishing grounds moved offshore and northward as the C. japonicus in the coastal fishing grounds decreased. The shift of the fishing grounds back towards the coastal areas since 2020 is attributed to the increased operational costs due to the soaring fuel prices and the impact of the COVID-19 pandemic, which led to a decline in consumer demand for live seafood consumed in restaurants. Consequently, the offshore trap fishery for C. japonicus shifted their focus from offshore areas, which required higher operational costs due to increased fuel consumption and longer fishing times, to coastal areas, that were relatively less costly. This study is the first scientific results of its kind to investigate the formation of fishing grounds and annual changes in the fishing grounds of C. japonicus caught in offshore trap fishery in the East Sea from 2009 to 2022.

본 연구에서는 울진군 대형산불 발생이 연안해역에 미치는 영향을 파악하기 위하여 울진군 나곡(F-1), 후정(F-2), 봉평(F-3), 공세 항(F-C)에서 수질과 함께 해조류의 종조성, 우점종 및 군집 특성을 분기별로 조사하였다. 수질 분석 결과, 산불에 대한 영향을 판단하기 위한 수소이온농도(pH)는 표․저층에서 각각 8.07~8.30과 8.12~8.48 이었다. 본 연구의 pH 값은 동해의 연안 해수에 있는 일반적인 농도 범 위에 포함된 값으로 산불로 인한 직접적인 영향으로 볼 수 없었다. 연안 조하대에서 조사한 해조류의 분석 결과, 전 시기에 대한 해조류 의 종조성 비율은 홍조류(58.1%) > 대롱편모조류(갈조류, 25.8%) > 녹조류(14.5%) > 현화식물(1.6%) 순이었다. 시기별 해조류의 우점종은 3 월과 6월에 나곡(F-1)과 후정(F-2) 해역에서 대롱편모조류(Ochrophyta, 갈조류)의 미역(Undaria pinnatifida)이 가장 우점하였다. 9월과 11월은 봉평(F-3) 해역과 공세항(F-C)에서 각각 홍조류(Rhodophyta)인 우뭇가사리(Gelidium elegans)와 혹돌잎류(Lithophyllum sp.)가 가장 우점하였다. 군집분석에서는 그룹이 계절에 따른 특정 해조류의 출현 유무에 따라 2개(A, B)로 나누어졌다. 우점종은 그룹 A에서 미역, 우뭇가사리, 미 끈뼈대그물말, 그룹 B는 주로 혹돌잎류가 출현하였다. 따라서, 연구지역의 해조류 종조성과 군집구조는 전형적인 수온에 따른 계절변화 와 함께 대조구와의 유의미한 차이도 보이지 않아서 산불에 의한 영향은 나타나지 않았다.

Changes in the fishing grounds for four drag-bagnet fisheries (large trawl, large pair trawl, large Danish seine and middle Danish seine) were investigated by year and sea-blocks in Korean waters. We used catch and effort data by sea-block (latitude × longitude: 30´ × 30´) of the National Institute of Fisheries Science (NIFS) and yearly fishing production statistics of the Korean statistic information service from 2008 to 2014. The main benthic habitat of fishing ground was sand and sandy mud material. The average swept areas for the four fisheries were 181.7 km2, 606.4 km2, 2,720.9 km2 and 252.8 km2, respectively. The main fishing ground was around Jeju Island and the eastern South Sea. The main fishing ground moved to the northern part of the South Sea during the study period due to a closure of fishing grounds and changes in the target species.

We collected AIS information on fishing vessels operating near Jeju Island, and analyzed appearance density of the Chinese fishing vessels and inferred the movements of the fishing grounds. AIS information was received from October 16, 2016 to October 16, 2017 and stored on a hard disk through a program called AisDecoder. Unauthorized fishing vessels within the Exclusive Fisheries Agreement Zone (EFAZ) operated near the EFAZ boundary, and the frequency of appearance of fishing vessels were high in the middle waters of Korea and Japan, 252 and 250 fishing zones. Chinese fishing vessels authorized to enter appeared scattered outside the Prohibiting Fishing Zone of the Large Trawlers (PFZLT), and the closer they were to the PFZLT boundary, the higher the appearance density. And the appearance of Chinese fishing vessels with a speed from 0 to 3 knots was mostly outside the EFAZ, showing high density in the waters close to the boundary between Korea and Japan. On the other hand, within the EFAZ, the frequency of appearance of Chinese fishing vessels was also low and scattered. The appearance of Chinese fishing vessels with a speed from 3 to 5 knots mostly shows some variability within the EFAZ, but the frequency of appearance was high and the density was high. The seasonal appearance of Chinese fishing vessels in the waters south of Jeju Island appeared in the southwest in the autumn and then moved south and southeast of Jeju Island in the winter, and in the spring and summer. They were considered going to other fishing grounds without fishing in the waters south of Jeju Island.

