• Ocean and Polar Research
• /
• v.25 no.4
• /
• pp.633-644
• /
• 2003

The distribution and abundance of Antarctic krill (Euphausia superba), particularly in the South Atlantic, has traditionally been viewed as primarily determined by the flow of the Antarctic Circumpolar Current. Krill are viewed as being particles on a conveyor belt that carries them around the Antarctic continent resulting in a single circumpolar population. The evidence to support this viewpoint is largely circumstantial and there is very little direct evidence available of krill being moved by the currents-krill flux. There is also considerable biological and physical evidence which suggests that other factors may play a dominant role in the life history and distribution of krill. This review examines the evidence fur krill flux and also examines evidence that does not accord with this theory. The management implications of assuming krill flux are outlined and some lines for future research are suggested.

• Ocean and Polar Research
• /
• v.30 no.4
• /
• pp.467-472
• /
• 2008

Antarctic krill has a strong proteolytic enzyme system, which comes from a combination of several proteases. This powerful activity can be easily detected by krill's superior post mortem autolysis. Mammalian skin consists of epidermis and dermal connective tissue, and functions as a barrier against threatening environments. A clot in a wound site of the skin should be removed for successful skin regeneration. Epithelial cells secrete proteases to dissolve the clot. In previous studies Antarctic krill proteases were purified and characterized. The proteolytic enzymes from Antarctic krill showed higher activity than mammalian enzymes. It has been suggested that these krill clean up the necrotic skin wound to induce a natural healing ability. The enzymes exhibited additional possibilities for several other biomedical applications, including dental plaque controlling agent and healing agent for corneal alkali burn. Considering that these versatile activities come from a mixture of several enzymes, discovering other proteolytic enzymes could be another feasible way to enhance the activity if they can be used together with krill enzymes. Molecular cloning of the krill proteases should be carried out to study and develop the applications. This review introduces possible roles of the unique Antarctic krill proteases, with basic information and suggestion for the development of an application to skin regeneration.

• Ocean and Polar Research
• /
• v.23 no.4
• /
• pp.425-431
• /
• 2001

From an ecological point of view, the western part of the Atlantic sector is one of the most productive areas in the Southern Ocean. Antarctic krill (Euphausia superba) and krill-dependent predators such as fish, seals, and birds are abundant there, and most krill fisheries have operated in this area since 1970s. The hottest issues for the proper management of krill resources nowadays are to determine total biomass in this area, and to identify environmental forces controlling stock fluctuation. This paper reviews and collates information on ongoing oceanographic activities in the Antarctic Peninsula region concerning these issues. To delineate the status and function of Antarctic krill population in Antarctic marine ecosystems, multinational researches along the Antarctic Peninsula area have been developing recently. Four member states of CCAMLR (Japan, Russia, UK, and USA) had conducted acoustic surveys in January-February 2000 (socalled CCAMLR-2000 survey), and krill standing stock at 120 kHz was estimated to be 44.29 million metric tonnes in the western Atlantic sector of the Southern Ocean. On the other hand, the Southern Ocean GLOBEC (SO-GLOBEC) Programme has prepared a serial winter survey to examine the factors that govern krill survivorship and distribution in relation to shelf circulation processes. Ship-based surveys using ice-breakers are being conducted by three nations (Germany, UK, and USA) around the Marguerite Bay during the austral fall and winter 2001 and 2002. In addition to these two large-scale surveys, some CCAMLR members have carried out joint oceanographic surveys near the South Shetland Islands to detect ecosystem changes since 1994. Especially from December 1999 to February 2000, in conjunction with CCAMLR-2000 survey, four nations (Japan, Korea, Peru, and USA) conducted acoustic surveys to produce time-series information on krill distribution and biomass near the South Shetland areas. Though the aims of each program and the approach to solve the scientific questions were different each other, the results from each program fill the gaps between programs. Further cooperation and exchange in these activities could be beneficial to each program.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.50 no.6
• /
• pp.788-798
• /
• 2017

