Katie Kuker, off the reefs of Nuchatlitz, northwest coast of Vancouver Island

UBC Reports | Vol. 52 | No. 9 | Sep. 12, 2006

Following the B.C. Sea Otter

It’s 6 a.m. when we pull up to a gravel beach on a small island on the northwest coast of Vancouver Island. My research assistant Alyssa and I grab our spotting scope, binoculars, camera and notebook and hop out of the inflatable boat, scrambling along the beach to a high observation point we refer to as the ‘grassy knoll.’ From this vantage point we can observe sea otters among the islands and reefs of Nuchatlitz.  Meanwhile Brock, my other assistant, drives the boat around the island to set anchor and prepare for the days experiments.

Killer whales are the top predators in the ocean, known to take down even the largest animal, the blue whale. It is thought that killer whales are causing a huge sea otter population decline in the Aleutian Islands in Alaska, but these whales do not appear to be eating otters in B.C.  As part of my research, I am attempting to address this issue by comparing the behaviour of sea otters in B.C. and Alaska to see if they respond to killer whales differently. We can simulate the presence of killer whales by playing recordings of vocalizations under water, ‘blow’ sounds above water and by displaying a dorsal fin decoy.

Today we are conducting experiments with blow playbacks. I count almost 200 male sea otters resting and grooming in a ‘raft’ (all bunched together in a kelp bed) about 700 metres offshore in their usual location. For the next two hours we wait…. and no individuals have set out for their daily foraging excursion.

But we definitely are not bored. A bald eagle soars overhead and swoops down not four feet above our heads, followed by a juvenile, perhaps learning how to hunt. We see whale blows out in the distance -- a gray whale foraging along the reef looking for benthic prey. A harbour seal curiously pokes its head up from the kelp to look around at its surroundings while a steller sea lion quickly swims by in search of prey.

“OTTER!” I hear Brock shouting through the walkie-talkie from the boat. Alyssa and I quickly find the otter, swimming on its own in our direction. When the otter is about 200 metres away from the boat, he begins to forage in the kelp, constantly surfacing with large clams in his paws, quickly eating them at the surface, and diving down again, only to surface once more with another clam. After recording his behaviour for two minutes, we tell Brock to start the playback.

We are shocked by the variety of reactions the otters exhibit when exposed to the various experimental cues. Some otters change their behaviour while others do not even acknowledge them. Since this is my first field season out of many more to come, it is too early to conclude anything to date -- until I investigate the behaviours of the sea otters in Alaska.

When we return home to our cozy little cabin, we prepare for a dinner with the community members on the island. They all welcome us with a big turkey dinner and are anxious to hear about our observations. The unique ecosystem and the otters have been very attractive to kayakers in recent years and humans could potentially disturb the sea otters and their rafts. My hope is that the local residents of the island can share what we’ve learned about sea otter behaviour with future park visitors to ensure that the otters are left undisturbed.