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Understanding Seals – A Scientist and Artist in One of the Last Wild Places on Earth
- Published on Monday, 14 November 2016 09:13
- Jenny Woodman
- 0 Comments
Damian Lidgard is a scientist and artist who spends eight weeks each year on a remote barrier island studying and photographing grey seals for Canada’s Ocean Tracking Network. Part Two of Three. Click here for Part One and Part Three of the series.
There is something in their dog-like eyes that draws an onlooker in, sharing, for a brief moment, the illusion of understanding as they stare down the camera lens. Perhaps these creatures offer a reminder to the viewer that we are all just animals seeking to satisfy desires for food and relative safety. But, humans cannot really imagine the lives of seals slipping into the water to swim and forage any more than they can imagine our world, draped in cloth and machinery – yet still we seek to know them.
Grey seals, or Halichoerus grypus, line the beaches of Sable Island, a remote barrier island 100 km southeast of Halifax, Nova Scotia. With 75,000 pups born last year, researchers at the Ocean Tracking Network (OTN) estimate that the seal population is several hundred thousand strong. The grey seals are large carnivorous marine mammals, members of the pinniped, or “flipper-footed,” suborder and Phocidae family of true seals; they are considered to be apex predators in the marine food chain.
Damian Lidgard is a zoologist, photographer and postdoctoral fellow at OTN; he describes the difficulties in knowing these ever-present, but elusive creatures. While on land, scientists can observe their breeding and molting behaviors, but seals spend a tremendous amount of time out of sight, underwater. A seal can disappear for weeks at a time, traveling, sleeping on the ocean floor, and foraging for food. Until recently, scientists knew little about their underwater lives. “Our understanding of their behavior grows as new technologies appear,” explains Lidgard.
OTN is a Canadian organization operating out of Dalhousie University. They, along with partner organizations like NASA and Australia’s Institute for Marine and Antarctic Studies, use technology to study marine life, including endangered, keystone and commercially important species, around the world. The goal of marine tracking is to provide data that support sustainable ocean and fisheries management. They use electronic tracking devices, gliders, acoustic receivers, and the Argos satellite system for satellite uplinks to platforms distributed around the globe.
In September 2016, Lidgard traveled to Sable Island to tag grey seals as part of OTN’s efforts to understand and monitor the relationship between these predators and the Scotian Shelf ecosystem. He has made this trip twice a year since 1996; his visits last for two to six weeks, depending on whether the seals are breeding or molting.
The male grey seal can weigh more than 300 kilograms and be quite aggressive, so Lidgard and his colleagues sedate the animals before outfitting them with an accelerometer, GPS tracker, acoustic transceiver, and camera. The devices are glued to nylon netting, which is then glued to the seals’ fur. Later, the researchers retrieve their devices. When the animal returns to the beach to molt, the netting comes off with the molted fur. Researchers observe the seals and their interactions with each other, and the animals appear unfazed by the devices, Lidgard says.
Once tagged, the seals act as bioprobes, analogous to smart watches and phones that track a person’s movement, daily steps, and related conditions. The technology OTN uses allows scientists to measure animals’ movements and interactions with other tagged creatures as well as ocean conditions such as temperature and light intensity.
Lidgard is intrigued by the seals’ ability to navigate gracefully on land as well as at great depths and extremely cold temperatures in marine environments. “To me, they are fascinating animals because of their adaptations,” he said. He’s kept coming back to the island year after year, seeking to answer questions about these creatures. In particular, Lidgard said he believes there is a lack of evidence to support popular assumptions about seals and threats they may pose to fish stocks and commercial fishing, particularly Atlantic cod.
Lidgard explains that since fish mortalities largely come from other fish, attributing declining cod stocks to seal predation may be a mistaken view, which ignores the larger picture. There could be reason to suspect that seals play a valuable role in the ecosytems with which they interact.
Recent ecological studies have looked at the transfer of marine nutrients to previously nutrient-poor sand via the seals on Sable Island. The researchers believe the island’s genetically unique wild horse population is feasting on enriched marram grass, because 200,000 seals release a great deal of nitrogen into the environment, which fertilizes the grass. The research could illuminate new avenues for protecting an endangered population of horses.
