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
In August, part of our team traveled to the Broughton Archipelago off the coast of northern Vancouver Island to continue our long-term study on Pacific white-sided dolphins. This study is multi-faceted. We are studying the health of the population by taking dorsal fin photos for statistical analysis, but we are also studying the health of individuals by looking for pathogens in exhaled breath. We’ve just celebrated the 10th anniversary of this study, but we made a few changes along the way. This year, with the help of Alimosphere, we were able to look at dolphin pods we encountered from a new perspective through the use of Unmanned Aerial Systems (UAS), also known as drones.
Drone footage collected under permit, by Alicia Amerson.
R/V Wishart
This year, we are sponsoring our research associate, Natalie Mastick, to start an exciting PhD project in marine parasite ecology. As she explains in a recent blog post, taking photos of dorsal fins is a non-invasive way to study the population that allows us to identify individuals that we can use as statistical samples in models to estimate survival rates, and population size and trends. High-resolution dorsal fin photographs show us distinguishable details such as nicks, scars, and markings that help us to recognize individuals from year to year. The Pacific white-sided dolphin study launched by our co-founder, Dr Erin Ashe, has involved taking, processing and matching dorsal fin photos to previous catalogues since 2007. Some individuals have been seen in the study area since the 1990s, and we have seen one pair of dolphins together on two occasions 17 years apart.
Laurel Yruretagoyena, Oceans Initiative research assistant, aiding Dr Erin Ashe in taking dorsal fin photos for her long-term photo ID study. Look closely, like deckhand Molly Brown is doing, and you’ll see some dorsal fins in the distance! Photo credit: Laura Bogaard, 2018.
As a continuation of a study started by Erin in 2015, we also spent much of our time collecting exhaled breath samples from these dolphins. We collect breath samples by positioning a long pole with a petri dish attached to one end over a dolphin as it surfaces and exhales. This is a tricky activity that involves a knowledge of dolphin surfacing patterns, careful boat handling, precise timing, and skillful maneuvering on the bow of the boat. Despite the difficulty, our team was able to collect many breath samples that we will use to assess the pathogens (e.g., viruses, bacteria and fungi) this population has been exposed to. Ultimately, we aim to let the health of the dolphins tell us something about the health of their environment. Understanding how pollutants impact marine mammals and their habitat is essential to informing recovery efforts and monitoring ecosystem health.
A beautiful crisp morning spent with energetic Pacific white-sided dolphins off Vancouver Island. Photo credit: Dr Erin Ashe, 2018.
Next year, we are hoping to invite Alicia Amerson from Alimosphere to the Pacific Northwest to join us in the field again for a workshop on using UAS for noninvasive marine mammal research. We aim to offer this opportunity to other women in marine mammal science, and to our entire staff. We hope this will provide us with a new tool for collecting breath samples in the future, in a continuation of our efforts to use minimally invasive field research techniques. As we close out our field season, we are so thankful for the support we have received to do this important work.
This summer, from mid-July to the end of September, we studied southern resident killer whale behavior under varying levels of boat and ship traffic. (This is an extension of our 2017 field season with OrcaSound). The Port of Vancouver has asked ships to slow down to less than 11 knots as they transit Haro Strait. Reducing ship speed can reduce shipping noise underwater, but slower speeds mean those ships take longer to transit the area. Working with Port of Vancouver and SMRU Consulting, we are exploring how whales navigate that trade-off between noise level and duration of exposure.
Do the whales find more salmon if they are exposed to a little bit of noise for long periods of time? Or is it better to get the noise over with quickly?
Reducing noise is especially important because endangered southern resident killer whales (SRKW) feed in Haro Strait in the summer, and our work has shown that vessel noise disrupts killer whale foraging. While missing one meal might not seem like it would have long-lasting or population-level effects, Haro Strait is a noisy place, which may result cumulatively in many lost meals for the killer whales. We had our team on the western hillsides of San Juan Island all summer to track killer whales in an effort to find out if and how their behavior changes with the slower, quieter ships.
A ship transits Haro Strait by a family of southern resident killer whales. (PC Toby Hall). The theodolite crosshairs allow us to convert horizontal and vertical angles to estimates of latitude and longitude, knowing the cliff height.
To track these whales, we used an instrument called a theodolite. You may have seen them on construction sites or traffic surveys. A theodolite has a telescopic lens that we use to track killer whale movement. After setting a constant reference point, the theodolite can determine the angle between the reference point and the whale we’re looking at. It gets the vertical angle from a gravity-referenced level vector. A computer connected to the theodolite can use those two angles (along with the precise location and elevation of the theodolite) to estimate distances and fixed positions of objects on the ocean’s surface (whales, ships, etc). Your geometry teacher was right—this math does have real-world applications. And we can get all of this fine-scale information noninvasively, without another research boat confounding the effect we are trying to measure. This year, the developer of Pythagoras software generously shared code to let us integrate extremely high-resolution AIS data on the movement of ships, so we could automagically collect precise and accurate data on the ships, while having our expert observers concentrate on measuring the whales’ behavior.
In 2017, the killer whales were worryingly absent from the islands much of the summer, which left us with a small sample size. In fact, for the month of August 2017, the SRKWs were nowhere to be found. This year’s longer field season produced much more data. There were 29 days with whales present around San Juan Island. We had tracking stations set up in three locations along the west side of San Juan Island: County Park, Hannah Heights, and Cattle Point, which allowed us to get close to continuous tracks along Haro Strait. We are excited to analyze the data, which should allow us to determine more about killer whale behavior in the presence of these slower ships.
