Tag Archives: Whales Tasmania

Super-Groups of Humpback Whales & Bubble-net Feeding

New paper published about the formation of ‘super-groups’ of Humpback Whales and bubble-net feeding in East Australian waters

Large groups of Humpback Whales came together to feed along the south-east coast of Australia, including here in Tasmania.

The last Humpback Whale migration south, between September and November 2020, has really been something special. Not only in Tasmania, but all along the south-east coast of Australia.

We’re excited that we had the opportunity to contribute photographic evidence of the formation of ‘super-groups’ of Humpback Whales as well as ‘bubble-net feeding’ behaviour to a scientific paper that got published two days ago. The paper by Vanessa Pirotta, Kylie Owen, David Donnelly, Madeleine J. Brasier, Robert Harcourt is titled: First evidence of bubble-net feeding and the formation of ‘super-groups’ by the east Australian population of Humpback Whales during their southward migration. If you are interested, you can access the full paper here. It’s definitely worth a read! 🙂

Super-groups of Humpback Whales feeding in Tasmanian waters.
Humpback Whales feeding in close proximity of each other.

First recorded evidence of bubble-net feeding by Humpback Whales off Tasmania and East Australia

Dr. Maddie Brasier, who is one of the co-authors of the paper and also our ‘in-house’ marine biologist has put together why this publication is another important step towards ensuring the conservation of Humpback Whales in Tasmanian and east Australian waters, so read on:

Pirotta’s paper includes three accounts of bubble-net feeding within Tasmanian waters, all three of which were recorded by Wild Ocean Tasmania. 

What is bubble-net feeding?

Bubble-net feeding is when Humpback Whales expel air underwater to create a ring of bubbles around their prey. They then lunge towards the surface inside that ring of bubbles, engulfing a massive mouthful of food. Bubble-net-feeding can be performed by single individuals or multiple animals lunging into the same bubble-net. All observations of bubble-net feeding by Wild Ocean Tasmania in the 2020 summer season involved single individuals. 

To create the bubble-nets, Humpback Whales turn tightly whilst expelling air. Humpbacks can do this, because their huge flippers are edged with tubercules. These fist-sized bumps contain one hair follicle that is connected to a series of sensitive nerves. The tubercules increase lift and decrease drag as they swim through the water. These physical features make them incredibly hydrodynamic and more agile than other whale species. 

Prior to the observations recorded in Pirotta et al. bubble-net feeding in the Southern Hemisphere had only been formally documented in Antarctica. These new observations are really exciting, and we feel incredibly lucky to have documented these events in Tasmanian waters. 

A single Humpback Whale bubble-net feeding in Tasmania – Screenshot of drone footage

Why are these observations important?

It was believed that Humpback Whales followed the “feast and famine” rule whilst migrating, feeding only in their polar feeding grounds, then fasting on migration and in their sub-tropical calving grounds. We now know this is not the case, with many records and sightings of Humpback Whales feeding during their migration in previous years, including many Wild Ocean Tasmania sightings here in Tasmanian waters.

Feeding during migration, also referred to as supplementary feeding, suggests that there is a need for Humpback Whales to supplement their energy supply outside of their summer feeding in Antarctica. Supplementary feeding may become increasingly important as our Oceans change. Flexibility in feeding practices is important for a species’ ability to adapt to changing Ocean conditions such as increased temperatures and nutrient availability. As temperature and nutrients influence the Ocean productivity, this can ultimately affect the distribution and abundance of prey species for larger marine species like Humpback Whales.

It is also possible that specialised behaviours such as bubble-net feeding may be increasingly observed as the East Australian Humpback Whale population continues to recover from industrial whaling. Such behaviours may have been present prior to over-exploitation, but are only now reappearing and being observed.

Several Humpback Whales feeding together

What does this mean for Tasmanian waters?

At present we do not fully understand the importance of Tasmania as a feeding ground to Humpback Whales and other cetacean species. However, by investigating how environmental variation and population dynamics can influence the feeding of Humpback Whales in Tasmanian waters, it will help us predict how future Ocean change may influence whale populations. This could also provide evidence for more effective management to reduce threats to Whales during known feeding periods. 

The observations in Pirotta et al. were primarily from citizen scientists and highlight the importance of observing and recording our wildlife. In Tasmania you can contribute your whale sightings to the Tasmania Fluke Project (email your photos to madeleine.brasier@utas.edu.au or to Wild Ocean Tasmania), or report your sighting to the DPIPWE Marine Conservation Programme. So get out there and tell us what you see!

