Winter distribution and size structure of Antarctic krill Euphausia superba populations in-shore along the West Antarctic Peninsula

Cleary, AC; Durbin, EG; Casas, MC; Zhou, M. 2016 Winter distribution and size structure of Antarctic krill Euphausia superba populations in-shore along the West Antarctic Peninsula. Marine Ecology Progress Series, 552. 115-129. 10.3354/meps11772

[img]
Preview
Text
m552p115.pdf - Published Version
Available under License Creative Commons Attribution.

Download (976kB) | Preview
Official URL: http://dx.doi.org/10.3354/meps11772

Abstract/Summary

Antarctic krill Euphausia superba are a key component of food webs in the maritime West Antarctic Peninsula, and their life history is tied to the seasonal cycles of sea ice and primary production in the region. Previous work has shown a general in-shore migration of krill in winter in this region; however, the very near-shore has not often been sampled as part of these surveys. We investigated distribution, abundance, and size structure of krill in 3 fjordic bays along the peninsula, and in the adjacent Gerlache Strait area using vertically stratified MOCNESS net tows and ADCP acoustic biomass estimates. Krill abundance was high within bays, with net estimated densities exceeding 60 krill m-3, while acoustic estimates were an order of magnitude higher. Krill within bays were larger than krill in the Gerlache Strait. Within bays, krill aggregations were observed near the seafloor during the day with aggregations extending to the sediment interface, and exhibited diel vertical migration higher into the water column at night. We suggest these high winter krill abundances within fjords are indicative of an active seasonal migration by krill in the peninsula region. Potential drivers for such a migration include reduced advective losses and costs, and availability of sediment food resources within fjords. Seasonally near-shore krill may also affect stock and recruitment assessments and may have implications for managing the krill fishery in this area.

Item Type: Publication - Article
Additional Keywords: Euphausiid · Abundance · Diel vertical migration · DVM · WAP · Fjord
Divisions: Marine Biological Association of the UK > Other (MBA)
Depositing User: Barbara Bultmann
Date made live: 03 Oct 2016 15:13
Last Modified: 06 Jun 2017 16:17
URI: http://plymsea.ac.uk/id/eprint/7226

Actions (login required)

View Item View Item