초록 ▼

남극해 유용생물자원 개발연구는 생태계 기반 자원 관리 방안 대두와 더불어 강화되는 보전 일변도의 남극해 수산자원 관리 논리에 대안을 제공하기 위한 연구, 특히 크릴 자원의 허용가능어획량 유지 및 확대를 위한 연구를 수행하고 생명공학적 기술을 이용, 남극해 생물자원을 새로운 용도로 활용하기 위한 연구 개발 수요를 일부 담당함.
◦ 주요 어장인 대서양 측 남극해에서 크릴 동태는 해마다 큰 폭으로 변하며 해빙 분포와 기상의 자연적인 환경요인이 결정적 역할을 함.
◦ 크릴 자원량 자체보다 환경요인에 의한 재배치 효과가 주어진 해

남극해 유용생물자원 개발연구는 생태계 기반 자원 관리 방안 대두와 더불어 강화되는 보전 일변도의 남극해 수산자원 관리 논리에 대안을 제공하기 위한 연구, 특히 크릴 자원의 허용가능어획량 유지 및 확대를 위한 연구를 수행하고 생명공학적 기술을 이용, 남극해 생물자원을 새로운 용도로 활용하기 위한 연구 개발 수요를 일부 담당함.
◦ 주요 어장인 대서양 측 남극해에서 크릴 동태는 해마다 큰 폭으로 변하며 해빙 분포와 기상의 자연적인 환경요인이 결정적 역할을 함.
◦ 크릴 자원량 자체보다 환경요인에 의한 재배치 효과가 주어진 해역에서 발견되는 크릴의 양과 분포를 결정함. 특히 겨울의 광범위한 해빙은 크릴의 은신처를 제공하고 여름철 크릴 어군 공급에 기여함.
◦ 크릴 어업은 대체적으로 일정 수심대 주변에서 이루어지고 크릴을 먹이로 이용하는 자연포식자와 경쟁은 크지 않음.
◦ 따라서 크릴 자원의 어획 제한을 통해 생태계 균형을 유지하는 것은 크릴 어획량이 급속하게 증가하는 경우가 아니면 현실적이지 않음.
◦ 원격 탐사로 관측할 수 있는 거시적 환경요인의 조합에 의해 크릴 자원의 중장기 동태를 예측하고 단기크릴 어황 예보를 시도할 수 있는 체제를 구축하는 것이 가능하리라 기대됨.
◦ 남극 대구 결빙방지 물질 유전자가 검색, 파악되어 잠재력을 입증했고 크릴 기원 지방산도 크릴의 활용도가 확대될 수 있음을 보여줌.

Abstract ▼

4. Results
A. Antarctic krill distribution and oceanography in the southwestern Scotia Sea and the vicinity of South Shetland Islands
Higher density krill aggregations were mostly found on the continental slope (1000 to 2000 m depth) at northern central part of the South Shetland Islands durin

