Why scientists need your help to spot blue whales off Australia’s east coast

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Vanessa Pirotta, Macquarie UniversityBlue whales, the largest animals to ever live, are surprisingly elusive.

They’re bigger than the biggest dinosaur ever was, capable of growing over 30 metres long and can weigh over 100 tonnes — almost as long as a 737 plane and as heavy as 40 elephants. They also have one of the loudest voices, and can talk to each other hundreds of kilometres across the sea.

Why, then, are they so difficult to find in some parts off Australia?

My new research paper recorded only six verified sightings of the pygmy blue whale off Sydney in the last 18 years. Two of these occurred just last year. This blue whale subspecies is known to mostly occur along Australia’s west coast.

Rare sightings like these are important because pygmy blue whales are a “data deficient” animal. Every opportunity we have to learn about them is crucial to help us better protect them.

Blue whales down under

Don’t let its name fool you, the pygmy blue whale can still grow shockingly large, up to 24 metres in length. It’s one of two blue whale subspecies that occur in Australian waters – the other being the Antarctic blue whale, the biggest whale of them all at around 33 metres long.

A blue whale lunging for krill.

Unfortunately, historical whaling hunted blue whales to near extinction in the Southern Ocean. The Antarctic blue whale was depleted to only a few hundred individuals and, while they’re slowly bouncing back, they’re still listed as critically endangered by the International Union for the Conservation of Nature (IUCN).

In contrast, we know little about pre- and post-whaling numbers for pygmy blue whales. Their listing as a data deficient species by the IUCN means we don’t have a full understanding of their population status.

Blue whales can grow to around 30 metres, almost the same length as a 737 plane.
Vanessa Pirotta, Author provided

One reason may be because blue whales are logistically challenging to study. For example, blue whales don’t just hang around in one area all the time. They’re capable of swimming thousands of kilometres for food and to breed.

They can also hold their breath for up to 90 minutes underwater, which can make them hard to spot unless they’re near the surface. To see them, people need to be in the right place at the right time.

This may require scientists to be on dedicated research vessels or in a plane to spot them, which can be expensive and weather-dependent.

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This also makes learning about them much harder compared to other, more accessible species, such as coastal bottlenose dolphins.

To learn more about pygmy blue whales in Australia, marine scientists have developed a variety of techniques, including listening to whales talking, taking skin samples and satellite tagging.

While this work is useful, it has focused mainly in areas where pygmy blue whales are known to occur, such as southern and western Australian waters.

Pygmy blue whales are known to feed in the Perth Canyon, Western Australia, and between the Great Australian Bight and Bass Strait during summer. They most likely breed in the Indian and western Pacific Oceans during winter.

But we don’t know much about pygmy blue whale presence in other parts of Australian waters, such as the east coast.

Bottlenose dolphins are more commonly seen.
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How can we conserve a species we know very little about?

Well, it can be tricky. The more information we know, the better we’re placed to assess their conservation needs. But focusing our efforts on species we know nothing about may require a conservative approach until we learn more.

Some would argue it’s better to protect a species we know needs our conservation dollar before spending precious resources on something uncertain.

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Fortunately, Australia has some of the world’s best protection policies for marine mammals, including whales. This means a precautionary approach is already in place to protect these creatures.

Since blue whales are listed as a threatened species, they’re protected under Australia’s primary environment law, the Environmental Protection and Biodiversity Conservation (EPBC) Act.

And on an international level, Australia is a signatory to the International Whaling Commission (the global body for whale conservation) and the Convention on International Trade of Endangered Species (which ensures wildlife trade doesn’t threaten endangered species).

Citizen science sightings help contribute to our understanding of blue whale distributions in Australian waters.
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To help uphold this international and national protection, scientists must continue to learn more about data-deficient animals like the pygmy blue whale to help safeguard against known and future threats.

This includes collisions with ships, overfishing, entanglement with fishing gear, increased human activity in the ocean, and climate change, which may affect when and where whales occur.

