FS POLARSTERN ANT XX1/4

WEDDELL SEA VOYAGE 27/03 to 06/05 2004

Shannon and Kelly, the two whale observers from the International Whaling Commission continue to scan the horizon and the vast expanse of Southern Ocean for that ever-elusive blow. The initiative of collaboration with other Antarctic research programs aims to examine variability in baleen whale distribution and movements in southern waters in relation to their prey, Antarctic krill and sea ice concentrations. At this time of the year they would expect to see a number of whale species migrating between the continental waters and warmer breeding waters, especially humpback whales. They would also expect to see some species in the sea ice areas, including minke and killer whales. On transit between Cape Town and the cruise survey area, only one whale sighting was made, but this was likely due to reduced effort due to weather and low sightability conditions. The survey area (between 64 and 70ºS and 0 to 4ºW) proved to be a different story with 16 sightings of 22 whales including humpback and minke whales, a single sperm whale and some unidentified species. Four sightings of 12 individual humpback whales were made on the 25^th of April in an extended survey leg north of the 4^th transect. These whales were all traveling north, an indication of the ice cover extending and the whales starting on their northward migration.

One exceptional sighting occurred on the 27^th of April with four humpback whales choosing to spend over four hours with the vessel. A single blow was initially seen on the port side of the vessel at 11:00 UTC and was immediately recognized as a humpback whale. As it approached closer more blows were sighted and the group was identified as five individuals. There were also approximately 150 chinstrap penguins swimming around the vessel and as the whales approached closer to the vessel, they started chasing each other, possibly for play or seeking the same food source. At one point, the group of five whales split and two individuals swam around the bow to the starboard side while the other three remained on the port side. During this time, one of the whales from the port side disappeared out towards the horizon where another group of humpback whales was present. The remaining four then continued to surface around the vessel for the next four hours, blowing, snorting, pectoral fin slapping, spyhopping and even breaching, giving everyone on board a spectacular show, although it's possible that the whales were just as interested in us as we were in them.

Although the overall total of sightings during the voyage is not high at 26 observations of 50 individuals, it is reasonable for this area at this time of year and the patchiness expected in whale distribution.

Submitted by Shannon McKay

April 29, 2004

FS POLARSTERN - ANT XXI/4

CETACEANS AND SEA ICE - Lazarev Sea 2004

Shannon McKay and Kelly Asmus, both from the Whale Ecology Group Southern Ocean at Deakin University in Warrnambool, Australia, are conducting visual observations of cetaceans and sea ice aboard the Polarstern, the prestigious vessel of the Alfred Wegener Institute in Bremerhaven, Germany.

Departing from Cape Town, South Africa on the 27^th of March 2004, they are currently southbound towards the German base, Neumayer, in the Lazarev Sea, part of the greater Weddell Sea gyre system. The main research focus this season is on the biology (over-wintering) of Antarctic krill (Euphausia superba) between the Greenwich meridian to 20ºE and 62ºS to 70ºS. A range of other scientific disciplines will be at work, including biological and oceanographic surveys from a number of international programs.

Shannon and Kelly will be actively searching for whales, dolphins, seals and seabirds in all suitable weather conditions as well as obtaining sea ice concentration data, essential for determining what effects the patterns in concentration have on the distribution and densities of cetaceans in Antarctic waters.

Submitted by Shannon McKay