This study is to excavate superior fishing communities by applying the Ostrom (1990)’s principles of sustainable and successful use of common goods. Ostrom(1990)’s principles are (1) clearly defined boundaries (2) congruence between appropriation and provision rules and local conditions, (3) collective choice arrangements (4) monitoring (5) graduated sanctions (6) conflict-resolution mechanism (7) recognition of rights to organize by external government authorities (8) nested enterprises. The survey was carried out under the individual interview method of 15 fishing village members in 32 fishing communities with the government’s fishery environment improvement and fishery creation projects. The total effective samples are 477. These data were analyzed. The analysis result shows that 24 fishing villages are selected among the 32 fishing communities in the samples, including Nanji, Sanghwang, Songseok, Sinshido, Jukyo, Jinsan, Changli, Pado, Beopsan, Rahyang, Palbong, Woongdo, Daehwang, Sapsi, Chido, Jinri, Daeri, Songgak, Joongwang, Ojii, Doripo, Doseong, Mongsan 1ri and Songnim as superior fishing villages. The results of this study have limitation that may vary depending on the rigor of the criteria in the process of deriving good fishing communities. Despite this limitation, this study has expanded existing research focused on validating the theoretical applicability of the framework through case analysis of specific fishing communities to objectively and quantitatively to many fishing communities. The results of this study are expected to contribute to the creation of conditions in which fishermen can continue to manage their fishing grounds and stand on their own feet by presenting the framework and principles for developing desirable fishing village models for the continued use of mudflat shells grounds as the common goods.

Annual and monthly pollock catches, CPUE and fishing grounds in the high seas of Bering Sea between 1984 and 1992 were analyzed for centroid distribution and bivariate ellipses of trawlers of South Korea, Japan, Poland and China. The catch amount differed by country as 56.1%, 21.7%, 20.4% and 1.8% were caught by Japan, Korea, Poland and China respectively. Japan recorded the highest mean CPUE at 5.7 ton/hour while it was 4.3 ton/hour for Poland, 3.9 ton/hour for Korea and 2.4 ton/hour for China. Cumulative catch varied by month, with the minimum of 137,000 ton in March and the maximum of 848,000 ton in December. Monthly mean of CPUE was the lowest in February (2.0 ton/hour) and the highest in November (6.3 ton/hour). The centroid distribution of monthly fishing ground was located at a southern spot (56° 05'N, 178° 55'E) in January, and it moved anti-clockwise toward 56° 37'N, 178° 24'E in December. Fishing grounds were scattered more by the east-west direction than by the south-north direction. The fishing grounds were similar for Korean, Japanese and Polish trawlers, but Chinese trawlers that fished only from July to December showed distinctively different fishing grounds from the others.

Korean large purse seine fishery catches chub mackerel, sardine, jack mackerel, Spanish mackerel, etc. which are mainly pelagic fish species. The proportion of chub mackerel was 60% over in Korean large purse seine fishery. Sea surface temperature (SST) increased 0.0253℃ per year and total rising rate was 0.759℃ from 1980 to 2009 in the southern sea of Korea, where is mainly fishing grounds of Korean large purse seine. It was that p〈0.01 level was statistically significant. It is northward movement that the center of fishing grounds of chub mackerel by Korean large purse seine fishery moved 4.57km/yr. It was rapidly northward movement about 7.1km/yr, 8.13km/yr to move Spanish mackerel and bluefin tuna fishing grounds. However, the fishing grounds of jack mackerel were moved further south in the 2000s than the 1980s. Catch of tunas and bluefin tuna consistently increased in Korean waters. There was a significantly positive correlation between SST and catch of bluefin tuna in the fishing grounds of Korean waters.

1. 제주해협에서는 6월에 가장 낮은 생물량 분포를 나타내었고, 가을철(11월)에 가장 높은 생물량 분포를 보이면서 높은 2차 생산력을 보이는 것으로 사료된다. 2. 해황 및 습중량과의 관계에서 가장 높은 분포를 나타내는 정점은 각각 정점 14와 11로 그 출현위치는 해협의 중앙부분이고, 한국남해연안역 및 제주도 북부연안역에는 다소 낮은 생물량분포를 보이고 있으며, 생물량 분포가 높게 나타나는 해역의 특징은 patch의 형태로 분포하였다 반면 한국남해연안역에 비하여 제주도 북부연안역에높은 생물량 분포를 나타냄으로써 제주해협에서의 갈치어장 형성위치와 생물량 분포와의 관계가 밀접하게 나타날 것으로 판단된다. 그리고, 가을 의 해황 특성인 서로 다른 이질수괴의 경계역인 안상부 해황의 중심에 높은 생물량을 나타냈다. 3. 제주해협에서 patch의 형태로 생물량 분포가 높게 나타나는 해역의 외측에 좋은 갈치어장이 형성되었다.