Christmas Awesomeness

The Ocean has come alive for Christmas

A whale, dolphins and seabirds feeding in the Tasman Sea, Tasman Peninsula.
A Humpback Whale lunge-feeding in amongst Dolphins and Seabirds.

Following a cold and stormy start of summer, the last two weeks of December have been amazing in terms of weather and wildlife activity. The Ocean has come alive! Big schools of fish have attracted predators, Dolphins, Seals and even Humpback Whales for a feast.

A Feeding Frenzy with Australian Fur Seals proposing and a whale rounding up bait fish.
A Feeding Frenzy with Australian Fur Seals porpoising and a Humpback Whale rounding up the bait fish.

It’s the very end of the Humpback Whale migration here in Tasmania. The Humpback Whales spend our winter months up north in warmer waters to breed and give birth. We usually get to see them swim past our coastline on their way south towards their main feeding grounds in Antarctic waters between the end of September and mid December. The incredible amount of food available over the last couple of weeks has been a well deserved treat for the whales that have already swam about 2500km.

Bottlenose Dolphin doing a backflip.
Happy Dolphins putting on a show for us after a good feed.

Some days have literally been Nat Geo style with hundreds of Bottlenose Dolphins putting on a show for us and lots of sea birds cashing in on some left overs. Check out this short video on Instagram filmed with our drone to see how the whales, dolphins and seals were working together to round up the fish.

https://www.instagram.com/p/B6fWbrahrFv/?utm_source=ig_web_copy_link

Sydney to Hobart Yacht Race

Most Watersport and Ocean enthusiasts have followed the Sydney to Hobart Yacht Race. It’s an annual event hosted by the Cruising Yacht Club of Australia, starting in Sydney, New South Wales on Boxing Day and finishing in Hobart, Tasmania. The race distance is approximately 630 nautical miles (1,170 km). It is considered to be one of the most difficult yacht races in the world, due to the ferocious weather conditions that can occur on this route.

The crew of one of the Sydney to Hobart yachts sitting on the side of the boat, heading down towards Tasman Island.
The crew on ‘Celestial’ on their way down towards Tasman Island, which is the turning point to then head up into the Hobart port.

This year, the weather has been relatively calm for the yacht race, which allowed us to head out to sea and greet some of our friends who took part in the race on their way south towards Tasman Island, from where they would turn and head up into Hobart. Not only did we get to wave to our friends onboard the racing yacht, we were also greeted by some more inquisitive Humpback Whales. 🙂

A lucky snap of a Humpback Whale that popped up in-between our vessel and ‘Celestial’, one of the Sydney to Hobart racing yachts.

Albatrosses during our bird charter

Another annual event for us has been a bird charter that we provide for a private group at the end of the year. We’ve encountered lots of different species of seabirds, including these special Albatrosses.

A Wandering Albatross that we encountered on our bird charter.
A Wandering Albatross.

Wandering Albatrosses are the largest of the Albatrosses with the greatest wingspan of any living bird, measuring almost 3.5 meters. They spend most of their life in flight, landing only to breed and feed. Wandering Albatrosses can travel vast distances, with one banded bird recorded that travelled 6000 km in twelve days! Unfortunately, these amazing Ocean roaming birds are classed as endangered in Tasmania, which makes it even more special to see them on our bird charter!

A beautiful Campbell Albatross in flight.
The beautiful Campbell Albatross.

We’ve also encountered this beautiful Campbell Albatross. On first sight, they look very similar to the Black-browed Albatrosses, with the white head, the pretty black brow, a bright yellow beak and strong leading edge on the underwing. The main distinguishing feature is their honey coloured iris (instead of the dark brown iris of the Black-browed Albatross). They breed only on the sub-Antarctic Campbell Island which is part of New Zealand.

Welcome 2020!

With so much activity along our stretch of coastline recently, we can only hope that this will continue in the new year. It will be interesting to see how long the Humpback Whales will stay in the area for.

Snorkelling with seals in Tasmania
Snorkelling with the playful puppies of the Sea.

Late summer and autumn is also the best time of the year to snorkel with the Seals in Tasmania. After the females have given birth and the breeding season is over, the animals are more relaxed and therefore even more interested in playing with us. 🙂

If you love nature and wildlife, join us on one of our tours!