Humpback whale northward migration check in
The annual northward migration is here off the east coast of Australia and the humpback highway is in full swing. Already we have had large numbers of whales transiting along New South Wales waters. We’ve seen breaches and tail slaps galore and for a little variety, lots of dwarf minke whales with calves earlier on in the season which has been the highlight for many.
This time each year we see thousands of humpback whales moving north to Queensland where they’re on a mission to warmer waters. They have just spent the summer feeding in Antarctica and now it’s time to mingle, breed and for some whales, give birth. Speaking of having young, a female humpback whale is generally pregnant for 11-12 months and when their calf or baby is born, they can be almost as long as a small car.
The east coast humpback whale population is often referred to as a conservation success story. This population was once hunted to near extinction, but since whaling of humpback whales in southern waters ended in the early 1960s this population has been rebounding each year at around 10.9%, so now there is likely over 30,000 humpback whales.
While that’s great news for the whales and us as whale watchers, scientists and wildlife managers around the world work hard to manage whale interactions with human activities in the ocean. Well known examples include: entanglement in fishing gear, vessel strike with boats and ships, acoustic pollution produced by vessels and underwater construction, marine pollution such as ingestion of rubbish and climate change. Warming sea water means loss of sea ice in areas like Antarctica where Antarctic krill live. These small critters are the main food source for this growing humpback whale population.
Fortunately, in Australian waters, whales are protected as migratory species and we do our best to help ensure growing whale populations are best protected from some of these threats. For example, we have guidelines for how boats operate around whales and have response teams to help detangle whales caught in fishing nets. Scientists are also working on ways to prevent whale entanglement in fishing gear by testing acoustic devices placed on fishing gear to acoustically warn whales of their presence.
But you don’t need to be a scientist to make a difference for whales. For example, you can do your part for the marine environment by using reusable shopping bags, disposing of rubbish appropriately, not releasing balloons into the sky and saying no to straws.
The humpback whale northward migration will continue all the way up until August off Sydney. It’s not too late to start spotting, the humpback whale highway will be busy up until late October and November as the whales head back to Antarctica for the summer to feed.
Happy whale watching!
Dr Vanessa Pirotta