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New north whales as migration season underway

Whale migration season is underway as tens of thousands of cetaceans swim north along Australia’s east and west coasts on their journeys to warmer waters, before returning south for the summer.

From May until August each year during winter months, many species of whales cruise northward to feed and breed. Then, from mid-August until November, they return southward, the early southbound travellers passing the late northbound, often pausing to socialise as they cross paths.

Only a few species of dolphins migrate, often travelling in pods alongside the whales, and they trek significantly shorter distances, following the seasonal movement of fish upon which they prey.

The last stragglers of the southbound migration in October-November are typically whale mothers with their newborn calves, the latter learning the routes of the vast distances they cover whilst developing stamina. They usually swim closer to the shore to avoid hungry predators like orca, which roam in packs looking for vulnerable young whales.

Orca, adult and young. Photo: PXFuel

Ocean Extreme, a whale watching company that supplied us with the recently-taken double-breaching humpbacks photo (above, top), revealed Sydney coastal waters are full of whales at present.

Captain Blake Horton told Manly Observer, “We have only had 3 trips this season that haven’t seen whales. There are so many around at the moment. The whales are constantly migrating past Sydney…  We had the double breach two weeks ago which was incredible.”

Ocean Extreme depart 1-3 times a day in a 12 metre rigid-inflatable, twin-engine speedboat, and collect up to 21 passengers from Manly Wharf East and Circular Quay.

When the calves swim with their mothers on the whales’ return migration at the end of winter, do different rules apply concerning how close whale watching vessels can venture?

“Yes, you have to stay 300m away from a calf,” Blake said. “However that is difficult as the calves are often very curious about the boats and decide to approach. In which case you have to sit in neutral and wait for them to depart. Which can be over an hour sometimes.”

It’s been reported that on the whales’ return journey south they are more likely to engage in ‘mugging’, in which groups of them show curiosity in vessels they encounter along their migration route, and close in to inspect them. Is this true?

“Yes, definitely,” Blake replied. “Everyone wants to see a breach, however, I much prefer the muggings. It’s amazing watching them interact with the boat.”

This must be thrilling for the passengers, but do the whales nudge the vessels or behave recklessly, like breaching alongside?

“The whales have never touched the boat in the 10 years I’ve been doing this,” he insisted. “They are especially aware.”

Whale breaching in waters off Sydney. Photo: Ocean Extreme whale watching tours

Threats

The La Niña extreme weather event that rolls in every five to seven years impacted East Coast Australia during the summer of 2021-22, bringing high tides and torrential rains.

Although the storms arrived in November 2021 at the end of the whale migration season, and subsided at the start of their 2022 migration (May), will the human refuse flushed out from stormwater drains and tidal rivers, including increased levels of disposable plastic bags, adversely affect cetaceans?

Jools Farrell, Vice President of ORRCA (the Organisation for Rescue and Research of Cetaceans in Australia), said she believed the East Coast Lows and accompanying tidal surges haven’t had a significant effect on the annual whale migration.

“There was a lot of debris washed out during the storms,” she confirmed, “but whether it will have an impact remains to be seen. When necropsies have been done on whales that were stranded over the last few years, we’ve not noticed any with stomachs full of plastic.

“However, climate change will have an adverse effect on whales, because it reduces their feeding grounds. It’s a big concern because it will also affect the times and range of their migration as well as breeding cycles. Furthermore, whale poo (Faecal Plumes) is very important for what is a delicate eco-system. It’s full of iron and nitrogen and feeds plant plankton. In turn plant plankton feeds the animals of the sea such as Krill and whales rely on krill as a major food source as well as reducing carbon so the more whales the better.”

ORRCA is the only volunteer wildlife group in NSW licensed to deal with marine mammal rescue, rehabilitation and release. They also assist NPWS Disentanglement Team & SeaWorld Disentanglement Team with the monitoring of entangled whales from ropes and floats and nets. Jools revealed that nets and ropes and floats across beaches & in the ocean are a major hazard to migrating whales.

Oct 2021, Bungan Head, young whale entangled in shark net it dragged for six days from Queensland. Screenshot: Channel7

In October 2019, for example, off Bungan Head near Newport, a young humpback was intercepted by specialists and cut free from a shark net it had part-swallowed and dragged all the way from Queensland over the previous six days. The whale and its mother swam a further 100kms to Wollongong with the rescuers alongside working to free it before the operation was complete.

On 22 October 2013, a baby humpback became entangled and drowned in a shark net at Mona Vale Beach with its distressed mother nearby unable to assist.

Shark nets are often removed during the winter months, but reinstalled in September, just as the whale mothers and their calves are returning south.

“We feel shark nets shouldn’t be replaced until the end of November, and removed completely during the whale migration season,” Jools recommended. “They are a false sense of security anyway – sharks can swim over, under and around them also the bycatch is a major problem.

“In October 2021 I was at Whale Beach where the NPWS Disentanglement Team took five and a half hours to disentangle a juvenile Humpback caught in the nets on its southern migration. The whale was exhausted because the nets were attached to the bottom. It couldn’t move because it swam into them and rolled and became heavily entangled. The nets had only been in place for a week.

“Disentangling whales is extremely dangerous work, especially if it’s a young whale with the mother nearby, because she tries to protect her calf. The rescuers are specially trained and operate from boats – you never get into the water with an entangled whale. They use long poles with knives on the end that they manoeuvre under the ropes to cut away the netting.