Antarctic krill Euphausia superba are important components of the Antarctic marine ecosystem both economically and ecologically; to manage this species effectively, their distribution and abundance must be understood. Using the Kwang Ja-Ho (3,012 tonnage), a commercial fishing vessel, we conducted acoustic surveys during April 13-24, 2016, to estimate the distribution and population size of krill around the South Shetland Islands of the Antarctic Continent, We used acoustic techniques based on the dB-difference, a method used mainly to classify of marine species. We found that Antarctic krill were present in numbers over 99% at six survey stations, with the exception of Station 3, where we only found Electrona carlsbergi. There was no difference in cell size due to frequency differences, but echo signals differed between species: 4.7-12.0 dB for Antarctic krill, and -4.1~0 dB for Electrona carlsbergi.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.21 no.5
• /
• pp.292-296
• /
• 1988

This review has dealt with the topics of biology of Antarctic krill, Euphausia superba. There are much of work on various aspects of the biological pattern of krill, in particular on reproduction, feeding and longevity. Nevertheless, the details of winter biology of krill still remained to be unclear. It is suggested that three kinds of energy Pathways, from inorganic or organic materials to krill, may occur in the Antarctic Ocean.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.21 no.5
• /
• pp.303-310
• /
• 1988

This review has dealt with the topics of biology of Antarctic krill, Euphausia superba. There are much of work on various aspects of the biological pattern of krill, in particular on reproduction, feeding and longevity. Nevertheless, the details of winter biology of krill still remained to be unclear. It is suggested that three kinds of energy Pathways, from inorganic or organic materials to krill, may occur in the Antarctic Ocean.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.58 no.4
• /
• pp.352-358
• /
• 2022

We explored the frequency response of krill target strength (TS) to understand the Antarctic krill (Euphausia superba) and ice krill (Euphausia crystallorophias) using the stochastic distorted-wave Born approximation (SDWBA) model. The results showed that the distribution of orientation and the fatness factor could significantly impact on the frequency response of TS. Krill TS is clearly depended on acoustic properties, which could affect to estimate the biomass of two krill species. The results provide insight into the importance of understanding TS variation to estimate the Antarctic krill and ice krill biomass, and their ecology related to the environmental features in the Southern Ocean.

• Fisheries and Aquatic Sciences
• /
• v.10 no.4
• /
• pp.215-219
• /
• 2007

Long-tenn variation in krill (Euphausia superba) and salp (mainly Salpa thompsoni) stocks was compared to environmental changes in the Atlantic and Indian sectors of the Antarctic. Environmental conditions examined were air temperature, water temperature, salinity, and sea-ice extent from 1926 to 1938 and from 1982 to 2000. The long-term pattern of krill was opposite to that of salp: krill stock decreased while salp stock increased concurrently. Krill stock was about three-fold higher from 1926 to 1938 than from 1982 to 2000, but salp was about four -fold lower in 1926-1938 than in 1982-2000. A wanning trend was observed in the environmental data, and the long-term variation in krill and salp stocks was affected by this trend.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.51 no.4
• /
• pp.435-443
• /
• 2018

The Antarctic krill Euphausia superba is important commercially and ecologically as a basic component of the Antarctic Ocean ecosystem. To manage this resource, it is important to determine the distribution and standing of krill in the water layer. Acoustic methods can capture information about the entire water layer quickly. Acoustic surveys were conducted from March 3 to March 14, 2017, using the commercial fishing boat Sejong (7,765 tons). Acoustic systems with a frequency of 38 kHz and a 200 kHz commercial echo sounder (ES70, Simrad, Norway) were used and the acquired data were processed using post processing software. The density and standing of Antarctic krill were determined using the two-frequency difference method, using the characteristics of two frequencies. To compare the frequency difference of krill, the method using the frequency difference according to the krill length, recommended by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) and the values extracted according to the krill length at survey stations where only krill were collected during the study period, were compared. The frequency difference ranges were 3.96-5.91 dB and -3.0~13.8 dB, respectively.

• Fisheries and Aquatic Sciences
• /
• v.17 no.4
• /
• pp.403-408
• /
• 2014

Antarctic krill Euphausia superba is an excellent potential source of food protein. We used enzymatic hydrolysate of Antarctic krill and 10 other precursors to seek the optimum krill reaction flavor and apply to ramen sauce. Krill concentrate and powder were compared by sensory evaluation. The krill powder performed better preference, and was added to ramen sauce, which itself performed better than a commercial shrimp flavored sauce. In total, 47 and 39 volatile compounds were identified from krill concentrate and powder, respectively. Both products contained many aldehydes and sulfur-containing compounds. The whisky flavor of aldehydes lowered the shrimp flavor of the krill concentrate. Sulfur-containing compounds were found in krill powder, confirming the results from sensory evaluation.