The otter spotters

Park uses remote cameras to study elusive animal

Ross Mair
Published on February 9, 2012

John Gosse treads carefully as he makes his way through the woods around Muddy Brook, in Terra Nova National Park.

The slightest noise may scare off his prey.

Gosse is a terrestrial biologist with Parks Canada. His job is to keep watch and gather information on the various animals that call this park their home.

Today he's in search of the elusive otter.

He keeps his voice low as he explains his research and offers up his knowledge on the little critter that's a member of a mustelid family.

"They're fairly secretive. As soon as an otter hears you they dip away or head into the woods. They seem to be easier to see if you're in a kayak or a canoe and being quieter," Parks scientist John Gosse cautioned.

"When you do see them, they usually see you first, and they act differently (than they normally would,)" David Coté another scientist with Parks Canada based in Terra Nova National Park, told the The Packet.

Because of the reclusive and skittish nature of otters, Gosse and Coté have been using motion sensor cameras since 2011, strategically placed throughout the park, to study the animals' behaviour.

"An important thing about otters, is they're a good indicator of ecosystem health because they're top-level predator," Gosse said. "If you have a healthy otter population, that should be a reflection that the lower levels of the ecosystem are also healthy."

From what they've seen and documented from their cameras, the park's otters are not only healthy, but they are exhibiting behavior that would indicate the park is a better place because of their presence.

"One thing that we found, the otters tend to use rub sites, or latrines, that the family group comes to day after day, year after year. These sites seem to be real hotspots of activity, and not just for otters. Eagles, ravens, mink, we've had bears visit there, coyotes and foxes, even moose.

"We think what's bringing these animals to the sites is that when the otters are feeding they're leaving scraps of food behind, as well as their scent, and these other animals are coming in and picking up scraps," said Gosse.

Because these latrine sites are also abundant in "fertilizer," it promotes the growth of vegetation such as mountain ash and dogberry trees. The ash trees make excellent feed for moose, who enjoy nibbling on the limbs and leaves of the hardwoods, while the fruit of the dogberry tree provides a meal for hungry bears.  

Otters are choosy about where to set up these latrines, explained Gosse.

"A lot of these sites seem to be associated with freshwater. You have a little brook coming down, or a pond, and otters need that freshwater to clean their fur. Saltwater will take away some of the water-proofing of the fur, so they have these freshwater pools around to hop in them and splash around; basically to clean themselves and get the salt out of their fur."

Occasionally, and if desperate enough, the otter will take rodents and other small game, but the overwhelming bulk of their diet is provided by the ocean, with flounder, cod, stickleback and trout composing the majority of their catch.

Accodring to the Park's research, and documented in a paper by Cote, otters appear to be very selective when fishing and employ a tactic to ensure there will be meals for years to come.

"It seems otters enhance the nursery habitat for juvenile fish, such as cod. The otters feed close to shore in areas where you get a lot of eel grass and kelp. In that area you get a lot of small fish, and they're in there to escape predation from larger fish, the ones you get further offshore. We think the reason you don't get the large fish coming into the shallow zone, is because you get things like otters, and they'll remove those large fish. In turn those smaller fish get a lot of protection," said Gosse.

He also explained baby cod aren't worth an otter's effort. Developing fish will head into deeper waters, eventually returning to feed on the smaller fish, and the cycle perpetuates itself.

"(Juvenile fish,) they're not fit to go after. An otter is a pretty big animal so they want to maximize the amount of food they get. When they expand energy, it's to take the largest fish they can get. It's a fairly cool ecological role."

Otter trackers

During last week's outing, Gosse carried with him a remote sensor camera, one of 17 the park set up in the area to collect and monitor otter movements.

They also collect scat samples. This helps them determine DNA and the number of animals in the park, which they estimate to be in the neighbourhood of about 75 otters. The laboratory work is done at Memorial University.

Although no otters were spotted on this outing, it provided an excellent opportunity to find out more about the otter and help clarify some of the perceptions surrounding the semi-aquatic mammal.

"(We do this to) appreciate the animal as one of our native species, to recognize that they have an ecological role. An otter is an iconic species of the Boreal Forrest, they're interesting animals and kids in particular are excited when they see an otter, but certainly their ecological role is important, whether it's enhancing fish nurseries or acting as a predator in the environment."

Added  Coté, "A lot of people look at it simplistically, they think that otters eat fish and therefore they're competing with us. Yes, they eat fish, but they're enhancing fish nurseries and the whole concept that otters are competing with us is a bit too simplistic. Otters may not be as bad as you think in terms of negatively impacting fish resources."

Gosse said kayaks and canoes are the best mode of transportation for otter-spotting.

Coté added, "Go out often, you just see them walking along the coast line. In the fall they seem to be spotted a lot more frequently. Sometimes it seems the otters find you."

Follow the link to the video to see the otters and other creatures in Terra Nova National Park.