Report #1: Hobart, Australia, to Mawson, Antarctica. (Map 1)

After last minute panic that the whale acoustics team sonobuoys would not arrive before scheduled departure, we eventually left Hobart, Tasmania, in the late afternoon. Last light was spent sailing down the Derwent River towards the Southern Ocean – home for the next few months.

The first few days would be spent steaming to the Australian Antarctic base, Mawson, off which we are to conduct a fine-scale krill survey, as per what we attempted 2 years ago. Unfortunately, during the previous attempt (known as the KACTAS voyage of year 2000/1) we were requested to abort our research half-way through to assist another ship stuck in ice for the past few weeks. The importance of this research to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) led the Australian government to set aside money to re-attempt these studies.

No sooner had we left the protection of Tasmania than the Southern Ocean let us know who was ‘boss’. The Roaring Forties & Furious Fifties lived up to their names with the ship shuddering under the strain of severe swells (over 4m in height) and winds of over 40 knots. Not too many folks were up & about during those first few days while getting their ‘sea-legs’! The terrible weather continued for two days before it cleared slightly – well enough to log a sighting of fin whales. The next morning it was back to serious rolling again. Eventually we ‘ducked south’ between two low-pressure systems and started getting ‘workable’ weather on day 7. This resulted in sightings of our first minke whales, plus a small group of long-finned pilot whales – not much, but considering we were in the middle of ‘nowhere’ (i.e. no topographical or oceanographic features nearby that would initiate a food-web and provide abundant food for predators) they kept us ‘happy’. The following morning we awoke to find that we were at last amongst some ice bergs and ‘bergy bits’ (chunks of berg that have fallen off and drift in the sea) and the light snowfall certainly added to the feeling that ‘we’d arrived’! A distant minke whale and a group of 8 killer whales right next to the ship were the only sightings for the day, but good to be back Down South!

A trial run with CTDs occurred during the night, which suits us fine as the ship is stationary while they lower the device to the seabed & we can’t conduct our whale survey at ship speeds less than 10 knots (international standard survey techniques). CTD is the acronym for Conductivity, Temperature and Depth recorder.  This device gets lowered from a special door in the side of the ship and goes all the way to the bottom recording water data.  There is also an ADCP (Acoustic Doppler Current Profiler) attached to the CTD which allows information to be gathered on the current dynamics through measuring the time lapse between echoes from sound pulses emitted into the water column.  Then, en route back up from the seabed, electronic messages are sent to the CTD rosette to collect water samples (in special bottles on the instrument) from whichever depth you require the sample.  This water is used in a multitude of projects on board, from nutrient and oxygen contents, through to plankton studies.  

On the whale side, the voyage down here was pretty Spartan (see Map 1), with three of four sightings a day (one of which, a group of long-finned pilot whales led to the first sound recordings by the whale acoustics team). However, Tuesday the 14^th, was an exceptional day:

“After a good night's sleep due to still waters, I was rudely awoken on Tuesday morning by a call from the bridge: we were in pack-ice & my colleagues who had never seen pack-ice wanted to know what to do.  So, up I got and joined them on the bridge to explain ice-types & how to search in this habitat. Added to the ice everywhere was a very light snowfall - definitely felt you were in Antarctica!  From there the sightings started pouring in.  In addition to recording whales and their habitat (ice-types), we're also recording seals. It got really busy as crabeater seals were resting on ice floes everywhere as we crunched past.  Antarctic minke whale recordings were trickling in at a few an hour, but enough to keep the interest up.  Everyone was on the bridge with their cameras and the place was abuzz with excitement, especially from the 'first timers'.  As the day progressed the skies cleared to a beautiful 'balmy day' (0.5 degrees).  It took only 2-3 hours to get out of the pack-ice which had been blown offshore by the katabatic winds (strong winds coming down from the Antarctic plateau).  No sooner did we reach more 'open' water than the whale sightings came pouring in: by the end of the day we'd racked up just under 40 sightings ranging in species from fin whales (4 sightings: 6 whales total), humpback whales (9:16) and minke whales (16:23), to sperm (1:1), pilot (1:50) and killer whales (1:40), plus 6 sightings of 7 unidentified whales. Wow, what a day – almost more than we could handle!  Decided to end the day at 9pm as we were exhausted, even though there were sperm whales and other whales still visible from the bridge.  It took another 2 hours before all the data was completed and transferred to Excel spreadsheets - so a VERY long day.  The clear skies allowed us to see the green flash at sunset (11:30pm), then a cup of warm tea and to bed in an exhausted collapse”.

MAP 1.

The following day (16 January: date of arrival at the ‘krill box’) we had only three whale sightings – what a difference from one day to the next! It will be interesting to correlate this difference to differences in environmental conditions.

In conclusion, 59 sightings of cetaceans were made during the 11.5 days of transit from Hobart to the Mawson krill box. These included 16 categories of cetaceans, totaling 69 mysticetes, 96 odontocetes and 5 undetermined cetaceans (Table 1). All sightings are plotted along the transect line (Map 1); however, to simplify the plots all sightings are lumped to the most likely species (e.g. undetermined species of minke, ‘like’ minke whale and Antarctic minke whale are combined and labeled as ‘minke whale’).

(You can catch up on daily details at http://www.aad.gov.au through the “Southbound” section, or maybe they even have a special page for us – V4 KAOS [Krill Acoustics & Oceanography Study])

Table 1: Categories of whale sightings made on transect between Hobart & Mawson.

Whale species sighted	Common name	Total number of sightings: Total number of animals seen
Balaenoptera physalus	Fin whale	4:6
Like fin whale	Like fin whale	1:2
Physeter macrocephalus	Sperm whale	2:2
Like sperm whale	Like sperm whale	-
Orcinus orca	Killer whale	3:52
Balaenoptera borealis	Sei whale	-
Undetermined species of minke	Undetermined species of minke	2:4
Like minke whale	Like minke whale	2:3
Balaenoptera bonaerensis	Antarctic minke whale	16:21
Megaptera novaeangliae	Humpback whale	13:23
Like humpback whale	Like humpback whale	3:4
Globicephala melas	Long-finned pilot whale	2:42
Unidentified cetacean	Unidentified cetacean	1:1
Unidentified whale	Unidentified whale	2:2
Unidentified small whale	Unidentified small whale	1:1
Unidentified large whale	Unidentified large whale	1:1
Unidentified baleen whale	Unidentified baleen whale	2:2
Unidentified small baleen whale	Unidentified small baleen whale	-
Unidentified large baleen whale	Unidentified large baleen whale	3:4