We tend to think of the air-water interface as a barrier to noise. Planes fly over the ocean all the time, but conventional wisdom tells us that most of the sound bounces off the surface of the ocean, and has little impact on the whales and dolphins that swim beneath the surface. A classic paper from 1972 tells us we only need to worry about airplane noise in a narrow cone under the flight path.
Planes fly pretty quickly of course, so any noise exposure is fleeting. But during the busiest periods, we recorded planes taking off every 3 minutes! Below is a map of runways, with coastal runways (<10 m above sea level) in red.
We conducted this study during Nyepi, the Balinese Day of Silence. We did not expect to be able to hear airplane noise over background conditions, but we got lucky. Did you know that fish have a chorus of song, just like the dawn chorus of songbirds? Check out the sounds of fish singing below:
And this is the sound of a small boat passing by our hydrophone. In the last few seconds, you can hear the roar of a jet aircraft taking off from the nearby runway of Denpasar airport, Bali, Indonesia.
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Runways of the world, with coastal (<10m above sea level) marked in red
We need to recover Chinook salmon stocks throughout the whales’ range.
We support all efforts to do so. We support dam removal, where this will get more salmon into the environment. We applaud the recent announcement to reduce salmon fishing quotas until the whales recovery, which will reduce our competition with the whales. While we wait for those measures to take effect, we need your help to give the whales a fighting chance to find as many of those salmon as possible in a noisy ocean.
We need to give the whales a quiet place to hunt for salmon
A protected area can help the whales if we put it in the right place.
We have found that killer whales are more vulnerable to disturbance when they are feeding than when they are travelling from A to B. They also need more salmon. We have identified areas that whales use preferentially for feeding. (One is called Salmon Bank. We have a feeling the whales knew this before people did.) We need to bring together all dedicated datasets we can use to identify areas where the whales are finding salmon, so we can prioritize those for protection. Protecting key feeding areas is essential to protecting the whales.
Please support our efforts to keep orca habitat clean, quiet, and full of fat, wild salmon.
PS Thanks to our team, especially Toby Hall, for the great footage, and to our friends at SeaLegacy for help editing this video.
Southern resident killer whales in Haro Strait. Photo by Toby Hall
Southern resident killer whales are in decline. Our recent population viability analysis on southern resident killer whales predicted that, if threats remained constant, it should take several decades for the population to decline from 80 to 75 whales. In fact, that decline took only three years. We fear that the decline is accelerating, and we may be reaching a tipping point.
By studying killer whales from land, we can measure their responses to noise without adding the noise of a research boat to the equation. We use noninvasive techniques to measure swimming speeds, breathing rates, and other behavior. Our work on both northern and southern resident orca has shown us that the whales spend 18-25% less time feeding in the presence of boats than in their absence.
We recently joined an international, interdisciplinary study to understand the relative importance of the three main threats to recovery in the endangered killer whale population. The whales are facing a perfect storm of threats–not enough salmon, too much noise, and too many toxic chemicals in their bodies–but lack of prey is at the eye of the storm. This research shows it will take 30% more big, fatty, Chinook salmon than we’ve seen on average over the last 40 years for the population to reach our recovery goals. That will take time, but we have to start now. Meanwhile, reducing noise and disturbance can help make it a little bit easier for whales to find the salmon we have now. In the coming months, we will be revisiting our study on identifying critical foraging areas in the Salish Sea and strengthening their protection.
Humpback whale flukes with killer whale rake marks (PC: Laura Bogaard, for Oceans Initiative)
It was another beautiful day in the North Island neighborhood and Team Dolphin was all aboard our trusty research vessel, Wishart. We were cruising up Tribune Channel in search of our study animal, the Pacific white-sided dolphin (Lagenorhynchus obliquidens). The water was a magnificent pale blue—a reflection of the late-summer sky, and an indicator that this channel was once the path of an enormous glacier, which carved out the intricate valleys that make up the channels and inlets of the Broughton Archipelago.
All eyes were squinted against the glare as we scanned the waves for fins or splashes—any indication that there were dolphins in our midst. Off in the distance, three tall columnar blows gave away the position of a group of three humpback whales (Megaptera novaeangliae) making their way down the channel in our direction. We decided to slow our course in order to snap a few ID shots. We waited a few minutes for another surfacing and then, as if on cue, three more blows erupted through the surface almost in unison. One right after the other, each whale turned and dove deep into the blue water, flipping their tails and exposing their flukes as they descended. Armed with rapid reflexes and two spectacular cameras, Rob and I were able to grab ID shots for each whale in the short window of time that their flukes were vertical and above the water.
This is a photo I took from that encounter. The dark parallel lines you see are killer whale (Orcinus orca) rake marks that this whale probably sustained during a run-in with a transient orca. The scars left behind will help lead to an individual identification of this particular whale. Even after seeing them almost everyday this month, the size and agility of these creatures still astounds me.