He explains: “People have a veil; they have a curtain that stops them from seeing these animals for what they are and they are totally focused on the ill-effects that they think that these animals are having.” It turns out that there is little love lost between fishers and seals.
By monitoring how the seal moves its head, compared with GPS data from seals and tagged cod, Lidgard sees many instances where the cod are present, but not detected by the seals. When the cod are detected, movements associated with feeding are often not present.
However, the researcher cautions that he needs more data to make real statements about whether or not seals are eating cod. “There are some data that show that grey seals do eat cod, but I don’t think it’s a large portion of their diet,” Lidgard said. Diets vary greatly from one individual seal to another. He adds that seals tend to eat what is abundant in their environment, and cod is not abundant; these animals tend to eat large quantities of fatty fish like herring and redfish.
Great amounts of fat are a big part of a healthy seal’s life. When a female seal comes on shore to nurse newborn pups, who typically weigh about 14 kg at birth, she does not eat while on land. The pups grow to up to 75 kg in short span of time, by feeding four times a day. “She arrives extremely fat and extremely rotund; when she leaves after three week, she’s skinny as anything,” Lidgard said. “You can see her spine, her ribs. It’s a massive transfer of energy from mum into her pup. It’s amazing.”
The researchers recently added cameras to the seal monitoring equipment, which Lidgard hopes will reduce the need to make assumptions about things they cannot witness firsthand. In addition to his research with OTN, Lidgard has photographed Sable Island and its inhabitants for quite some time, so video felt like a natural way to expand his observations of the seals. In September, a film crew joined the researchers to record the scientific activities, and filmed Lidgard photographing the seals. He added, “They liked the idea that there is this science and art going on at the same time and how one can inform the other.”
“I’m a behaviorist; that’s where my interest is,” Lidgard says. “Looking at animals though the camera, I spend more time observing them. It makes me a lot more attentive in the field. I’m noticing more about the animal just because I am, in that way, engaged.”
Getting to Sable Island is not easy. One can travel by boat, helicopter, or a Britten-Norman Islander equipped with special landing gear to land safely on sand. There are no regular flights, only charters, and the trip takes about 1.5 hours by air, but travel is often delayed by weather and rough conditions – factors and obstacles that contribute to the untouched nature of the place.
This barrier island isn’t much more than a sand bar. It is 42 km long and 1.4 km wide. Science Writer Kate Sheridan explains, “Barrier islands are traditionally ephemeral places. Little more than towers of sand piled high in the ocean, these islands, which are often long and narrow, are constantly shaped and reshaped by battering waves and whipping winds.”
Sand and beach grasses, dotted with goldenrod, hawkweed, and bayberry, form the landscape. It is so desolate that it is difficult to imagine much of anything calling the little strip of sand home, but small freshwater ponds make the island habitable for wild horses, migrating birds, wildlife, and Lidgard’s grey seals.
When he started going to Sable Island 20 years ago, it was overwhelming. The constant threat of storms, being cut off in an isolated area by high tide, and wild animals trying to bite his feet took some getting used to. Now, he is acclimated to the unusual terrain and looks forward to returning.
“I love going out there because if its wildness – it’s truly a wild place,” Lidgard said. “There is very little sense that man has impacted it. You’re totally open to the weather and you’ve got all of these wild animals all around you and the sea is right there. You never get away from the sea because it is right on your doorstep.”
Most of the year, there are only four or five people living there to run the weather station, research the wildlife, and tend to the small outpost. The wildness of the place cannot be understated. The landscape changes daily, and features used for navigation can disappear in a matter of weeks.
“Sable Island is extremely unique place and there’s nothing quite like it,” Lidgard said. “The fact that it is an island totally made out of sands and yet it can exist in the Atlantic Ocean is totally bizarre. It only exists because of these currents that operate around the island that are shifting sands from one place to another.”
Jenny Woodman is a science writer and the Writing Club coordinator for IEEE Earthzine. Follow her on Twitter @JennyWoodman