Chasing Dolphins

Last month, I travelled to Bethany Beach, Delaware, for my extended family’s annual reunion. We’ve been spending a week at the beach every year for my entire lifetime, and every year has been marked by much-loved traditions that carry the unmistakable tang of the Mid-Atlantic coastal culture: sunbathing and boogie-boarding, lifeguard-gazing (I mean, hey…) and books on the beach, family togetherness and chats and salt and sand everywhere. Every year, too, my dad wrestles a trusty (and increasingly-battered) sea kayak to the top of the car and brings it to Bethany for us to use.

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The sea kayak in one of its finest moments.

 

And every day, we launch the kayak into the waves for a morning or evening of sea paddling and dolphin chasing. Because the other reliable part of this Mid-Atlantic beach scene is the appearance of bottlenose dolphins. There’s a pod of dolphins that cruise along the beach as they hunt, eliciting coos from beach bums and furious paddling from kayakers hoping for a closer look.

This summer, that long-loved pattern hadn’t changed. And as my parents and sisters and I perched in the kayak with dorsal fins slicing the water around us, I was reminded of the dolphins I’d seen up close in a whole other hemisphere…

Last year, I was in New Zealand during the family reunion. And though I’d been fortunate enough to see many family members over the course of the year, the dates of the reunion didn’t approach without a pang. I missed my family, the Mid-Atlantic-coast, the chance to chase dolphins. But just a few weeks before the scheduled reunion, I met a group of scientists at the New Zealand-Australia Marine Sciences Conference. They were a Dunedin-based crew, studying marine mammals everywhere from the sub-Antarctic islands to Auckland. And they were friendly, to boot. Sitting down with them at the conference dinner led to a rich conversation, and eventually an invitation to come to their field site on Banks Peninsula to spend a few days helping out and learning about their research. The date? Same as the start of my family reunion, many thousands of miles away. The research subject? Dolphins—specifically, the tiny, increasingly threatened Hector’s dolphin.

How could I say no?

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A few weeks later I packed an overnight bag and made the drive out from Christchurch to Banks Peninsula. The peninsula is an old megavolcano, which erupted about 10 million years ago and left a stub of land convoluted with bays and inlets. These waterways offer prime habitat for the Hector’s dolphins—in Maori, often called Tutumairekurai or Upokohue; in science, Cephalorhynchus hectori. The Hector’s dolphin is a funky little cetacean: just about four feet long, black on top and white below, sporting a dorsal fin shaped like a Mickey-Mouse ear. These dolphins are found only off the coast of New Zealand, and are one of the more endangered dolphin species on the planet.

Studying the conservation of Hector’s dolphins is what brought my host, Jesu Valdes, to New Zealand in the first place. She’s one of those rare people who has followed up her love for dolphins with dedicating her life to their study and protection. That dedication brought her from Chile to a PhD program at New Zealand’s University of Otago, and from there on to seasonal research of Hector’s dolphins off the coast of Banks Peninsula.

Arriving on the peninsula bright and early on a Thursday morning last July, I met Jesu and her best friend and labmate David as they were packing up for a day of field work. Together, we loaded a car with field equipment and datasheets and drove out along the bumpy, dusty, sheep-bordered roads of Banks Peninsula to a site overlooking Little Pigeon Bay.

 

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Jesu and David setting up the theodolite.

That day, our work was land-based. Our task was to spot and track dolphins moving into and out of the bay. To help in tracking the dolphins, we set up a theodolite—a surveying instrument that measures the precise location of a point in its viewfinder. With the theodolite set up, the three of us perched on the hillside, eyes and binoculars glued to the water, scanning for the tiny dorsal fin of a Hector’s dolphin.

…and we waited.

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Scanning for dolphins.

This time provided a good opportunity to ask Jesu about her project. What exactly was she trying to learn? When I asked, she motioned to the water just below where we sat. Along the edge of the bay, sets of seven long lines were moored in the water, held in place and marked by buoys.

Those lines were a mussel farm, Jesu explained. The ropes are seeded with baby mussels, then left to grow to a harvestable size out in the ocean. Once the mussels are large enough, farmers scrape them from the lines and bring them to shore to sell for direct consumption or mussel products.

