Natural age-dependent mortality rates of Antarctic krill Euphausia superba Dana in the Indian sector of the Southern Ocean

Polar Biology ◽  
1995 ◽  
Vol 15 (1) ◽  
Author(s):  
E.A. Pakhomov
Keyword(s):  
Southern Ocean ◽  
Antarctic Krill ◽  
Euphausia Superba ◽  
Mortality Rates ◽  
Age Dependent ◽  
Indian Sector ◽  
Antarctic Krill Euphausia Superba ◽  
Dependent Mortality

Demography and life cycle of Antarctic krill, Euphausia superba, in the Indian sector of the Southern Ocean: long-term comparison between coastal and open-ocean regions

2000 ◽  
Vol 57 (S3) ◽  
pp. 68-90 ◽  
Author(s):  
E A Pakhomov
Keyword(s):  
Southern Ocean ◽  
Life Span ◽  
Antarctic Krill ◽  
Age Groups ◽  
Substantial Reduction ◽  
Euphausia Superba ◽  
Age Composition ◽  
Indian Sector ◽  
Antarctic Krill Euphausia Superba

Size/age composition and reproductive status of Antarctic krill, Euphausia superba, in the central part of the Indian sector of the Southern Ocean, e.g., the Cooperation Sea (Prydz Bay region) and the Cosmonaut Sea, during austral summers 1977-1990 were summarized to estimate growth rates, longevity, reproduction, recruitment, life span, and mortality rates. The life span of Antarctic krill exceeds 5 years in both the Cosmonaut and Cooperation seas. The age composition of the southern and northern groupings differs markedly, with substantial reduction in numbers of early age groups in the northern grouping. Long-term observations of spawning success, recruitment, and age composition suggest that a self-sustained grouping of krill persists in the Cooperation Sea south of the Antarctic Divergence. However, periodic gene flow via recruits from surrounding regions most probably accounts for the lack of spatial genetic differences between the Cooperation Sea and adjacent areas, thus preventing the establishment of an isolated subpopulation in the region investigated. The major factor responsible for the substantial interannual variability in krill dynamics appears to be macroscale oceanographic and atmospheric circulations, which determine a level of environmental isolation of the Cooperation Sea from adjacent waters.

Behavioural sensitivity of a key Southern Ocean species (Antarctic krill, Euphausia superba) to p,p′-DDE exposure

2012 ◽  
Vol 75 ◽  
pp. 163-170 ◽  
Author(s):  
Anita H. Poulsen ◽  
So Kawaguchi ◽  
Catherine K. King ◽  
Robert A. King ◽  
Susan M. Bengtson Nash
Keyword(s):  
Southern Ocean ◽  
Antarctic Krill ◽  
Euphausia Superba ◽  
Antarctic Krill Euphausia Superba

scholarly journals Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013

2014 ◽  
Vol 71 (9) ◽  
pp. 2578-2588 ◽  
Author(s):  
Sophie Fielding ◽  
Jonathan L. Watkins ◽  
Philip N. Trathan ◽  
Peter Enderlein ◽  
Claire M. Waluda ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Interannual Variability ◽  
Antarctic Krill ◽  
Southern Oscillation ◽  
Euphausia Superba ◽  
Target Strength ◽  
South Georgia ◽  
Key Species ◽  
The Mean ◽  
Antarctic Krill Euphausia Superba

Abstract Antarctic krill (Euphausia superba) are a key species in Southern Ocean ecosystems, maintaining very large numbers of predators, and fluctuations in their abundance can affect the overall structure and functioning of the ecosystems. The interannual variability in the abundance and biomass of krill was examined using a 17-year time-series of acoustic observations undertaken in the Western Core Box (WCB) survey area to the northwest of South Georgia, Southern Ocean. Krill targets were identified in acoustic data using a multifrequency identification window and converted to krill density using the Stochastic Distorted-Wave Born Approximation target strength model. Krill density ranged over several orders of magnitude (0–10 000 g m−2) and its distribution was highly skewed with many zero observations. Within each survey, the mean krill density was significantly correlated with the top 7% of the maximum krill densities observed. Hence, only the densest krill swarms detected in any one year drove the mean krill density estimates for the WCB in that year. WCB krill density (µ, mean density for the area) showed several years (1997/1998, 2001–2003, 2005–2007) of high values (µ > 30 g m−2) interspersed with years (1999/2000, 2004, 2009/2010) of low density (µ < 30 g m−2). This pattern showed three different periods, with fluctuations every 4–5 years. Cross correlation analyses of variability in krill density with current and lagged indices of ocean (sea surface temperature, SST and El Niño/Southern Oscillation) and atmospheric variability (Southern Annular Mode) found the highest correlation between krill density and winter SST (August SST) from the preceding year. A quadratic regression (r2 = 0.42, p < 0.05) provides a potentially valuable index for forecasting change in this ecosystem.

scholarly journals Facing Southern Ocean warming: Temperature effects on whole animal performance of Antarctic krill (Euphausia superba)

Zoology ◽  
2021 ◽  
Vol 146 ◽  
pp. 125910 ◽  
Author(s):  
Katharina Michael ◽  
Lavinia A. Suberg ◽  
Wiebke Wessels ◽  
So Kawaguchi ◽  
Bettina Meyer
Keyword(s):  
Southern Ocean ◽  
Temperature Effects ◽  
Antarctic Krill ◽  
Euphausia Superba ◽  
Ocean Warming ◽  
Animal Performance ◽  
Antarctic Krill Euphausia Superba

scholarly journals Oxidative stress, metabolic activity and mercury concentrations in Antarctic krill Euphausia superba and myctophid fish of the Southern Ocean

2021 ◽  
Vol 166 ◽  
pp. 112178
Author(s):  
José Seco ◽  
Rosa Freitas ◽  
José C. Xavier ◽  
Paco Bustamante ◽  
João P. Coelho ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Southern Ocean ◽  
Metabolic Activity ◽  
Antarctic Krill ◽  
Euphausia Superba ◽  
Myctophid Fish ◽  
Antarctic Krill Euphausia Superba
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