We need extra eyes

There are more than 14,600 animal species listed as data deficient by the IUCN.

Some, like the pygmy blue whale, are poorly studied. One reason is because they’re cryptic or boat shy, such as the Australian snubfin dolphin.

Or, they might be tricky to see, such as the false killer whale, whose sightings remain irregular in Australian coastal waters. Opportunities to learn more about them occur when they become stranded.

False killer whales are another data-deficient marine animal.
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So while citizen science sightings of pygmy blue whales may be rare off the Australian east coast, they do help contribute to our understanding of their distribution in Australian waters.

The two sightings of pygmy blue whales off Maroubra, Sydney, last year were within two months of each other. This was thanks to drones (flown under state rules).

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This prompted my research review of blue whale sightings off Sydney, which found citizen scientists made similar sightings in 2002 – the first official sighting from land off Sydney — and between 2012-14.

We don’t know exactly what type of pygmy blue whales these are (three distinct groups are recognised: the Indo-Australian, New Zealand and Madagascar groups). However, whale calls detected along Australia’s east coast in previous years suggest they’re most likely New Zealand pygmy blue whales, and they could have been heading to breeding waters north of Tonga.

So, the next time you are by the sea, keep a look out and tell a scientist via social media if you see something interesting. You just never know when the world’s biggest, or shiest, animal may turn up out of the blue.

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Vanessa Pirotta, Wildlife scientist, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Curious Kids: which is smarter – a blue whale or an orca?

Blue whales and orcas are both specialists in their own way. You can’t really measure which one is more intelligent.
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Kerstin Bilgmann, Macquarie University

If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au.

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Which is smarter: blue whales or orcas? – Prasaad, age 6.

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There’s no simple answer. We don’t know for sure which one is smarter, because not everyone agrees on what “intelligence” means.

It’s true that blue whales and orcas (also called killer whales) are both smart. They both have very large brains. Orcas have particularly large brains compared to their overall body size.

But it’s not just about brain size. When it comes to measuring intelligence, we might also consider things like:

• the number of nerve cells in the brain;
• ability to navigate the deep, wide oceans;
• solving difficult problems;
• communicating;
• working in teams.

Let’s look at which animal is good at which skill.

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Curious Kids: What sea creature can attack and win over a blue whale?

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What can a blue whale do?

There’s no doubt a blue whale is a very intelligent animal.

Blue whales eat krill, which are very tiny prawn-shaped animals that gather in huge swarms that are often far away from where blue whales give birth to their children. Despite the distance, blue whales are masters of finding krill. They are very good at navigating along coasts and across the deep, wide oceans.

In fact, blue whales are so smart they can work out if a swarm of krill is worth chasing. Blue whales are very good at finding krill that are fat and in big swarms so they do not waste their energy catching smaller swarms. Blue whales catch krill by rolling on their side and opening their mouths. It is a lot of work and they have to use a lot of energy to do it.

Blue whales also have excellent systems for communicating with each other.

What can an orca do?

Orcas are a kind of large dolphin and they have different strengths.

They are very good at working together. They form groups and hunt together for fish or other sea mammals – including whales. This is why they are called “killer whales”.

They are also expert communicators and have their own language – even certain noises that are used by a particular group of orcas to show they are in the group.

Orcas form groups and hunt together.
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They both are very intelligent in their own way

Some scientists have wondered if you could measure intelligence by looking at how well animals teach their children how to behave – for example, how to find food, fight or stay safe.

Orcas are masters at teaching their children exactly what to do. This involves things like hunting in groups or sneaking up on a seal and grabbing it before sliding back into the water.

However, blue whales are also good at teaching their offspring skills such as long-distance navigation – in other words, finding their way around the vast oceans.

Both blue whales and killer whales have their own special behaviours and skills. We really can’t say which one is more intelligent because both are very intelligent in their own way.

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Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au

Kerstin Bilgmann, Lecturer in Biological Sciences, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Curious Kids: What sea creature can attack and win over a blue whale?

