The Invisible Migration

The great journey we never see

By Joseph McDaniel, Summer Conservation Scientist, Northern BC

June 2, 2023

God’s grace can sometimes be invisible to us. We need to look with the eyes of faith in order to see it. 

The waters of Buck Creek and the Upper Bulkley River are high and turbid with sediment as recent rains and melting snow cause a surge in the water levels known as the flood pulse. To the untrained eye, there is nothing in these streams but swift waters and silt. We are rightfully wary of the risk these waters can pose to infrastructure and homes.

I am a newcomer to this watershed. But I know that beneath the swirling of eddies and foaming of rapids there is a journey taking place that is common to nearly all the watersheds in this province. It is called the “invisible migration.”

At this time of year, young salmon fry have emerged from their gravel nurseries. They will cautiously stay hidden underneath rocks and woody debris, remaining close to the margins of the stream channel. In flooded riparian areas, they will move among the shrubs, feeding on a rich diet of invertebrate life. 

In the lower reaches of the watershed, where the Skeena nears the coast, emerging Pink salmon and Chum salmon will migrate to the estuary soon after their emergence from the gravel. In the upper reaches of the watershed, Sockeye fry will migrate to lakes such as Babine Lake and Coho and Chinook fry will remain in their home streams to continue their growth as juveniles. While different populations will have unique life histories, most Sockeye, Coho and Chinook populations will begin their sea-ward migration at this time of year once they have reached approximately one year of age. Steelhead will also participate in this journey. 

The scale of this migration is staggering in its magnitude, measuring in the millions, and mysterious in its seeming invisibility. A seine net may catch hundreds of juvenile salmon on a sampling survey, only to see them apparently disappear back into the waters upon release. 

We also know how increasingly fragile this migration is. Many of the threads of habitat, food supply, water temperature and quality upon which these juvenile salmon populations depend are being strained or severed. A single pollutant spill down a storm drain or erosion event due to poor sediment control can have a harmful impact on a salmon population. 

When you’re crossing a stream, stop and look, and share with others passing by about the life you know is beneath the surface. And if you see that life being threatened by a pollution event, call your local municipality or government agency so that they can respond. 

In this way we can be partners with God’s creation, and support our fellow creatures as they undertake one of the greatest journeys that nature knows. 

Joseph McDaniel will be serving as a Conservation Scientist at A Rocha’s Buck Creek Canfor Hatchery and Nature Centre in Houston BC. 

Conservation in Northern BC

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A Rocha Canada’s Northern BC project works with local environmental organizations, churches, schools, governments and concerned citizens to  protect and enhance biodiversity and ecosystem health within the Wet’zinkwa (Upper Bulkley) watershed.

Conservation in Northern BC