Little truths

Words by Erin Ashe
Photographs by Erin Ashe & Ryan Tidman

We all have our cetacean story – the first moment we discover that these magical beings exist.

Maybe we read about a whale or are lucky enough to see one in the wild. Maybe we see a distant blow on the horizon and that’s it. The philosopher Ralph Waldo Emerson said that, “The stars awaken a certain reverence, because though always present, they are always inaccessible.” This statement could easily be applied to whales and dolphins. My cetacean story involves seeing killer whales when I was four years old. My aunt woke me early one morning to join her, while we listened to the powerful blows of an orca family travelling slowly through the fog in the waters below her clifftop home. After the whales disappeared around the point, my questions began. Who are they? How do they live their lives? What do they eat? Where do they go? This is how my fascination began.

Fifteen years ago, on a whim, I hopped on a float plane from Seattle to the Broughton Archipelago in Canada with Rob Williams, a fellow marine biologist. We took off together and flew high above the waters of the Salish Sea, but low enough to watch a pod of southern resident killer whales making their way to Georgia Strait. We continued northward over Vancouver Island before reaching a remote island only accessible by boat, where Rob had built a cabin. The next day, we set out in his small boat to shop for groceries on the island next door. As I looked to the east, I saw a wall of water that made me think a squall was coming. Rob put my mind at ease by saying, “Cool! Lags!” I didn’t let on that I had no idea what Lags were. I waited with binoculars ready until I could see hundreds of dolphins thundering across the strait. Their sleek grey and white bodies caught air as they porpoised through the water. This motion created the white water I’d mistaken for a squall. As I scoured field guides later, I realised they were Pacific white-sided dolphins (Lagenorhynchus obliquidens, fondly known as lags). That moment of anticipation, discovery, and awe is present each time I encounter Pacific white-sided dolphins.

At a glance, you could tell that the life-history of these dolphins reflects the power that comes from numbers and speed. Travelling in a large group can offer an advantage when detecting clever predators or finding patchily distributed prey, especially in the open ocean. The open ocean is where one expects to find Pacific white-sided dolphins. For years, during the 1970s and 1980s, Pacific white-sided dolphins were the victims of the high-seas drift net fishery that left thousands upon thousands of miles of fine fishing net to drift, unmonitored, and largely unobserved. The intended targets were squid and salmon, but the nets easily entangled dolphins. The practice also separated dolphin mothers and calves, and mortally wounded or drowned hundreds of thousands of Pacific white-sided dolphins before the practice was finally banned by the United Nations in the early 1990s. This was one of the reasons I was surprised to see oceanic dolphins in the inshore waters of British Columbia (BC) in the Broughton Archipelago, where even salty mariners can get lost in the vast, foggy maze of islands and endless, winding fjords. But I had studied Alexandra Morton’s book, Listening to Whales, very carefully and knew that First Nations Middens kept an archaeological record and told their story.

Pacific white-sided dolphins British Columbia Canada
Pacific white-sided dolphins British Columbia Canada leap
Pacific white-sided dolphins British Columbia Canada fin

For thousands of years, Pacific white-sided dolphins have played a vital role in this ecosystem. As I worked on studies of northern and southern resident killer whales, I was struck by a huge contrast. Researchers had been photographing killer whales in the Pacific Northwest since the early 1970s and were able to identify individuals by unique natural markings in their dorsal fins and patterns of the grey-white saddle just behind the fin. Thanks to their devotion to this painstaking task of cataloguing each pod, family, and individual, we now know when the population of killer whales increases or decreases by one individual. But, what about Pacific white-sided dolphins and other cetaceans of the world? How would we know whether human activities like the high-seas drift net fishery tipped the dolphins over the edge into an unsustainable decline toward extinction?

Globally, bycatch in fishing nets is responsible for killing hundreds of thousands of dolphins and small whales, but we don’t read about it in the paper as we do here in the Pacific Northwest each time we lose an orca. But, knowing how many individuals are in a population and whether that population is going up or down is fundamental to protecting biodiversity on this planet. I went to graduate school at the University of St. Andrews to learn the math and statistics required to answer some of these questions. I used Pacific white-sided dolphins to hone my skills, but my aim has always been to apply some of these lessons to conserving small cetaceans in other parts of the world. Alexandra Morton had been collecting photographs of killer whales, but also began a catalogue of dolphin photographs in the 1990s. She shared her catalogue and the benefit of a historical record. I built on that foundation and have added ten years of photo-identification to the non-invasive, long-term ecological study I now lead.

With the cabin as our cost-effective base of operations, we set out in our small boat to add contemporary sightings to this record with photographs. As Alexandra had assured us, the key to building a career in this underfunded field is to put yourself in the path of whales and dolphins, and the rest will fall into place. Before our daughter was born, there was only a fuzzy boundary between fieldwork and our home lives. Between field efforts, I would return to Scotland to continue my studies and turn these photographs into data. Although I’d been doing fieldwork for years, on my first day as officially registered as a PhD student, we witnessed the ecosystem in action. On a misty November morning, we spotted a group of about 500 dolphins feeding in a deep, glacial fjord in the Broughton Archipelago. It was fall, when giant, silvery spheres of herring collect in bait balls. The dolphins have perfected a coordinated dance to corral and exploit this valuable, fatty prey. Herring, we think, explain why the dolphins are here. Although unpredictable in abundance, the local spawning areas and stocks are reliable, or at least they used to be. We set about the task of photographing all 500. When I first began photographing these dolphins, I could fall into the trap of becoming distracted by hundreds of fins breaking the surface of the water. Focus is vital. There is a wonderful word in the Canadian Inuktitut language, called “Puijilittatu,” which means, “He does not know which way to turn because of the many seals he has seen come to surface.” I could relate.

