CASE STUDY: Spearheading world action for killer whales – by listening to them

Focusing on acoustic research, University of Cumbria’s Associate Professor in Wildlife Conservation, Volker Deecke (below) has been able to eavesdrop on orca communication, interpreting sounds made by the largest member of the dolphin family.

In an influential career, he has played a pivotal role in collaborative research, which has assisted governments in Canada, Iceland, USA and the UK in assessing the status of killer whales in their waters.

His work has put him at the forefront of informing international protection policies and raising awareness of the beautiful black and white animals with sophisticated hunting techniques and compelling vocal characteristics, often specific to a particular group and passed across generations.

Over nearly three decades, he has deployed underwater microphones, digital recording tags and self-contained automatic recorders on the sea floor, identifying calls, clicks and whistles to learn about population structure, social interactions and feeding behaviour.

Although one of the most familiar and well-known cetaceans, killer whales globally are classed as data deficient by the International Union for Conservation of Nature. Despite a worldwide lack of information, several studied populations are now considered endangered.

Dr Deecke explained: “Whilst those I have studied in Iceland, northern British Columbia and Alaska are reasonably healthy, southern residents in British Columbia and Washington State have been declining since the 1970s.

“Our research is very collaborative and we all contribute pieces to a puzzle that will hopefully lead to better management and protection strategies.”

More recently, Dr Deecke’s work using digital recording tags has helped open new windows on behaviour, feeding patterns and, crucially, the impact of underwater noise.

These invaluable insights are made possible by tags the size of a mobile phone and attached to whales by four suction cups, using a five-metre pole from a research boat, designed to minimise disturbance.

“It’s been very exciting,” he admits, “shedding new light on what goes on beneath the waves. Before this, we were limited to observing whales on the surface where they only spend five percent of their time.

“Tags have given us the opportunity to plot dive paths in three dimensions and record the sounds the whales detect and make. Hearing them opens a fascinating window on to their world. I like closing my eyes as I’m listening, imagining what it’s like down there.

“You need intricate knowledge of their behaviour to slowly approach and tag them. We may see a slight flinch when the tag is deployed, but the dive data shows they quickly resume normal activities.

“Between 2009 and 2012, we tagged 34 northern residents off Vancouver Island, classified as ‘threatened’ in Canada, but with a stable, even slightly increasing, population.

“In 2019, we tagged six more and the results are being analysed, particularly against southern residents to explain the different trajectories. The work continues.”

Underwater noise is a big concern for orcas. Sounds from boats, naval sonars, industrial operations like offshore windfarms and seismic surveys for oil and gas, create an impact for whales and dolphins.

Dr Deecke explains: “Even though there are increasing trends to use marine mammal observers and only progress operations if there are no sightings nearby, deep-diving and more distant animals are not detected, but can still be affected.”

In the first trial of its kind anywhere in the world, vessels approaching the Port of Vancouver were asked to voluntarily slow-down to minimise sounds from propellers and engines, lessening the impact of ship noise on endangered southern resident orcas.

“Global shipping is an area where considerable gains could be made by designing commercial freight carriers that are quieter,” argues Dr Deecke. “The slow-down trial is the first step towards creating economic incentives to build less noisy ships and cut noise.

“Our work in western Canada showed that even in this relatively remote area, northern residents were experiencing some sort of anthropogenic noise for a majority of the time.

“However, for southern residents in busy waterways off south British Columbia and Washington State, the problem is even greater.

“Technology to make vessels quieter exists. The military have used it for decades to make naval ships less detectable and it could be used in designing commercial freighters that produce less noise.”

To properly understand the world of killer whales, Dr Deecke has listened to their voices, not just to discover the impact of noise pollution, but to find out how and where they feed, about their social lives, and, crucially, what disturbs them.

Far from idle chatter, their underwater calls are essential communication signals between the animals so that they can find and identify each other.

Their sounds include whistles and pulsed calls, allowing whales to communicate over tens of kilometres. Echolocation clicks sound a bit like a creaking door and are used for navigation and to find prey.

Pulsed calls of some fish-eating populations even have dialects, with different family groups making distinct sounds. Because their prey has excellent hearing, mammal-hunting populations use their sounds sparingly to avoid alerting seal, sealion and porpoise prey.

Dr Deecke was born in Germany and brought up in Austria where his interest in animal behaviour developed at a young age. While studying biology in Berlin, he had the opportunity to volunteer at a research station on Vancouver Island with the irresistible prospect of studying underwater communication.

He soon moved to Vancouver where he completed his master’s investigating the evolution of dialects in resident fish-eating orcas. This led on to his doctorate from Scotland’s University of St Andrews and the emphasis on vocal behaviour of mammal-eating killer whales in British Columbia and Alaska.

“In the 27-years I have been studying killer whales there have been notable changes, for better or worse,” he says.

“Our research in Shetland and Iceland used photographic identification and analysis of calls to show that individuals frequently travel between the coastal waters off both countries – making it clear that conserving killer whales effectively requires international collaboration.

“Persistent organic pollutants, toxic substances which take a long time to break down and accumulate in the food chain, continue to present a considerable threat. The higher up the food chain an animal is, the greater its exposure. Top predators like killer whales and polar bears are particularly vulnerable.

“Persistent organic pollutants in industrial coolants and flame retardants, commonly used in plastics and textiles, can cause disease and death when immune response is reduced. Many of the chemicals are being regulated, but the effects are global and will take centuries to clear from the environment.

“Pollutants don’t respect borders and neither do whales. Effective conservation requires nations to collaborate on mitigating these global threats and implement conservation measures.”

Where there has been intervention and conservation legislation it has made a difference, as Dr Deecke explained.

“Southern residents and Icelandic populations were hit when individuals were captured for display in aquaria.  Fortunately, this ended in the mid-70s in America and 10-years later in waters off Iceland.

“Varying populations feed on different things, but food supply is a big concern for several of them. Along the western coast of North America mammal hunters were greatly affected by government culling of seals and sea lions, with severe consequences. Since this was stopped in the 1970s, they seem to be doing well in terms of survival and new births.

“However, those that feed on fish, like southern residents, are of particular concern as a major food source is Pacific salmon, particularly Chinook, which is becoming increasingly rare because of degraded spawning habitat and poor ocean survival. Chinook makes up to 80 percent of the diet of northern and southern resident killer whales.”

The work continues, with exciting plans afoot to study killer whales in Scottish waters, but that is another story.

Images

Dr Volker Deecke, picture credit Milaja Nykänen

Northern resident killer whale with an acoustic tag, picture credit Volker Deecke

Dr Volker Deecke with a radio antenna to locate an acoustic tag, picture credit David Gaspard