Your drive to the shops makes life pretty noisy for whales

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Living alongside humans gets noisier all the time.
Katrina Burgers/

Andrew J. Wright, Fisheries and Oceans Canada

As unlikely as it may seem, your drive to the supermarket is responsible for a lot of noise pollution in our oceans – and a lot of stress to marine life as a result.

Of course, it’s not the specific sound of your car trundling along the street that the fish and whales hear. But many of the products that feature in your weekly shop – from the goods you buy, to the petrol you burn, to your car’s component parts – contribute to marine noise pollution.

Read more:
Noise from offshore oil and gas surveys can affect whales up to 3km away

The fuel

Let’s start with the oil. Before we can drill the oil or turn it into fuel to drive our cars, oil companies have to discover it.

Companies look for oil using high-pressure airguns. These machines are towed across the surface of the ocean, firing off sounds to determine the make-up of sediment layers in the seafloor. These are some of the loudest human-created sounds – researchers working in the middle of the Atlantic Ocean have been able to record the sounds produced from coastal oil surveys.

Rex Virtual Drilling.
Chooywa/wikimedia, CC BY-SA

These sounds are problematic for marine life. Whales and other animals that rely heavily on sound for communicating and finding food are most affected. Hearing is to these animals much the same as vision is to humans. Unusually loud sounds can disturb whales’ behaviour and, if they are close enough, can damage their hearing. There is even some suggestion that the airguns can cause whale strandings, although this is not yet completely certain.

Currently, one-third of all oil comes from offshore sources and this proportion is expected to increase. This can only mean more bad news for our marine life.

The car

What about the metal box that consumes all the oil? Parts for the car are sourced from all over the world and have to be shipped across our oceans. In turn, the raw materials needed to make these parts are usually shipped in from yet more places. The commercial shipping needed for all this represents another problematic source of ocean noise.

The relative density of commercial shipping routes in our oceans.
B.S. Halpern/Wikimedia Commons, CC BY-SA

The contributions of individual ships may seem trivial in comparison to the loud noise from airguns. However, the world merchant fleet includes around 52,000 ships. Collectively, these increase the ambient noise levels in our oceans. In fact, the amount of low-frequency sound in some parts of our oceans has doubled each decade over the past 60 years.

Humans perceive only some of this sound, because of the very low pitches involved. But these sounds are well within the frequency range used by baleen whales. Recent work suggests that this constrains the communication ranges in whales, causing chronic stress and potentially interrupting mating behaviour.

Parts of the ocean are filling up with man-made noise, and that presents many dangers to marine life.
B. Southall/NMFS and NOAA

The groceries

Oh, and most of your groceries are shipped around the world at some point too, as are many other consumer items – including the battery in your hybrid car, if you have one. Around 90% of world trade is carried by commercial ships at some stage. Not all of this ends up in your shopping bag, but a large proportion enters the consumer market at some point.

Certain grocery items, such as fish, originate from the oceans themselves. Like cargo ships, fishing vessels produce noise from their engines and propellers, but they also have noisy fish-finding sonars and winches as well.

Read more:
10 tips for eating locally and cutting the energy used to produce your food

The solutions

The good news is that noise pollution, unlike chemical pollution, dissipates quickly. This means that the future for underwater noise remains bright. If you want to give the whales a break, just drive a little less, or support higher efficiency standards for vehicles. This will not only reduce oil consumption, but also the wear and tear on your car, meaning that fewer replacement parts will need to be shipped in.

Time for a rethink?
Joe Goldberg/flickr, CC BY-SA

You can also buy locally produced items and support the local economy too. That way everyone wins.

The ConversationNo matter how connected we think everything is, the situation is generally even more complicated than we can imagine. So next time you walk to the shops and buy an apple grown in your state, you should allow yourself a moment to feel good about yourself, safe in the knowledge that you have helped to make the oceans a tiny bit quieter.