Blue whales are the largest creatures to have ever lived on Earth.
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Wally Franklin, Southern Cross University and Trish Franklin, Southern Cross University

This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky! You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

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What sea creature can attack and win over a blue whale? – Drake, age 7, Sydney.

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Hi Drake. That is an interesting question.

As you probably know, blue whales are the largest creatures to have ever lived on Earth – bigger than any dinosaur. They can grow up to 30 metres in length and weigh over 150 tonnes. This is very, very BIG. To give you an idea of how big a blue whale is, it’s the size of a Boeing 737 plane! Because of their size, power and speed, adult blue whales have virtually no natural ocean predators.

The only sea creature known to attack blue whales is the orca whale (scientific name: Orcinus orca) also known as the “killer whale”. They have been known to work in groups to attack blue whales.

However, there are very few reports of orcas actually killing blue whales. We know that orca whales interact with them because many blue whales carry scars from the teeth of orcas. But blue whales probably see orcas as more of a pest than a predator.

Orcas have sharp teeth.
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Blue whales can grow 30 metres in length and weigh over 150 tonnes.
Kurzon/Wikimedia Commons, CC BY-SA

The human threat

A much more serious problem for blue whales is humans. Humans have caused a lot of trouble for blue whales over the years.

One big problem is what we call “ship strikes”. This is when large ships collide with blue whales causing dreadful wounds and, in many cases, death.

Blue whales migrate freely across all the great oceans of the world to breed. They travel each year to the Antarctic in search of food. Global warming is a major future threat to their way of life. This is because rising sea temperatures and ocean acidification (which are caused by climate change) are likely to cause severe disruption to the production of their main food source, the very small crustacean we call “krill”.

Blue whales were the target of commercial whalers, mainly in Antarctica, between 1900 and the 1970s. During that time, over 330,000 blue whales were killed.

Fortunately – and only just in time – the International Whaling Commission banned commercial whaling in 1966. Blue whales are now a protected species and are recovering from the brink of extinction. People on whale watching trips at various locations around the world can see them, if they are lucky. The risk of whaling still exists in several countries, including Japan, Iceland and Norway. Many people in these countries are seeking to return to commercial whaling. Recently, whalers in Iceland killed a hybrid blue whale.

Blue whales can talk

One of the most interesting things about blue whales is that they use very low frequency sounds to communicate. Through this they can talk to each other over great distances. The low frequency sounds can pass through the earth, so it’s possible to record their songs and sounds from anywhere in the world.

In the 1960s, an American scientist called Chris Clark got permission to use the USA’s submarine listening system across the Atlantic Ocean to listen to blue whales. One day, he heard a blue whale calling from the far northeast Atlantic Ocean and realised another whale many thousands of miles away in the southwest Atlantic Ocean was answering it. Through their calls, he tracked them over the next few weeks moving towards each other. The two blue whales met and spent time together in the middle of the Atlantic. Then they separated and went on their way!

A pair of blue whales swims under the surface in Monterey Bay, California.
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It is important for all who are interested in the conservation and protection of these amazing creatures to remain vigilant and involved in making sure that they remain safe. Whales are part of the international heritage of all people of the Earth.

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Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. They can:

* Email your question to curiouskids@theconversation.edu.au

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Please tell us your name, age, and which city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question but we will do our best.

Wally Franklin, Researcher and co-director of the The Oceania Project, Southern Cross University and Trish Franklin, Researcher and co-director of The Oceania Project , Southern Cross University

This article was originally published on The Conversation. Read the original article.

Antarctica’s blue whales are split into three distinct populations

Catherine R. M. Attard, Flinders University; Luciana Möller, Flinders University, and Luciano Beheregaray, Flinders University

Antarctica’s critically endangered blue whales, the world’s largest animal, are made up of three populations, according to our new DNA analysis.

Although the groups occur together when feeding in Antarctic waters, they are genetically distinct. This suggests that the three groups breed in different locations – possibly even different oceans – when they head north in the winter.