The study on the Assembling Mechanism of the Hairtail, Trichiurus lenpturus, at the Fishing Grounds of the Cheju Strait had been investigated by analyzing the relationship of the oceanographic conditions and the fishing ground of the Hairtail in the Cheju Strait. 1. The fishing grounds of the hairtail at the Cheju Strait are formed at the bottom of a high temperature of the tidal front at the coast. area of northern Cheju Island, the tip of the linguiform is high in salinity at the eastern and western entrances of Cheju Island, low salinity eddy on the surface and its surrounding front, various water masses in the Strait and coastal waters of the South Sea in Korea. 2. The fishing grounds of the Hairtail at the Cheju Strait begins with the sea surface temperature higher than 15℃ and the incoming of low salinity water now from the East China Sea. 3. Estimation of optimum temperature and salinity per season based upon analysis for relationship between temperature of water and salinity of the bottom layer and the catch is : 15.2~16.4℃, 34.20~34.40‰ in spring(June); 14.4~ 17.0℃, 33.70~34.30‰ in summer(July~September); and 15.7~ 18.6℃, 33.70~34.50‰ in autumn(October~December). Hairtail are mostly caught at the Yellow Sea Warm Current and Tsushima Current with temperature over 14.5℃ and salinity over 33.70‰ at the bottom layers of the Cheju Strait. 4. Considering the relationship between the amount of hairtail catch and the water temperature of bottom layer, when the bottom water being above 14.0℃ flowed into Cheju Strait through the western entrance of the strait in summer, the ca-h appears to have been abundant. In contrast, the catch has been poor when the temperature of such water was recorded to be below 13℃ Therefore, distribution patterns of water at the bottom layer can be used as a forecast index whether the catch of a certain year will be good or poor.

우리 나라 주변어장에서의 주요 어자원중 조기류가 수동어탑을 위한 대표적 어종으로 부각되었다. 음원수준을 150~180dB로 가정했을 때 선배열 형의 수동어탐기에 탐지될 수 있는 거리는 최저 3km에서 최대 20km 이상으로 추정되어 어탐거리의 획기적 증대가 기대된다. 뿐만 아니라 조기류가 내는 700~800Hz 사이의 tocal noise의 특성은 수동형 어탐기에 의한 어종식별 거리 및 정밀도를 보다 향상시킬 것임이 분명하다. 다만, 이 수동소나를 조기류외에 대형어군을 이루는 멸치, 칼치, 명태류, 쥐취류, 오징어 등에 적용 여부를 가늠하기에는 보다 많은 정량적 자료가 수집된 연후에 가능할 것으로 믿어진다.

동지나해에 있어서 고등어류 어획량 즉 자원량 변동에 따른 어장분포범위의 변동상태를 파악함과 동시에 이에 따른 환경변화와의 관계를 조사하였다. 어획자료는 일본국 농림성조사부 및 국립수산진흥원의 해구별 선망어획량 통계자료를 사용하였다. 이중에서 어획량이 적었던 1968년, 가장 많았던 1974년과 그 후 다시 적어졌던 1980년에 대하여 어획량을 계절별로 집계하여 분석하였다. 해양관측자료는 일본기상청과 국립수산진흥원의 자료를 사용하였다. 그 결과, 고등어류 어장분포는 어느 계절이나 3개년 모두 동지나해 중앙부를 중심으로 북동부와 남서부로 분리되었다. 또한 동계와 춘계에는 쿠로시오역 내측에 폭이 좁은 띠모양[대상]의 어장이 형성되었다. 어군의 북상시기인 하계와 남하시기인 동계에는 한국연안과 쓰시마난류역을 따라서 어장이 형성되었다. 어장분산은 하계가 제일 크고 춘계가 가장 적었으며, 누년 큰 변동이 없었으나 자원량이 많았던 1974년 이후인 1980년이 가장 컸다. 어장의 집중과 분산은 수온약층과 수온의 수평기울기의 크기와 관련이 있었다.

동지나해.황해의 최근 10개년간(1970~1979) 안강망에 의한 참조기.강달이 어획자료를 이용하여 어획량.어장의 경년변동과 저층수온과의 관계를 조사하였다. 그 결과, 1970~1976년간의 어획량은 수온보다 2~3년 늦은 위상(Time lag)을 가지고 변화하였다. 1970~1973년은 감소, 1974년 초~1975년 말은 급격한 증가, 그리고 그 후 1976년 말까지는 평형상태이었다. 그러나 1976년 이후에는 어획노력량의 증가로 인하여 이러한 위상을 가지는 경형은 명확하지 않았다. 또한, 수온이 평년 보다 낮았던 저수온 년인 1977년의 어장분포는 수온이 높았던 고수온 년인 1972년보다 남쪽으로 치우쳐 있는 경향을 보였다