Mussel farming is new to Banks’ Peninsula, and Jesu’s research centers around how this new venture in aquaculture will impact the population of Hector’s dolphins in the area. One of the major overall threats to Hector’s dolphins, as well as many other dolphin species, is human fishing. Dolphins can be struck by fishing vessels, entangled in gill nets, or hauled up on drag nets, and oftentimes don’t survive these encounters with human fishing gear. A major focus of the Hector’s dolphin conservation plan has been to reduce the number of encounters between dolphins and commercial and recreational fishing. Around Banks Peninsula, many conservation efforts have come about thanks to the NZ Whale and Dolphin Trust, which has been working in the area for decades. They’ve helped bring about the creation (in 1988) and then extension (in 2008) of the Banks Peninsula Marine Mammal Sanctuary was created (in 1988) and then extended (in 2008), which limits fishing and net-setting in the coastal areas Hector’s dolphins prefer to use in the summer season (in the winter, they move offshore and out of the current bounds of the sanctuary). Recently, local Hector’s populations have been on the rise, and the limitation of fishing gear is thought to be a driving cause of that increase.

Should mussel farms be similarly limited in an effort to protect Hector’s dolphins? It’s true that these farms rely on lines and gear that can cause dolphin entanglement, and the movement of boats around them could lead to dolphin-vessel strikes. There could be other threats related to aquaculture, too: mussels could increase nutrient levels in Banks Peninsula bays, which could result in algal blooms and fish die-offs that would hamper dolphin food sources. But on the other hand, mussel aquaculture might not cause problems for dolphins at all. It’s possible, in fact, that they’ll have a positive impact, attracting schools of fish that provide an easy food source for the dolphins. Globally, research into the interaction between shellfish farming and dolphin populations is just taking off. Jesu’s research will have an important role to play in advancing that field, and answering the question of how to balance dolphins and aquaculture in Banks Peninsula.

As Jesu and David explained this situation to me, we kept our eyes fixed on the bay. As the afternoon wore on, the wind picked up and whitecaps bloomed across the bay. Rough water made what was already a difficult job—picking out Hector’s tiny dorsal fins out from above—nearly impossible. Eventually, we decided to call it quits for the day. We packed up the theodolite, reloaded the van, and returned to the house, with a clear weather forecast and high hopes for dolphin sightings the next day.

When we got set up on our hillside the next morning, those hopes were fulfilled early—a dolphin! Its dorsal fin was tiny, but we kept eyes on it, and Jesu jumped to the theodolite to center the dolphin in its viewfinder. We began tracking it as it moved across the bay. As we watched, the dolphin surfaced right between the mussel lines, cruising along the lanes created by the buoy-held ropes.

“So they’re definitely interacting with the mussel farm,” Jesu said, jotting down notes as the dolphin moved out of range of the theodolite. “It could be that there are schools of fish hanging out around the lines, and that’s attractive to this dolphin. Later this year I’ll be putting out fish traps in the area to see if that’s the case.”

Eventually, we lost sight of the dolphin as it left the bay. The day’s excitement wasn’t over, though—a few minutes later, a working boat motored into the bay and idled by the mussel lines. I watched, fascinated, as the workers hauled up buoys from various points along the lines.

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Mussel boat in action.

I asked Jesu about her interactions with mussel farmers—after all, it’s a small-town kind of peninsula, and most of the farmers live nearby. She had informed the farmers of her research plans, and I couldn’t help but wonder how the farmers view dolphin researchers. In the Pacific and Atlantic alike, a common concern is that aquaculture might have negative impacts on protected species, resulting in a limitation of a local industry. At the same time, these protected species are often highly valued, providing tourism incentives as well as sources of identity and pride. That’s certainly the case in Banks Peninsula, and leaves the question of how mussel farms and Hector’s dolphins will share the bays a bit murky at this point. What’s certain, though, is that more research will be needed in order to make sure conversations about the future of aquaculture are moored in reliable data.

At the end of that day, I packed up and headed back to Christchurch. A few months later, I would return for another day of research, featuring an encounter with a research vessel named Grampus, a massive toothy sea eel, and this delightful moment just a few feet from a Hector’s dolphin.

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Mussel lines– the view from Grampus.

Jesu’s work is now in its second full year. Those early trips to perch above the bay and track single dolphins have been supplemented by many more hours spent in the field and the lab, collecting data point after data point with the help of research assistants from all over the world. At this point, I can’t comment on the impact of mussel farms on Banks Peninsula Hector’s dolphins—but I’ll be interested to see the findings as Jesu’s PhD wends its way (quickly!) to a close.

And until then, I’m crossing my fingers to hang with more dolphins and more dolphin chasers on any side of the globe.

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The author, the sea kayak, the Atlantic Ocean at about 38 degrees north.
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