A Silver Cycle

Michelle Nelson, PhD candidate, Simon Fraser University

Bella Bella Field Station
Spring 2007

The wolf hasn’t smelled us yet. Anxiously pacing the stream bank, he trots forward and back, nose to the ground, eyes on the water, intent on the movement beneath. He’s watching and waiting for the precise moment when he’ll leap, suddenly and skillfully, to emerge with a fresh catch in his teeth. Fins break the surface in every direction as thousands of spawning salmon crowd the mouth the stream struggling to secure their place in the queue as they hold and a wait for the rain that will enable them to push forward and upward.

Salmon attract animals to feed and bring these estuaries to life in the fall. Raucous calls of gulls and ravens fill the air. Hundreds of eagles are perched in trees lining the banks.

Seals and otters swim in to join the feast. Bears drag carcasses into the forest where they can savour the food that will sustain them through the winter. The aromatic leftovers are consumed by other creatures such as tiny winter wrens and tree-dwelling martens.

Integral to the coastal ecosystem, salmon provide an important seasonal food source for a diversity of its wildlife. They have nourished its people for thousands of years. Nutrients from decaying carcasses fertilize trees and plants that give this coast its lush and breathtaking landscape.

Of course, the wolf isn’t thinking about all that. Suddenly, he stiffens. He’s picked up our scent and with a last longing look toward the fish, he retreats to the forest until he’s certain we’ve moved on.

My research is part of a collaborative study between Raincoast and Simon Fraser University that seeks to better understand the effects of the great influx of nutrients that spawning salmon provide to coastal ecosystems in the Great Bear Rainforest.

Young coho salmon spend a year in their natal streams before heading out to sea. With coho as the focal species, my research goal is to illustrate how spawner nutrients affect numbers of emerging coho. How do the number of spawners affect numbers of emerging coho? How do the number of spawners affect the growth and survival rates of young coho?

To answer these questions the coho team works diligently to collect data across a number of watersheds in the Great Bear Rainforest. We assess various streams, many of them small and largely unstudied, in order to evaluate coho populations, food and habitats. We collect hundreds of samples for isotope analysis which can be used to reconstruct the aquatic food web and will help us to better understand the needs of these fish and how they interact with other organisms.

I hope that a greater understanding and appreciation for the complex relationships between salmon and this coast will result from the work of this project and that it will serve to further conservation initiatives on behalf of salmon, the foundation of our coastal ecosystem.

By Michelle Nelson
PhD Candidate,
Simon Fraser University

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