Seasonally breeding predators, which are limited in the. time available for provisioning young at a central location, and by the fasting abilities of the young, are likely to maximize energy delivery to the young by maximizing the rate of energy delivery averaged over the whole period of investment. Reduction in food availability or increased foraging costs will alter the optimal behavior of individuals. This study examined the behavioral adaptations of a diving predator, the Antarctic fur seal to increased foraging costs during lactation. One group of mothers (n = 5, treatment) was fitted with additional drag to increase the cost of transport in comparison with a control group (n = 8). At the scales of the individual dives, the treatment group made more shorter, shallower (
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Abstract:
Based on historic data as provided by the World Ocean Atlas 1994, the general climatic background for temperature, salinity and silicate is given for the area between the Fa1kland (Malvinas) Islands and the Antarctic Peninsula Region. A data set sampled during December 1996 in the Elephant Island Plateau Region by RV POLARSTERN, is compared to the climatic background data, and to more recent data as collected by German research vessels in this region. By means of a new interactive software water mass boundaries are outlined which reveal the approximate location of the Weddell-Scotia Confluence. Vertical distribution of oceanographic parameters temperature, salinity and density is discussed. Geopotential anomaly charts, referenced to 0/300 dbar reveal the general flow as given by the geostrophic part of the circulation. Compared to krill abundance data, the thermal and the dynamic fields indicate some correlation in the distribution of biotic, and abiotic parameters. Analysis of time series data at a station site to the north of Elephant Island, point at slow seasonal oscillations of the water mass boundary between the Weddell Sea waters and the Southeast Pacific Surface waters, the Weddell-Scotia Confluence.
The paper reiterates a recommendation as given in a previous SC-CAMLR paper by the same author, to do a co-operative analysis of data sampled throughout the years in the Elephant Island Plateau Region. With the new modem software as described in this paper, handling of large data bases becomes very easy.