The humpback’s smaller and speedier cetacean cousins, the Pacific white-sided dolphins, had the spotlight this season for Erin and Rob’s research project. They were quite a bit trickier to photograph than the humpback whales because of their speed and unpredictable behavior. After a month of working with them almost every day and shooting thousands of photos, I feel like I am finally getting the hang of it. Photographing wildlife can be a challenging experience, but with the right amount of patience, persistence, and positivity, the results are incredibly rewarding.
My favorite job on the boat was operating the hydrophone. Like photography, there was a bit of a learning curve. It took quite a few tries to get the hang of wrangling the long wire and recording in time to catch some vocalizations. Sometimes the dolphins would suddenly change their behavior and squall away at high speeds out of the detection range. Sometimes they were just silent. However sometimes, once the engine was off, the hydrophone was in the water, and the recorder and amplifier were switched on (given the batteries were charged and the SD card was in its slot), the voices that came through my headphones were simply breathtaking. This piece of equipment allowed me to access an underwater world that few people are lucky enough to experience. Listening to their whistles and calls as they communicated with each other and to their buzzes and clicks as they echolocated in search of food, added a whole new dimension to observing their behavior at the surface. It gave me a new appreciation for their complex sociality as well as the impact that ocean noise must have on their daily lives.
This is just a taste of a few of the wonderful experiences I have had this month during my Experiential Learning internship working with Oceans Initiative. I’m sad to leave the dolphins behind as this season comes to a close, but I am looking forward to working with Rob and Erin more this winter to help analyze the acoustic data we have been collecting over the last month for my Keystone thesis project at Quest University.
I have learned so much about the many different aspects that are involved in researching cetaceans. I can’t thank Erin, Rob, and Doug enough for being patient mentors and for making my dream come true by bringing me along to Malcolm Island for their field season. Thank you to Clara for the giggles, the sing-along-life-lessons, and for being such a trooper. Thank you MaryAnn for your generosity, warmth, and fabulous suppers. And finally, thank you to the unsinkable Molly Brown Dog for the slobbery kisses, being the best team mascot, and for always being there to keep my hands warm on the boat.
Laura Bogaard
September 24, 2016
Laura deploying a CPOD — a high-frequency recorder that detects the echolocation clicks of killer whales, dolphins and porpoise.Molly Brown Dog being helpfulDoug searching for dolphins
A lot of the research our charity, Oceans Initiative, conducts is to see how human activities — all of them — affect marine wildlife, both in the Pacific Northwest and around the world. The iconic orca we study illustrate this problem well. According to the latest census by Center for Whale Research, the population is hovering at 84 individuals. The original problem was a live capture fishery for display in aquaria, with all the direct and collateral damage that entailed. But why aren’t they recovering, nearly 40 years after the captures stopped? Regulatory agencies in Canada and the US agree: it’s a combination of lack of prey (Chinook salmon), too much noise, and chemical pollution. Some of these threats are much easier to manage in the real world than others. But are we focusing on the right threats?
In our field, this thorny problem is described as “cumulative impacts of multiple anthropogenic stressors.” Clumsy, right? Our colleague, Dr David Bain, described it better: Which raindrop caused the flood?
It’s really, really hard to predict how wildlife populations will respond to a minefield of too much ocean noise, not enough food and a body full of chemicals. Think about that for a moment. The blubber that whales put on to survive — used by mothers to make milk for their young — is full of toxic chemicals, and the best way for a whale to detox is to transfer those pollutants to their offspring. Not great for the calf. Adult males don’t even have that option. And if you’re honest about the uncertainty in all the steps and how they fit together, your predictions span the entire range from no effect to catastrophic effects.
This approach doesn’t solve the problem, but it helps identify the problem, and the math is easier. For some critically endangered species, policy-makers may not want to allow ANY impact on a population. For healthy, growing populations, our laws allow some impact on marine mammal populations, because humans use the ocean too: for fishing, shipping, recreation, tourism and extracting energy. Our approach gives us a rough, ballpark estimate of what a healthy population can withstand. Then, you can convene a group of scientists, managers and stakeholders to ask how likely it is that the sum total of all current and proposed activities could cause us to be exceeding that threshold.
There are a number of places around the world where this sort of exercise is needed. As we try to ensure whale and dolphin populations recover from the Deepwater Horizon incident, it would be good to look at the cumulative effects of all activities, including seismic surveys, in the Gulf of Mexico. As we discuss opening new parts of the Arctic to oil and gas activities and shipping, we can use this method to test whether all of those activities, together, could affect food security of communities living in the Arctic. As we consider the number of industrial developments for the British Columbia coast — ports, liquefied natural gas terminals, pipelines and tanker traffic proposals — it may be time to consider how all of these factor may affect whale and dolphin populations. Some are doing fine. Others are barely hanging on. Our new tool can give us a starting point for discussion how much is too much.
We loved writing this paper with Dr Christopher Clark (an acoustician at Cornell University), Dr Len Thomas (a statistician at the University of St Andrews), and Prof Philip Hammond (a marine mammal population ecologist at the University of St Andrews). Please check out the #openaccess paper on the website of the journal, Marine Policy:
Gauging allowable harm limits to cumulative, sub-lethal effects of human activities on wildlife: A case-study approach using two whale populations
