https://repository.kopri.re.kr/handle/201206/5291 2026-03-07T09:07:18Z 2026-03-07T09:07:18Z Lee, Won Young Kim, Jeong-Hoon https://repository.kopri.re.kr/handle/201206/7409 2022-03-24T07:11:48Z 2015-01-01T00:00:00Z

Title: Chinstrap penguin foraging area associated with a seamount in Bransfield Strait, Antarctica Authors: Lee, Won Young; Kim, Jeong-Hoon Abstract: Identifying marine features that support high foraging performance of predators is useful to determine areas of ecological importance. This study aimed to identify marine features that are important for foraging of chinstrap penguins (Pygoscelis antarcticus), an abundant upper-trophic level predator in the Antarctic Peninsula region. We investigated the foraging locations of penguins breeding on King George Island using GPS-depth loggers. Tracking data from 18 birds (4232 dives), 11 birds (2095 dives), and 19birds (3947 dives) were obtained in 2007, 2010, and 2015, respectively. In all three years, penguins frequently visited an area near a seamount (Orca Seamount) in Bransfield Strait. The percentage of dives (27.8% in 2007, 36.1% in 2010, and 19.1% in 2015) and depth wiggles (27.1% in 2007, 37.2% in 2010, and 22.3% in 2015) performed in this area was higher than that expected from the size of the area and distance from the colony (8.4% for 2007, 14.7% for 2010, and 6.3% for 2015). Stomach content analysis showed that the penguins fed mainly on Antarctic krill. These results suggest that the seamount provided a favorable foraging area for breeding chinstrap penguins, with high availability of Antarctic krill, possibly related to local upwelling.

2015-01-01T00:00:00Z Takahashi A Mori Y Shin, Hyoung Chul Kokubun N https://repository.kopri.re.kr/handle/201206/6141 2022-03-24T07:11:28Z 2008-01-01T00:00:00Z

Title: Krill-feeding behaviour of gentoo penguins as shown by animal-borne camera loggers Authors: Takahashi A; Mori Y; Shin, Hyoung Chul; Kokubun N Abstract: Animal-borne camera loggers were used to examine the patterns of prey encounter and feeding behaviour of gentoo penguins at King George Island, Antarctica. The still images from the camera loggers showed that the penguins encountered the swarms of krill for 25.5% (range: 8？38%) of their dives (>5 m) on average, during their foraging trips (mean duration of 5.4 h, n = 7 trips). They encountered krill swarms during the dives to 10？70 m depth, in pelagic as well as benthic habitats. In the benthic habitat, the penguins swam just above the sea Xoor and headed downward over a krill swarm, probably using the sea floor to assist them to feed on mobile swarms. The shallow coastal waters would be the important foraging habitat of gentoo penguins breeding in King George Island.

2008-01-01T00:00:00Z Keun, Khim Boo Yi Wang 장양희 Hong, Chang-Su Sigman D Shin, Hyoung Chul https://repository.kopri.re.kr/handle/201206/6672 2022-03-24T07:10:47Z 2008-01-01T00:00:00Z

Title: Variation of Nitrate Concentrations and δ 15N Values of Seawater in the Drake Passage, Antarctic Ocean Authors: Keun, Khim Boo; Yi Wang; 장양희; Hong, Chang-Su; Sigman D; Shin, Hyoung Chul Abstract: Seawater samples were collected at discrete depths from five stations across the polar front in the Drake Passage (Antarctic Ocean) by the 20th Korea Antarctic Research Program in December, 2006. Nitrate concentrations of seawater increase with depth within the photic zone above the depth of Upper Circumpolar Deep Water (UCDW). In contrast, δ 15N values of seawater nitrate decrease with depth, showing a mirror image to the nitrate variation. Such a distinct vertical variation is mainly attributed to the degree of nitrate assimilation by phytoplankton as well as organic matter degradation of sinking particles within the surface layer. The preferential 14NO3- assimilation by the phytoplankton causes 15NO3 concentration to become high in a closedsystem surface-water environment during the primary production, whereas more 14NO3 is added to the seawater during the degradation of sinking organic particles. The water-mass mixing seems to play an importantrole in the alteration of δ 15N values in the deep layer below the UCDW. Across the polar front, nitrate concentrations of surface seawater decrease and corresponding δ 15N values increase northward, which is likelydue to the degree of nitrate utilization during the primary production. Based on the Rayleigh model, the calculated ε (isotope effect of nitrate uptake) values between 4.0 and 5.8 were validated by the previously reported data, although the preformed δ 15NO3 initial value of UCDW is important in the calculation of ε values.

2008-01-01T00:00:00Z Kim, Suam Hewitt RP Shin, Hyoung Chul Kang, Donhyug Kawaguchi S Lee, Y.H. Quinones J Takao Y Gutierrez M Naganobu M https://repository.kopri.re.kr/handle/201206/6247 2022-03-24T07:11:18Z 2004-01-01T00:00:00Z

Title: Variation in the biomass density and demography of Antarctic krill in the vicinity of the South Shetland Islands during the 1999/2000 austral summer Authors: Kim, Suam; Hewitt RP; Shin, Hyoung Chul; Kang, Donhyug; Kawaguchi S; Lee, Y.H.; Quinones J; Takao Y; Gutierrez M; Naganobu M Abstract: Vessels from Japan, Peru, and the USA conducted four sequential surveys designed to estimate the biomass density and demography of Antarctic krill in the vicinity of the South Shetland Islands between late December 1999 and early March 2000. The surveys were conducted during the same austral summer as the CCAMLR 2000 Survey in the Scotia Sea (Watkins et al., Deep-Sea Research, II, this issue [doi: 10.1016/j.dsr2.2004.06.010]), and the data were analyzed in a similar manner. Biomass densities were not significantly different between the surveys and averaged 49 g m？2. Maps of krill biomass indicate three areas of consistently high density: one near the eastern end of Elephant Island, one mid-way between Elephant Island and King George Island, and one near Cape Shirreff on the north side of Livingston Island. The areas of highest krill density appeared to move closer to the shelf break as the season progressed. This apparent movement was accompanied by a change in the demographic structure of the population, with smaller krill absent and a larger proportion of sexually mature animals present in late summer.

2004-01-01T00:00:00Z