One of the group engaged in a series what seemed like hundreds of leaps, each ending with a thunderous splash on its side. In an instant, the dolphins disappeared underwater. I glanced over my shoulder to see a giant killer whale fly through the air, arc, and dive into the water. The dolphins fled. I could see now that it was a group of five killer whales. Somehow, they had hidden in the propeller wash of our boat. With two killer whale researchers on board, we’d simply missed more than 10 tonnes of orca in our wake. The whales herded a group of dolphins nimbly, neatly, and expertly into a small cul-de-sac of a bay. The largest male attacked from below and launched a panicked dolphin into the air, and then dove back on top of the dolphin, delivering a final blow. I could subtract one dolphin from my population estimate. This dynamic inspired another line of research and exploration. How do these dolphins find food and have calves, but avoid getting eaten? Were they as surprised as we were by the killer whales? Does the presence of killer whales cause stress or drive changes in their daily activities? Our photographs show a fraction of the scars dolphins bear from killer whale teeth that reveals a sizeable fraction of dolphins actually survive these attacks. Interviews with people who have spent a lot of time with whales and dolphins have taught me that in fact, killer whales are only successful about half the time they attack Pacific white-sided dolphins. Oddly enough, Pacific white-sided dolphins spend a fair amount of time with the sympatric, resident, or exclusively fish-eating killer whales that also call these waters home. Although it appears the dolphins are a nuisance to fish-eating killer whales, I believe these interactions give dolphins the opportunity to literally size up their predators – the mammal-eating, or Bigg’s killer whales.

I started my PhD expecting, to be honest, to find that fisheries interactions were impacting the dolphins I study. I learned quickly that the primal quests of finding food and avoiding predators were far larger drivers than humans of Pacific white-sided dolphin ecology. Countless years of evolutionary forces have shaped cetacean physiology and behaviour, and killer whale predation pressure is a significant force. Human activities are an important factor in the daily lives of Pacific white-sided dolphins, but they seem unlikely to be the most important factor. We know that many small cetaceans respond to human activities and disturbance such as ocean noise, but it is impossible to forget that these disturbances are taking place in a predator-prey framework.

Pacific white-sided dolphins British Columbia Canada
Pacific white-sided dolphins British Columbia Canada
Pacific white-sided dolphins British Columbia Canada

Our work is examining the relationships among herring, dolphins, and orca in more detail, in an ecosystem where the threat of predation is ever-present for dolphins. Our long-term photo-identification study is allowing us to build upon decades of abundance and survival estimates to place natural and anthropogenic factors into population dynamics models and rank research priorities. We are assessing dolphin health by collecting their exhaled breath on agar petri dish plates. This effort will help advance our understanding of exposure to pathogens – funguses, bacteria, and viruses – in free-living dolphins and their environment. This may give us an early warning if a viral outbreak threatens survival of the critically endangered southern resident killer whales. Although bycatch is no longer considered a major threat to Pacific white-sided dolphins in my study area, rapid assessment and mitigation remains a research priority for cetaceans globally. We are testing pingers, or devices that emit alarm sounds to help deter dolphins from fishing nets, so they can be applied in the high-seas fisheries that first inspired my work on this species. Over the years, this exploration has revealed what the pioneering cetacean researcher, Dr Ken Norris, referred to as the need to discover “little truths” about poorly studied species. These little truths can be synthesised over time, as new information becomes available. Together, this can inform conservation and protection for cetaceans whose vast, offshore habitats may make them inaccessible to study, but still exposed to impacts from fisheries, oil and gas exploration, and naval sonar exercises.

Some of these little truths have led to big changes. It turns out they are not lags at all, but sags.  Shortly after our daughter was born, I convened an international workshop with scientists from around the globe to reassess the Lagenorhynchus genus. As we shared our little truths about this genus, we realised that a taxonomic revision of the genus was in order. The workshop findings spurred an interdisciplinary effort with geneticists and taxonomists to reclassify the genus. It turns out that my study animal has been called by the wrong name for more than a century, and we tentatively proposed resurrecting the genus name, Sagmatias, until we can collect a few more genetic samples from the even lesser known hourglass dolphin in Antarctica to resolve this branch of the cetacean evolutionary tree.

More than a decade after Rob and I were married, we’ve named hundreds of individual dolphins in our study area. Catalysing efforts to rename the genus, Sagmatias, was far more satisfying. Now, when I spot the dolphins, I say slyly to my husband, “Cool! Sags!” As we bring our daughter into the field each season, I’m reminded that the conservation ethic that inspired the study still motivates my work. My hope and aim now is to do what I can to ensure that, like the stars, Pacific white-sided dolphins are always present on our planet.

Photographs by Erin Ashe & Ryan Tidman