Andrew J. Wright, Marine Mammal Researcher, Fisheries and Oceans Canada

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


Norway: Aurora Borealis and Orcas


What whales and dolphins can tell us about the health of our oceans

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Dolphins contribute important knowledge about ocean health.

Stephanie Plön, Nelson Mandela University

From the poles to the equator, marine mammals such as seals, dolphins and whales, play an important role in global ecosystems as apex predators, ecosystem engineers and even organic ocean fertilisers. The ocean off the coast of South Africa is home to a high diversity of these mammals and is recognised as a global marine biodiversity hotspot.

Marine mammals are often referred to as “sentinels” of ocean health. Numerous studies have explored the effects of both noise and chemical pollution, habitat degradation, changes in climate and food webs on these marine apex predators. Yet the interplay of these factors isn’t well understood.

Our research on the unfortunate dolphins incidentally caught in shark nets off South Africa’s KwaZulu-Natal coast has helped fill in some of the gaps. By assessing the health of these dolphins we have provided valuable baseline information on conditions affecting coastal dolphin populations in South Africa. This is the first systematic health assessment in incidentally caught dolphins in the Southern Hemisphere.

But to gain a fuller picture of the health of marine mammals in these waters I am now combining this contemporary field research with historical data, like the collection at the Port Elizabeth Museum Bayworld.

The combination of data on diet, reproduction, population structure and health helps us gain a better understanding of the pressures and changes these apex predator populations face. And it helps us understand it in relation to global change, including both climate change and pressures brought about by human behaviour.

My research sheds light on multiple factors: pollutant levels, parasites, and availability of prey, all have an impact on individuals as well as populations.

Understanding the health of these animals also gives us insight into the state of the world’s oceans. This is relevant because oceans affect the entire ecosystem including food security, climate and people’s health. This degree of connectedness is highlighted by recent discoveries about how whales act as ecosystem engineers.

The accumulation of this knowledge is important because the planet’s oceans aren’t being protected. Recent popular documentaries such as “Sonic Sea” and “Plastic Ocean” have highlighted their exploitation and pollution.

What’s missing

Without baseline knowledge it’s challenging to establish the potential effects that new anthropogenic developments (those caused by human behaviour) have on local whale and dolphin populations.

For example, we know that whales are sensitive to shipping noise, so what potential impact could a new deep water port have on mothers and their calves? Could it drive them away from these nursery areas, or could it lead to an increased risk of whales and ships colliding? To answer this and monitor the change that a new port brings with it, we are investigating the soundscape of two bays in the Eastern Cape (one with a new port, one without) in parallel with baleen whale mother-calf behaviour.

Another example is understanding how changes in the Sardine run over the past 15 years have affected the diets of these mammals. The Sardine run is an annual phenomenon when large shoals of Sardine migrate northwards along the coast into KwaZulu-Natal waters to spawn. Using long-term data and samples from the Port Elizabeth Museum research collection, we have been able to establish that over the the past 20 or so years the main predator in the Sardine run – the long-beaked common dolphin – has shifted its diet to mackerel. Although such changes in diet can have potential impacts on the health of the dolphins, parallel investigations on the trophic level these animals feed at (using isotope data from teeth) and the body condition of the dolphins (using long-term data on blubber thickness), indicated no adverse effects to the dolphins.

Our analysis highlights how marine mammals may be used as indicators of environmental change and why research is important.

Finding answers to intricate questions on environmental change is not always easy. But a better understanding and knowledge of the environment these animals live in has to be incorporated into studies contributing to their conservation and management. Such studies are becoming increasingly relevant as they highlight the fast degradation of the marine environment.

For example, a recent study identified antibiotic resistant bacteria in both sea water samples and exhaled breath samples from killer whales. This suggests that the marine environment has been contaminated with human waste which in turn has significant medical implications for humans.

Gaining such information is particularly important given the rapid changes taking place in the oceans, such as those on South Africa’s southern and eastern coastline. This includes increasing coastal development, new deep water ports being built or expanded, and parts of the deep sea being explored for oil and gas.

