한반도 연안의 낫돌고래 혼획 특성 연구

박겸준,김민주,이미경,이종희 한국수산해양기술학회 2023 수산해양기술연구 Vol.59 No.4

본 연구는 2016년부터 2021년까지의 낫돌고래 혼획 자료를 수집, 분석해 최근 한국 연안의 낫돌고래 혼획 특성을 구명하였다. 연도, 월, 체장, 성별, 위도(N), 경도(E), 혼획 어구 정보로 구성된 총 503건의 혼획 자료를 분석에 사용하였다. 혼획이 가장 빈번한 해역은 경도 E 130도 미만의 가까운 연안, 특히 위도 N 35.5도의 남쪽 연안이었으며 위도가 낮을수록 혼획은 증가했다. 2017년 이후 혼획량이 점차 감소하는 경향을 나타냈으며, 혼획되는 낫돌고래의 암수 성비는 암컷 31%, 수컷 40% 미분류 29%로 혼획되는 낫돌고래에서 수컷의 비율이 가장 높았지만 통계적으로 유의한 차이는 없었다(p > 0.5). 계절에 따른 혼획 동향 분석에서는 겨울철에 혼획이 주로 발생하고 있으며 혼획량은 월별로 차이가 있는 것으로 추정되었다(p < 0.01). 낫돌고래는 자망어업에 의해서 주로 혼획되고 그 다음으로 정치망에서 많이 혼획되었는데, 어구에 따른 혼획량의 통계분석에서도 자망에서 유의한 차이를 보이며 혼획이 많은 것으로 추정되었다(p < 0.001). 위도에 따른 체장 조성을 고려했을 때, 낫돌고래가 동해 남부를 양육장으로 이용할 가능성이 있는 것으로 드러났으나 유의한 수준으로 확인되지 않았으며, 향후 세밀한 모니터링과 생태적 조사를 통한 확인이 필요하다. 낫돌고래 혼획의 가장 큰 비중을 차지하는 자망어업은 약 27개 종류가 있으므로 효과적인 보존 관리 대책을 마련하기 위해서는 자망을 더 세부 어업으로 나누어 혼획 관계를 추정하는 연구가 필요하다. This study presents an analysis of bycatch data concerning Pacific white-sided dolphins (Lagenorhynchus obliquidens) along the Korean coast from 2016 to 2021. A total of 503 bycatches were examined, encompassing data on year, month, body length, sex, latitude (N), longitude (E), and fishing gear. Bycatch was the most frequent in waters with a longitude of less than 130°E, particularly in the southern coastal region at a latitude of 35.5°N, with a higher likelihood of bycatch in lower latitudes. Since 2017, a decreasing trend in bycatches has been observed. The sex distribution of bycaught dolphins showed a predominance of males (40%), followed by females (31%), with an unclassified category at 29%, though no statistically significant differences were found (p > 0.05). Seasonal analysis indicated that bycatch predominantly occurred during the winter months, with significant monthly variations (p < 0.01). Pacific white-sided dolphins were primarily ensnared in gill nets and, to a lesser extent, in stationary nets. Statistical analysis by gear type revealed a significant preference for gill nets (p < 0.001). Considering body length composition in relation to latitude, it is suggested that Pacific white-sided dolphins may utilize the southern waters of the East Sea as a potential nursery ground, though this was not confirmed at a significant level, emphasizing the need for further in-depth monitoring and ecological investigations. Given that there are approximately 27 different types of gill nets associated with the majority of bycatches, more detailed research is warranted to divide these gear types into finer subcategories for estimating bycatch relationships, ultimately leading to the development of effective conservation and management strategies.

