Naturespeak 

Kokanee Salmon ( Oncorhynchus nerka )

By Veronica Sommerville,

Whistler Fish Stewardship Group

Kokanee is a native word meaning "red fish." One glance over the Valley Trail bridge at the bottom of Lorimer Road proves that it is an appropriate name indeed. In the shallow, flowing water, males are dressed to kill in their beautiful red coats while the ladies are a little less showy, but blushing nonetheless.

Kokanee salmon belong to the same species as sockeye salmon. Some 10,000 years ago, during the last ice age, anadromous, or ocean-run sockeye salmon migrated into the Whistler valley. Some millennia later, access to the ocean was blocked. But those trapped sockeye prevailed, forming what is today our distinguished kokanee salmon population. This implies that Whistler kokanee are more closely related to the sockeye salmon in the Lillooet River than to kokanee elsewhere.

Kokanee become mature enough to spawn in three to four years, but a late bloomer is not uncommon at five years. Upon maturity, kokanee experience wondrous changes. They turn red over most of their body, and the male develops a hooked jaw and a slightly humped back. The dieting begins as both males and females stop eating. Body mass, including scales, is converted into energy for migration and spawning.

Nests, or redds, are built by the female violently flipping her tail to move gravel. Instead of helping her, the pesky males court the female and aggressively ward off other eligible males. She permits a male to join her in the redd when she is ready. The female harbours between 300 and 2,000 eggs, which she will distribute in two or three redds. A quick shake and a little quiver, and the eggs and sperm are simultaneously released into the crevices in the gravel. Before moving on to the next redd, and the next male, she gently covers the eggs with gravel. Alas, both adults will die within days of this majestic event.

The eggs develop over the winter and hatch into tiny fish called alevin in February. They are self sufficient, feeding off a large yolk sac until they emerge as fry from the gravel in early spring. The small fry ride the waves of the spring freshet to the lake, where they will gorge on delicious plankton and aquatic invertebrates. Four years later, and up to 5 pounds heavier, it is their turn to take the incredible journey to their birthplace.

Kokanee salmon are simple creatures requiring only a few basics: cold, sediment-free, well-oxygenated water with an abundance of zooplankton on which to feast and the quick wit to outsmart predators such as trout, herons, osprey and mergansers. Unfortunately, kokanee can easily be limited by a loss of any essential attributes. A productive run, such as one that we have seen in 2001, is monumental and should continue to be respected, celebrated and embraced by the community.

No Website of the Week: Instead, shut down your computer and visit the Valley Trail bridge at the bottom of Lorimer Road. You’ll see live-action, bright red kokanee on either side – in real-time and with no annoying interruptions from Microsoft.

Upcoming Events:

Saturday, Sept. 22nd — Alpine Nature Walk: Take a casual alpine walk with other local naturalists while learning about geology, glaciers and alpine animal and plant life. Free for members and children; $5 for adult non-members (lift ticket not included). Meet at the base of the Whistler Gondola at 9:45 a.m. with your ski pass, warm clothes, and lunch. Total time about 4 hours.

Saturday, Sept. 29th — Arbor Day Planting in the Emerald Forest: The RMOW is again hosting Arbor Day, this year with all planting focused on the new Emerald Forest Conservation Area. The Whistler Naturalists will be meeting at 9 a.m., rain or shine, at the base of Lorimer Road. Planting will take about 3 hours.

Mushroom Walk — postponed. Due to bad mushrooming weather (not enough rain!) our mushroom walk has been postponed, likely to early October. We’ll post the new date in this space.

For more information about upcoming events hosted by the Whistler Naturalists, contact Bob Brett (932-8900; email: snowline@direct.ca).

Sightings and Memberships: NatureSpeak is prepared by the Whistler Naturalists. To become a member or to report noteworthy sightings of mammals, birds, or other species, contact Lee Edwards (905-6448; e-mail: leighe11@hotmail.com).

Comments

Subscribe to this thread:

Add a comment

Readers also liked…

Latest in Environment

Sponsored

Demystifying the rules around renting out your Whistler home

From average price per night to acquiring the proper license, here’s what you need to know...more.

© 1994-2018 Pique Publishing Inc., Glacier Community Media

- Website powered by Foundation