To assess these changes and what they mean for the environment, baseline studies need to be carried out so that potential effects can be assessed. Whales and dolphins are increasingly being recognised as indicators of ocean health in this endeavour.

And a continuation of the research we did on dolphins caught in nets will help document the cyclic changes that can be seen as normal variation in a population. This could prove important for assessing future catastrophic events, such as the Deep Horizon oil spill.

What next

The oceans absorb over 25% of the world’s carbon pollution as well as heat generated by global warming. They also produce at least 50% of the planet’s oxygen, and are home to 80% of all life on earth. Yet only 5% of this vital component of our planet has been explored.

The ConversationResearch on whales and dolphins contributes important knowledge about ocean health. Historical data increasingly provides a guideline to teasing out natural variations in populations and assessing the contribution that multiple factors have on these animals. In time, this will ensure that policy makers are being given sound scientific information. It will also provide us with a good barometer of the overall health of our oceans.

Stephanie Plön, Researcher, Earth Stewardship Science Research Institute, Nelson Mandela University

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


Noise from offshore oil and gas surveys can affect whales up to 3km away

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Migrating humpback whales avoid loud, nearby sounds.
BRAHSS, Author provided

Rebecca Dunlop, The University of Queensland and Michael Noad, The University of Queensland

Air guns used for marine oil and gas exploration are loud enough to affect humpback whales up to 3km away, potentially affecting their migration patterns, according to our new research.

Whales’ communication depends on loud sounds, which can travel very efficiently over distances of tens of kilometres in the underwater environment. But our study, published today in the Journal of Experimental Biology, shows that they are affected by other loud ocean noises produced by humans.

As part of the BRAHSS (Behavioural Response of Humpback whales to Seismic Surveys) project, we and our colleagues measured humpback whales’ behavioural responses to air guns like those used in seismic surveys carried out by the offshore mining industry.

Read more: It’s time to speak up about noise pollution in the oceans

Air guns are devices towed behind seismic survey ships that rapidly release compressed air into the ocean, producing a loud bang. The sound travels through the water and into the sea bed, bouncing off various layers of rock, oil or gas. The faint echoes are picked up by sensors towed by the same vessel.

During surveys, the air guns are fired every 10-15 seconds to develop a detailed geological picture of the ocean floor in the area. Although they are not intended to harm whales, there has been concern for many years about the potential impacts of these loud, frequent sounds.

Sound research

Although it sounds like a simple experiment to expose whales to air guns and see what they do, it is logistically difficult. For one thing, the whales may respond to the presence of the ship towing the air guns, rather than the air guns themselves. Another problem is that humpback whales tend to show a lot of natural behavioural variability, making it difficult to tease out the effect of the air gun and ship.

There is also the question of whether any response by the whales is influenced more by the loudness of the air gun, or how close the air blast is to the whale (although obviously the two are linked). Previous studies have assumed that the response is driven primarily by loudness, but we also looked at the effect of proximity.

We used a small air gun and a cluster of guns, towed behind a vessel through the migratory path of more than 120 groups of humpback whales off Queensland’s sunshine coast. By having two different sources, one louder than the other, we were able to fire air blasts of different perceived loudness from the same distance.

We found that whales slowed their migratory speed and deviated around the vessel and the air guns. This response was influenced by a combination of received level and proximity; both were necessary. The whales were affected up to 3km away, at sound levels over 140 decibels, and deviated from their path by about 500 metres. Within this “zone”, whales were more likely to avoid the air guns.

Each tested group moved as one, but our analysis did not include the effects on different group types, such as a female with calf versus a group of adults, for instance.

The ConversationOur results suggest that when regulating to reduce the impact of loud noise on whale behaviour, we need to take into account not just how loud the noise is, but how far away it is. More research is needed to find out how drastically the whales’ migration routes change as a result of ocean mining noise.

Rebecca Dunlop, Senior Lecturer in Physiology, The University of Queensland and Michael Noad, Associate Professor, The University of Queensland

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


Sperm Whale – Back From the Abyss


Sperm Whales