위성추적장치를 이용한 구조치료 상괭이(Neophocaena asiaeorientalis) 의 이동 모니터링 결과 및 표층수온과의 관계

박겸준,Yamada, Keiko,손호선 한국수산과학회 2018 한국수산과학회지 Vol.51 No.4

Little is known about the movements of finless porpoises Neophocaena asiaeorientalis and their relationship with sea surface temperature (SST). A female finless porpoise that was stranded alive on the shore at Busan was rehabilitated for 16 months at the Sea Life Busan Aquarium. The porpoise was released off Geoje Island with a satellite tag on her mid-ridge and tracking data were received for 7 days. The porpoise moved directly to the southern shore of Gadeok Island, where an earlier study reported that finless porpoises were most abundant around the island. The tracking route revealed two other potential primary habitats. The porpoise moved to the middle of the east coast of the Korean Peninsula at Uljin, beyond the distribution boundary known from earlier studies. Satellite infrared images detected a cold water mass off the Uljin coast and the tracking route showed that the porpoise avoided this low-temperature area.

가덕도 상괭이(Neophocaena asiaeorientalis)의 분포 및 계절적 변화

박겸준,윤영글,신정호,손호선,최영민,Park, Kyum Joon,Yoon, Young Geul,Sin, Jeong-Ho,Sohn, Hawsun,Choi, Young-Min 한국수산과학회 2017 한국수산과학회지 Vol.50 No.5

Few studies on the finless porpoise Neophocaena asiaeorientalis have been conducted on the south coast of Korea. This region includes Gadeok Island, which is located off the Korean peninsula in an area of heavy maritime traffic. Sighting surveys of finless porpoises were conducted at seven predetermined spots around Gadeok Island in January, May, July, September, and November 2016. Finless porpoises (127 individuals in 24 schools) were sighted at all but one (spot P5) of the survey locations. Fewer porpoises were spotted in summer (Jul and Sep) than in other seasons (P<0.05). Porpoises were most abundant around the south coast of the island, where they were spotted in every season, and in significantly higher numbers than at other locations (P<0.05). Single individuals accounted for 20.8% of sightings, while 25.0% of sighted schools consisted of only two porpoises. The mean school size was 5.29 individuals (SD=6.72).

한국 서해 상괭이 (Neophocaena asiaeorientalis)의 먹이습성과 섭식량

박겸준,안용락,이영란,박지은,문대연,최석관 한국수산과학회 2011 한국수산과학회지 Vol.44 No.1

We investigated the stomach contents of finless porpoises collected in the Yellow Sea. Prey organisms in the stomachs of 109 finless porpoises were identified as 11 species of fish, 8 species of shrimp and 4 species of cephalopod. Index of Relative Importance analysis revealed that the porpoises fed mainly on the Japanese sand shrimp (Crangon affinis). The energy density of the prey was estimated to be 5.46 kJ. The daily energy requirement was estimated to be 18,051 kJ/day for a porpoise with an average weight of 32.49 kg. The estimated annual consumption by finless porpoises in the Yellow Sea was 25,454 tons. The average commercial catch in the Yellow Sea by Korean fisheries was 135,913 tons from 2005 to 2009. Assuming that the abundance of finless porpoises is stable, porpoises ate approximately 18.7% of the commercial catch. The fishery catch may be influenced by the consumption by finless porpoises, while fishery bycatch is a cause of porpoise mortality in the Yellow Sea.

Line Transect에서 발견율함수 추정에 사용되는 모델에 따른 상괭이, Neophocaena phocaenoides의 자원개체수 추정

박겸준,김장근,장창익 한국수산과학회 2007 한국수산과학회지 Vol.40 No.4

한국 서해 상괭이의 먹이 습성과 영양 단계

박겸준 부경대학교 수산과학연구소 2003 硏究業績集 Vol.27 No.-

새만금에서 발생한 상괭이(Neophocaena asiaeorientalis)의 대량 폐사: 이상 저온에 따른 영향의 증거

박겸준,안두해,임채웅,이태호,김두남 한국수산과학회 2012 한국수산과학회지 Vol.45 No.6

On 3 February 2011, a mass mortality of finless porpoises Neophocaena asiaeorientalis occurred at a dike of the Saemangeum Sea dike. A total of 249 carcasses were collected; these had been stranded by a sea dike and had floated into the lake formed by the dike. Eight bodies were measured, and four of these were dissected to analyze stomach contents. The blubber thicknesses of five bodies were compared with those of caught finless porpoises in the Yellow Sea from 2010. Finless porpoises at the Saemangeum Sea dike exhibited better nutritive conditions than finless porpoises in the Yellow Sea. Air temperature in January 2011 was lower than the prior 5-year average (P<0.05). Water temperature when the mass mortality occurred was lower than values observed in 2009 and 2010: values below 0°C had been recorded, and the majority of the dike lake had frozen over. The mass mortality of finless porpoises may have been caused by these unusually low temperatures.