Video credit: Toby Hall
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This work felt profoundly important this year, in a season riddled with heartbreaking news about the endangered southern residents. J35’s calf died shortly after being born, and the mother mourned the loss of her offspring by pushing around the carcass for 17 days. J50, the youngest individual in the southern resident population, was found to be critically malnourished. NOAA launched the first attempt to supplement a southern resident killer whale’s diet with additional fish. Unfortunately she has not been seen since September 7 and is presumed dead. It is abundantly clear than additional conservation effort is needed, and our team worked hard to make this field season count, both in the field and on the Southern Resident Killer Whale Task Force.
This work wouldn’t have been possible without a super pod of a team. The Oceans Initiative team was led by Erin and Rob, and consisted of our employees Laurel Yruretagoyena, Natalie Mastick, and Laura Bogaard, as well as Toby Hall, Sarah Colosimo, Jess and Chris Newley, and Elizabeth Robinson, who provided additional field support.
Thank you, as always, for supporting our efforts to keep orca habitat clean, quiet, and full of salmon.
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.
Guest post from our newest team member, Natalie Mastick
“I look at pictures of dolphins all day,” is my most common answer when asked what I do for work.
This dolphin has a well-marked dorsal fin, which we will match against thousands of photographs in our database. This photo was taken under research permit with a telephoto lens and cropped.
It’s an over-simplified statement, albeit accurate, and it usually leads to many follow-up questions. The most frequent being “Why?” That’s a fair question. I then proceed to explain how by looking at photos of the dorsal fins of dolphins, I can identify individuals, which can be used in calculating population estimates and survival rates. I am usually surprised by the awe that this explanation inspires, as I am somewhat numb to the task after several months of photo analysis. “You can really tell dolphins apart like that?” They have a point; photo-identification is quite remarkable when you think about it.
Photo-identification (photo-ID for short) is a non-invasive way to study marine mammal populations. It’s been used for both cetaceans (dolphins and whales) and pinnipeds (seals and sea lions), and requires a high-resolution photo of each individual. Photo-ID is an effective way to determine individuals based on coloration, markings, scars, fin shape, nicks and notches. For humpback whales, the underside of the fluke is the most recognizable feature, which is can be photographed as the whale dives. For dolphins, one of the most recognizable features is an individual’s dorsal fin, visible as the dolphin breathes at the surface.
I have worked on several projects that use photo-ID, including a long-term study of bottlenose dolphins in Florida, humpback whale population analysis in Antarctica, and currently, a long-term study of Pacific white-sided dolphins in British Columbia with Oceans Initiative. To accomplish this work takes three major steps: photographing wild dolphins, processing the photos, and then looking for matches between the photos.
Oceans Initiative has been taking photos of these dolphins since 2007, which is not an easy feat. Pacific white-sided dolphin are fast and can often travel in large pods of hundreds of animals. Erin, Rob, and their dedicated field team have a ton of experience taking photos of these animals, which provided me with a hearty collection of over 10,000 photos to process. One by one, I went through and determined the quality of each photo. Obviously when photographing hundreds of dolphins quickly surfacing and diving, not every photo will be useable for a photo-ID catalog. I found the photos in which fins were in focus, parallel with the camera, and mostly visible (not partly submerged or covered by water or other dolphins) and then looked carefully at each fin to determine its distinctiveness.
It never ceases to amaze me how different dolphin fins can look. A dolphin can have a single little notch at the base of its fin that makes it completely distinct from the rest of the dolphins seen that day. The combination of scarring, nicks from other dolphins, entanglements, killer whales, and normal wear and tear provide an endless permutation of unique fins. I visually assessed each high-quality photo and determined if the fin was not distinctive, somewhat distinctive by temporary marking or discoloration, moderately distinctive, or highly distinctive. Moderately and highly distinctive fins can be used to identify an individual over longer temporal scales.
Once the fins were scored for distinctiveness, it was then my job to match them to other fins within that encounter, and lastly between encounters from that season. When matching between a single encounter, it’s a lot like a game of memory. You know you’ve seen that fin before, you just need to remember where in order to match them. Once the fins are matched within an encounter, I compile a “best of” folder with all of the identifiable individuals observed in that area to match to the other encounters.
When you include the variable of time, then it becomes more like a game of 6 differences, in which you need to spot what’s changed in a fin over time. Except instead of having two fins that you know are just slightly different versions of the same fin that you’re comparing side-by-side, you need to look through the entire catalog to determine if a fin has actually changed since last identified or if it’s a new individual. Though that’s a fun challenge, it is unlikely that a fin changes much over the course of a few weeks, which means matching fins across encounters is a little easier than across years.
To match fins across encounters, I compile all of the moderately and highly distinctive fins from each encounter and look for individuals seen more than once. The 2016 field season provided over 1000 identifiable photos, which were then compared to each other to determine if there were matches. This is where your imagination comes into play. Looking at these fins enough, you start to see shapes in the nicks and notches and fin shape. There was a fin with a distinctive nick towards the top that looked like the profile of a person yelling. There was another that looked remarkably like a bicep. There was one photo in which a fin caught the light just right and looked like it was reflecting back the shape of a storm trooper.
Reading that back sounds like I’ve kind of lost it. Looking at fins enough might do that to you! But overall, being able to put a minimum number to the dolphins seen last season (think about all the dolphins we couldn’t photograph and the fins that weren’t distinctive enough to match!) is incredibly rewarding, and completing each step of the processing myself was oddly satisfying. I’m hoping we can get a comparable number of photos in 2017, and look forward to seeing some familiar fins in the field.