“There were 24 whales caught in ropes and floats in 2021, and 44 the year before that. This year we’ve encountered three so far, caught in ropes and floats. One was seen trailing three yellow buoys. They were embedded into the flesh of the whale’s tail so the whale could have become entangled last year and had been dragging the buoys around since. This whale was successfully disentangled. Some gear source owners are trying to mitigate impacts on the migrating whales.”

Whale entangled in shark netting off the Gold Coast, August 2021, freed by SeaWorld.  Screenshot: Sunrise/Channel 7 TV

Cetacean types

Cetaceans – of which there are 86 species of whales, dolphins and porpoises worldwide – are all marine-dwelling carnivores with diets that range from miniscule plankton to fish to other whales. The word cetacean is derived from the Ancient Greek ‘ketus’, meaning ‘monster-sized fish’, although they are not fish but warm-blooded mammals that give birth to live young, breathing air through a nostril ‘blowhole’, not filtered through gills.

45 species of cetacean are found in Australian waters, including 10 large whales, 20 smaller whales, 14 dolphins and a single breed of porpoise. Some of them are seasonal, others resident all year round.

Cetaceans can be divided into two categories of feeders: the baleen with thin, frayed-end strainers for teeth through which they filter small marine creatures like plankton and fish; and the toothed whales that generally prey on fish and squid, although some, like the aforementioned orca (which are actually large dolphins and not whales, despite their name ‘killer whales’), also hunt seals or other cetaceans.

Some whales ‘herd’ shoals of fish in an intelligent tactic requiring group cooperation. After surrounding a school of fish, one dives below, then exhales carbon dioxide from its blowhole, which has the effect of enshrouding the fish in clusters of spiralling bubbles and disorienting them.

Another whale emits a loud noise beneath the confused fish, which panics them into swimming upwards to attempt escape. The herding whales then form a tight circle to follow their prey upward, their mouths agape to swallow the doomed fish at the surface.

Humpback whale. Photo: Elianne Dipp/Pexels

Whales

Among the baleen whales, the Bryde’s, fin, humpback, minke (Antarctic and its dwarf subspecies), right (both southern and pygmy) and sei whales can all be sighted off the coast of Sydney. Blue whales too, albeit once in a blue moon.

Toothed whales witnessed offshore include southern bottlenose, pilot (long and short-finned), melon-headed, sperm (including pygmy and dwarf sub-species), and the multitude of ‘beaked’ species (Andrew’s, Arnoux’s, Blainville’s, Cuvier’s, ginkgo-toothed, Gray’s, Shepherd’s and strap-toothed).

Humpbacks, which feature distinctive fluted chins and long fins with up to 11 bumps known as ‘tubercles’, are the most common whale seen off Australia’s east coast. Their annual migration takes them between the Antarctic Ocean (their summer habitat) and the Coral Sea (winter) in the South Pacific Ocean. An estimated 30,000 of the estimated 80,000 worldwide travel up and down the east coast of Australia every year.

Humpbacks and grey whales travel the longest distances of all whales – some swim a 10,000km round trip during their migratory cycle! Males often leap completely out of the water – known as ‘breaching’ – during demonstrations of strength generally intended to impress females.

Curious dolphin. Photo: Pixabay

Dolphins

A variety of dolphins inhabit the coastal waters of the Pacific Ocean around Sydney and are often seen in our bays and inlets. Species include bottlenose, common, dusky, hump-backed, Indo-Pacific, Risso’s, rough-toothed, spinner, striped, pantropical, and the orcas (including false killer whales and pygmies).

Dolphins are amongst the most intelligent creatures on Earth, and can learn and memorise complicated tasks as well as plan ahead. They’re sentient enough to recognise themselves in mirrors, feel empathy and display complex emotions like grief and elation. They also communicate in their own complex ‘language’ which they utilise for hunting, defence and raising their young, as well as amusing themselves in surfing spectacles, sometimes performed in synchronicity.

They are among the most acrobatic of all living creatures: spinner dolphins, in particular, can twist and somersault several times whilst leaping from the sea.

Spectacled porpoise, the only species of porpoise in Australian waters. Photo: Wikimedia Commons

What differentiates dolphins and porpoises?

Although dolphins and porpoises both navigate underwater via sonar from the ‘melon’ in their foreheads, they have significantly different faces, figures and fins.

Porpoises have rounder faces, smaller mouths and spade-shaped teeth whereas dolphins have elongated ‘beaks’ with cone-shaped teeth.

Porpoises are portly but dolphins are more streamlined. Porpoises have a triangular dorsal fin, like a shark, whilst dolphins’ fins curve.

However, dolphins often attack and kill porpoises in competition for food and territory.

Dolphins communicate via complicated whistling sounds through their blowholes, but scientists believe porpoises are incapable of making these noises due to the different shape of their blowholes.

There are 37 dolphin species worldwide (including five freshwater breeds of river dolphins) yet only six types of porpoises.

The single porpoise species in Australian waters – spectacled – inhabits cooler waters south of Tasmania and is not seen along the east coast of mainland Australia.

Whale Watching boat cruises around Sydney:

https://oceanextreme.com.au/  (includes departures from Manly Wharf)

https://www.whalewatchingsydney.com.au/

https://gowhalewatchingsydney.com.au/

https://www.captaincook.com.au/sydney-harbour-cruises/explore/whale-watching/

https://www.fantasea.com.au/whale-watching/

https://www.cronullawhalewatching.com.au/

If you spot injured or entangled cetaceans, contact ORCCA on 9415 3333

A humpback eyes Sydney city from the mouth of the harbour.  Photo: Ocean Extreme whale watching tours

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