If we can find out where they go, and what hazards they face on the way, we will be a step closer to helping them recover from their near-annihilation by whalers during the 20th century.

Hidden giants

It is a daunting task to understand the ecology of the Antarctic blue whale (Balaenoptera musculus intermedia). Even though they can weigh more than 160 tonnes – the heaviest ever known animal – and reach more than 30 metres in length, locating such a rare and highly mobile species in a vast and remote ocean can be like finding a needle in a haystack. And even having tracked them down, it can be hard to deduce anything about their population structure.

The largest animal in the world.
Paula Olson, courtesy of IWC

By comparing similarities and differences in the DNA of individuals, we can tell which individuals are part of the same population and estimate the number of populations. Individuals from the same breeding population are more genetically similar than those from different populations. But we need recently collected DNA samples to do this for current populations.

The standard way to get DNA from a blue whale is to take a biopsy by firing a dart that collects a small piece of skin and blubber, bounces off the whale and floats on the water for collection. It is akin to a pinprick for an animal as massive as a whale.

Long before we started working with blue whales in 2007, expeditions have been carried out under the auspices of the International Whaling Commission to research Antarctic whales. These expeditions involved collecting precious biopsy samples from blue whales and there is now a collection stretching back to 1990.

We were granted access to samples, totalling 142 whales, and used these to create the largest and therefore most powerful genetic data set so far created for Antarctic blue whales. As our research published in Nature’s Scientific Reports shows, we found that these whales fall into three genetically distinct groups.

Where are these populations?

Blue whales, like many other whales, migrate between their Antarctic summer feeding grounds and their winter breeding grounds at lower latitudes.

We know Antarctic blue whales feed in the Antarctic, which is where they were hunted during whaling in the 20th century and where the biopsy samples were collected.

We found that individuals from the three populations occur together throughout the Antarctic, although possibly in different proportions in different areas. This is probably because the blue whales need to rove long distances around Antarctica to find the massive amounts of krill that make up their sole food source.

https://c311ba9548948e593297-96809452408ef41d0e4fdd00d5a5d157.ssl.cf2.rackcdn.com/2016-08-03-distribution-of-whale-populations/whales.html

Distribution of samples from the three genetically distinct populations of Antarctic blue whales

We suspect that the three populations go their separate ways when they head north to breed – presumably heading into the three major Southern Hemisphere ocean basins: the South Pacific, South Atlantic and Indian Oceans.

The next step will be to confirm this by finding their breeding grounds. This would involve satellite-tagging whales in Antarctic waters and then watching where they go. More biopsy samples could then be taken at the breeding grounds to confirm which populations are which.

Knowledge for conservation

Understanding the number of populations and their distribution is vital for helping Antarctica’s blue whales recover from 20th-century whaling, which reduced their numbers from 239,000 to just 360 individuals. While they are now protected from whaling, they remain critically endangered.

Some populations may be more endangered than others and may face different human threats along their migration routes and at their breeding grounds. Failing to take conservation action at a population level could therefore lead to local extinctions at these locations.

One threat that differs in intensity between locations is noise pollution, such as from seismic surveys for oil and gas as well as shipping activity. These noises can be heard underwater hundreds of kilometres from their source. Whales communicate through sound, so noise pollution can hinder their communications or, in extreme cases, make areas uninhabitable.

Our latest findings, together with our previous work on hybridisation, connectivity and population history of blue whales, provides important pieces in the puzzle of this species. But we are still at the tip of the iceberg in our understanding of the world’s largest animal and in the pathway to their recovery from whaling.

Catherine R. M. Attard, Lecturer in Molecular Ecology, Flinders University; Luciana Möller, Associate Professor in Marine Biology, Flinders University, and Luciano Beheregaray, Professor in Biodiversity Genetics and ARC Future Fellow, Flinders University

This article was originally published on The Conversation. Read the original article.

Speak of the Whale

Video: Blue Whales and Bottlenose Dolphins