A New Abundance Estimate for the Finless Porpoise Neophocaena asiaeorientalis on the West Coast of Korea: An Indication of Population Decline

박겸준,손화선,안용락,김현우,안두해 한국수산과학회 2015 Fisheries and Aquatic Sciences Vol.18 No.4

The west coast of Korea is the largest habitat for finless porpoises, with approximately 36,000 individuals reported in 2005 (Park et al., 2007). To date, there have been no subsequent finless porpoise population estimates. However, in recent bycatches, finless porpoises accounted for the highest proportion of all cetaceans and have been reported to be most frequently caught on the west coast of Korea (Kim et al., 2013). The present study, conducted in 2011, enumerated finless porpoises inhabiting the west coast of Korea using a line transect survey in offshore and inshore regions to assess variations in their abundance. In offshore regions we found the population density of finless porpoises to be 0.122 ind./km2, whereas it was 0.565 ind./km2 in 2004. In inshore regions, the population density of finless porpoises was 0.151 ind./km2, whereas it was 0.638 ind./km2 in 2005. Therefore, we estimate that the population densities of finless porpoises in both offshore and inshore regions of the west coast of Korea decreased by approximately 70% between 2004/2005 and 2011. It is imperative to mitigate the bycatch of finless porpoises and protective action is urgently needed in the near inshore regions.

새만금 호의 상괭이 대량 폐사 후 상괭이(Neophocaena asiaeorientalis) 재출현과 분포 경향

박겸준,이승용,안용락,김현우,안두해,김두남,김영혜 한국수산과학회 2014 한국수산과학회지 Vol.47 No.6

A mass mortality of 249 finless porpoises Neophocaena asiaeorientalis occurred in the Saemangeum Dyke in February 2011. It was an extraordinary event, notable due to the death toll and the location of the occurrence, a semi-isolated lake enclosed by a man-made structure. We conducted sighting surveys that consisted of a land-based sighting survey recorded from three different platforms, and a ship-based sighting survey in the lake. The land-based survey was dedicated to clarifying the distribution of finless porpoises and whether they passed through two water gates (Shinsi and Garyek) of the dyke from 2011 to 2013. No finless porpoises were observed in the 2011 or January 2012 surveys. In April 2012, two months and one year after the mass mortality, one finless porpoise, swimming 400 m from the Shinsi water gate, was observed by a land-based survey. The number of observed individuals increased to nine in 2012 and reached 10 by May 2013 at the time of the surveys. Most of the porpoises were detected near the Garyek water gate. The density of the animals was 0.075/km2 in 2012 and 0.083/km2 in 2013. The density of porpoises was 2.063/km2 at the time of the mass mortality.

한국 서해에서 상괭이(Neophocaena asiaeorientalis)의항공 조사 타당성

박겸준,손호선,김영혜,김두남,김현우,안두해,안용락 한국수산과학회 2013 한국수산과학회지 Vol.46 No.6

Vessel-based sighting surveys for cetaceans have been conducted in Korean waters since 2000. The supporting data estimate the abundance of finless porpoises along the west coast of Korea; however, they are insufficient because of the coverage and frequency of the surveys. A preliminary aerial survey was conducted in 2011, and the results were assessed with respect to a sighting survey operated by a research vessel in order to compare effectiveness and potentiality. A total of 110.00 nautical miles of effective efforts were made with three sightings under Beaufort scale 4 in the aerial survey, while the vessel-operated survey covered 403.38 nautical miles over 7 days without any sightings under Beaufort scale 4. The standard deviation of the altitude in this survey was 22.7m, which was significantly higher than that of the referenced study of 4.3 m.