Antarctic Science
- Antarctic Science / Volume 14 / Issue 02 / June 2002, pp 162-170
- Copyright © Antarctic Science Ltd 2002
- DOI: http://dx.doi.org/10.1017/S095410200200072X (About DOI), Published online: 27 April 2004
Demography of krill in the Elephant Island area during summer 2001 and its significance for stock recruitment
AbstractA net sampling survey was carried out for krill in a standard station grid around Elephant Island during 27 January to 4 February 2001. In comparison with recent years the station grid was extended south, where a large proportion of small size classes, one-year-old juvenile krill was found. Results show a spatial separation of the juvenile krill and the spawning stock, Krill density was significantly higher than during the past years (229 krill 1000 m−3 or 13.0 g m−2). The proportional recruitment index for the entire survey area for the 1999/2000 year class was R1 = 0.573, which is among the highest values recorded during the past 20 years. The maturation index (based on the proportion of gravid stages) was G = 0.99, indicating an early initiation of the spawning season. The results indicate a turning point after a succession of years with poor recruitment success and low stock biomass. This is thought to be the first step for a successful spawning event and a later potential recruitment success of the 2000/01 year-class. The spatial extent of the station grid is discussed in the light of a representative coverage of the stock and the estimated recruitment index. (Received September 4 2001)(Accepted January 2 2002) Key Words: abundance; distribution; Euphausia superba; monitoring; South Shetland Islands; zooplankton. Correspondence: c1 siegel.ish@bfa-fisch.de |