4. Results
A. Antarctic krill distribution and oceanography in the southwestern Scotia Sea and the vicinity of South Shetland Islands
Higher density krill aggregations were mostly found on the continental slope (1000 to 2000 m depth) at northern central part of the South Shetland Islands during late in December. In mesoscale area between Elephant island and South Orkney island, higher density krill patches appeared at around 1000 m depth in mid-December. biomass density to the north of the South Shetland Islands during early summer 2001/2002 was within the range of previous years but there were much less krill to the south of the South Shetland Islands than usual years. Water masses from T/S diagram were classified 5 categories - northern part of Polar Front, Polar Front. Antarctic Circumpolar water, Weddell Sea, Bransfield Strait water. The physical properties at western transect in hydrographic station between King George island and Elephant island depend on the water of the Bransfield Strait. On the other hand, Weddell Sea water flow into the upper water column at the eastern transect.
B. Distribution of Antarctic krill around South Shetland Islands and the consequences for krill predators during 2001/2002 summer
During early summer (early to mid December) krill were scarce with very few swarms to the south of the South Shetland Islands (SSI). Krill density was also low between King George island and Elephant Island. Between Elephant Island and South Orkney Island, on the other hand, krill swarms of average density were present. During late December, krill density to the north of the SSI was at its usual level, and particularly high to the north of Livingston Island. Surface chlorophyll concentrations, which were comparable to the past summers, did not seem to bear any significant relationship to the krill distribution. Low breeding success of gentoo penguins is probably due to the krill scarcity in the Bransfield Strait. This may have resulted from the weaker-than-usual inflow of Antarctic Circumpolar Current into the Bransfield Strait and consequent poor supply or late arrival of krill. For the areas other than north of the SSI, such as the area between Elephant Island and South Orkney Islands, and the eastern part of Bransfield Strait, Weddell Sea may be more important in supplying krill to the areas.
C. Acoustic survey of Antarctic krill around South Shetland Islands and toward Antarctic Peninsula during early summer
High density krill were observed only in the offshore waters in the north of South Shetland Islands. Generally krill density in the west of Antarctic Peninsula was far lower. In general, krill biomass is expected to be lower than average years.
D. Differing levels of krill density over mesoscale area in the southwest Atlantic sector of Southern Ocean during early summer; possible causes and consequences
An acoustic survey detected a krill scarcity in the Bransfield Strait during early summer 2001/2002, however, the area west of South Orkney Islands exhibited a density similar to other years. It has been reported that the abundance of krill in different parts of the Southwest Atlantic sector of the Southern Ocean are linked, influenced by the same gross physical and biological factors, and the krill biomass within a season does not vary greatly. There may be, however, within-season, and regional variability of krill densities. The krill then in these two areas may have been supplied from different sources or may be responding to local conditions. Chlorophyll biomass does not explain the different levels of krill biomass density but the temporal, spatial change of chlorophyll gives a clue. Krill have been suspected of being transported in water currents, and may have arrived in the Bransfield Strait from upstream, later than in usual years. On the other hand, krill found west of the South Orkney Islands may have originated from the Weddell Sea, which might be another predictable wintering ground for krill and hence a source of krill supply.
E. Characterization of aggregations of Antarctic krill and the linkage with environmental variabilities
Krill seem to form well-separated, dense aggregations close to the ice edge, and these tend to turn into layers that are more diffuse and interweaving in offshore waters. This may represent a response to a spectrum in food condition, from concentrated, pulsed to more dilute, well-spread supplies. Sea ice, harboring krill during winter and releasing krill during summer, plays a critical role in re-distributing krill.
F. Utilization of krill fisheries data
Krill fishery is conducted in three major grounds, namely South Shetland Island, South Orkney Islands and South Georgia Island areas. Fishing efforts migrate northward as winter approaches. There appeared to be preferred fishing locations by krill vessels and these tended to scatter around 500 m isobath. CPUE greatly varied between fishing nations and also between years and by areas. CPUE is not likely to be a direct measure the krill availability. Heavy sea ice seems to directly impact the timing and location of krill fishing ground formation. But sea ice condition could cause more inherent changes in the ecosystem and krill population and then krill fishery might respond to this.
G. Genetic analysis of the dynamics of Antarctic krill stocks near the South Shetland Islands
