Next to tick off the bucket list, the world’s top ocean predator – the killer whales. Having never seen these before, I travelled to Antarctica with very high expectations, knowing estimates of these animals in Antarctic waters to be somewhere in the region of 70-80,000.
On just our second day in Antarctic waters, we kept the schedule free and were instructed to get outside and look for big black and white animals. Within a few hours in the Weddell Sea, we were surrounded by several groups of Type B killer whales.
We were lucky to have killer whale scientists on board the ship and within a few minutes of the sighting, they were launching the Zodiac in order to get closer to these animals and collect their data.
The scientists, from the NOAA, were using drones to fly above the animals and take pictures, which give them accurate information about the size and health of the whales. This new technique of observation also allows them to see what the whales are getting up to beneath the water, observe new behaviours and also make more accurate counts of pods.
As you can see, the killer whales in the pictures have very brown colouring where stereotypical killer whales would be white. This is a result of the cold water temperature – the brown is actually diatoms (a type of single cell algae) living on the surface of the whales. Normally, killer whales would have a good blood flow to the skin, which would prevent this diatomaceous growth. However in cold waters, this would involve the loss of too much energy.
If you look closely at the images, you can see round circular scarring on the whales, these are from cookie cutter sharks, which are only found in the tropics, a bit bewildering considering these killer whales are seen in Antarctic waters all year round.
Also, it was strange that the same individuals, photographed on different days, often had high diatom growth followed by clean skin. The NOAA team previously put tags on these whales which showed that they make very rapid journeys to the tropics to get manicures before swimming all the way back south!
Next up were the Type A killer whales, which are much more like the killer whales seen in the northern hemisphere. These are larger and tend to be more black and white than the Bs and they feed on Minke whales and elephant seals.
Using a combination of the saddle patches, markings and fin shape it is possible to identify individuals using photos. We were lucky to see the same group of Type A killer whales near Ciervo Cove on both expeditions, as confirmed by photos.
There are two types of B killer whales. ‘Little’ Bs, which tend to dive deep and feed predominantly on fish, supplemented by the odd penguin! And ‘big’ Bs, which opt for washing seals (especially Weddells) off the ice to feed. Having seen the little Bs several times already, we pushed further into the Weddell sea into the thicker ice and, as we hoped for, we found a group of big Bs, giving us the “full house” for the area we had been.
Since conditions were calm, the ever eager scientists launched the Ribs and returned with some alarming images of the whales. The whales were not in particularly good health, with much of the skeletal features of the animals visible in the pictures. Possibly, this was a result of lower prey scarcity, with very few Weddell seals observed on the ice. However, at this stage the scientists could only hypothesise.
We also had a team from CBS on board who did a piece on these encounters, which you can see by following this link below…
Fortunately, the trip did not end on this low since sightings continued wherever we went. My season culminated with one of my favourite nature experiences ever, as a group of 40 little B’s passed straight across the bow of the vessel in the crystal clear Antarctic waters.
Clip showing footage from a couple of the Killer Whale encounters