Distribution and abundance of Antarctic krill (Euphausia superba) along the Antarctic Peninsula


Contact
Gerd.Rohardt [ at ] awi.de

Abstract

Net-based data on the abundance, distribution, and demographic patterns of Antarctic krill are quantified from a contemporaneous two ship survey of the Antarctic Peninsula during austral summer 2011. Two survey areas were sampled focussed on Marguerite Bay in the south, and the tip of the Antarctic Peninsula in the north. Data from 177 stations showed that the highest concentrations of krill were found in the southern sampling area. Differences between areas were associated with a few large catches of one year old krill found in anomalously warm and productive waters in Marguerite Bay, and small krill catches in the less-productive, offshore waters in the north. Estimated krill density across the survey area was 3.4krillm-2, and was low compared to the long-term average of 45krillm-2 for the Elephant Island area. Overall recruitment between the two survey regions was similar, but per capita recruitment was about 60% lower than historical mean recruitment levels measured at Elephant Island since the late 1970s. Demographic patterns showed small krill concentrated near the coast, and large krill concentrated offshore on the shelf and slope all along the survey area. The offshore distribution of adult krill was delineated by the warm (~1°C), low salinity (33.8) water at 30m, suggesting that most krill were present shoreward of the southern boundary of Antarctic Circumpolar Current Front. Distributions of larvae indicated that three hotspot areas were important for the production of krill: slope areas outside Marguerite Bay and north of the South Shetland Islands, and near the coast around Antarctic Sound. Successful spawning, as inferred from larval abundance, was roughly coincident with the shelf break and not with inshore waters. Given the rapid changes in climate along the Antarctic Peninsula and the lower per capita recruitment observed in recent years, studies comparing and contrasting production, growth, and recruitment across the Peninsula will be critical to better understand how climate change will impact krill populations and their dependent predators in the Scotia Sea. © 2013 Elsevier Ltd.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Research Networks
IPY
Publication Status
Published
Eprint ID
32877
DOI https://www.doi.org/10.1016/j.dsr.2013.02.005

Cite as
Siegel, V. , Reiss, C. S. , Dietrich, K. S. , Haraldsson, M. and Rohardt, G. (2013): Distribution and abundance of Antarctic krill (Euphausia superba) along the Antarctic Peninsula , Deep Sea Research Part I: Oceanographic Research Papers, 77 , pp. 63-74 . doi: https://www.doi.org/10.1016/j.dsr.2013.02.005


Share


Citation

Research Platforms

Campaigns
ANT > XXVII > 2


Actions
Edit Item Edit Item