DNA sequences of the mitochondrial gene, COI, showed single nucleotide polymorphisms in 56 out of 636 positions of the examined region. Such differences formed 66 haplotypes, most of which were singletons. The haplotypes were grouped into four types (A, B, C, D). The large number of haplotypes from the 86 individauals indicates that the genetic composition of the krill is diverse. On the other hand, the gene sequences did not show any distinction in terms of their sampling sites and time, indicating that there seems to be a single genetic stock of the krill in the studied area.
H. Digestive gland of Antarctic krill as an indicator of feeding activity
Relative size of digestive gland as a proportion of carapace length and its color can be used as indices of recent feeding activity and prey types. Data from field caught specimens indicate detectable differences in these indices reflecting variable food environment. Starvation and feeding experiments demonstrate that digestive gland accumulate the recent feeding activity of the animals in temporal scale from days to weeks. Determination of the gland size and color over a range of time and space will yield a great deal of useful information regarding the varying food environment and the response of the animals to those changes.
I. Sea ice distribution in the Southern Ocean for the past 5 summers
Sea ice distribution in the Southern Ocean displayed a distinct seasonal pattern. Sea ice starts a considerable retreat from December and reaches a lowest level in February. Nevertheless, inter-annaul variation and regional variation in its extent were substantial.
J. Surface chlorophyll distribution in the Southern Ocean for the past 5 years
Surface chlorophyll distribution in the Southern Ocean for the past 5 years is described using the SeaWiFS data. The distribution displayed a distinct seasonal pattern and significant inter-annual and regional variation.
K. Concurrent examination of sea ice and surface chlorophyll in relation to krill population
Some coastal bays are regularly and predictably covered with sea ice and exposed with ice re-retreat during summer. These areas normally experience enhanced chlorophyll level. These areas, Marguerite Bay, Weddell Sea, Ross Sea, Prydz bay, may be critical for maintaining and supplying krill population to the rest of Southern Ocean. In-depth analysis of these target areas will improve our understanding of the mechanisms how this is maintained and the roles these areas play in governing krill population.
L. Utilization and management of krill resources
A variety of techniques were developed to utilize krill and this resulted in more than 300 patents registered. A package to comprehensively utilize krill and some of their features and marketing may result in realization of krill's potential and an expansion of krill fishery. Currently krill's catch limits are determined by CCAMLR in a conservative way that decline of the target population is highly unlikely and also a sufficient amount is left for the predators. More strict management regimes are likely to be brought into place.
M. Prospects for Korean krill industry
Korean catch of Antarctic krill is now topping the list. Ecosystem based resources management has become the norm to follow and adhere to. Researches to market the new ways to utilize krill to its full potential are warranted, still innovative operation of the krill fleets based on ecological knowledges and information is required and demands further research.
N. Lipids and fatty acid from Antarctic krill
The overall lipid content of E. superba was 72 mg/g dry mass similar to the reported values for most temperate species. Their neutral lipid of E.superba was 29% of the total lipid and that of phospholipid was 71%. The majority of neutral lipid was triacylglycerols (31.6% of neutral lipids) while phosphatidyl choline (44% of phospholipid) was the most abundunt in phospholipids. The quantitative composition of the fatty acid in E. superba show consisting mostly of the saturated 16:0 (16.6% - 22.1%), along with the polyunsaturated 20:5(ω-3) (20.6% - 22.1%) and 22:6(ω-3) (14.9% -16.9%) acids.
O. Identification of useful genes from the Antarctic fish, Notothenia coriiceps
From the total RNA of the Antarctic fish's liver, cDNA was synthesized and 1111 clones of the cDNA library were sequenced. The sequences consist of 23.5% of the homologues of the functionally known genes, 8.0% of mitochondria and ribosome genes, and 68.5% of unknown genes. A few examples of the functionally known genes which have potential for commercial use include a stem-cell gene for blood production, Ferritin gene, interferon gamma-inducible protein gene, interleukin 10 homologue, and antifreeze polypeptide precursor gene. These genes of the fish could be utilized biotechnologically by production of proteins which would then be used as new materials in medicine.
P. Purification and characterization of psychrophyllic protease isolated from Antarctic bacteria and fish
Extracellular protease produced by Shewanella gelidimarina L93 was purified through ammonium sulfate precipitation, High-Q column chromatography, first gel permeation chromatography, BioScale Q2 ion exchange chromatography and second gel permeation chromatography to single band on SDS-PAGE, and basic properties of this enzyme were investigated. A protease purified from spleen of Notothenia fish was also investigated and and characterized.
Q. A study on the development of novel substances from Antarctic invertebrates
The structures of the two new metabolites of the suberitenone class from the Antarctic sponge Suberites sp., which might possess anti-chlolesterol traits were determined by combined spectral and chemical studies.