The
Origin of the Kokanee
Into
Glacial Lake Kutenai (created by glacial meltwater) swam the ever-willing
sockeye salmon, enroute from the Pacific ocean up the Columbia River,
pursuing its anadromous habit of ascending rivers to spawn in tributaries
of freshwater lakes. The sockeye quickly established spawning areas in the streams
flowing into Kootenay Lake, and probably along the shores of the
Lake itself.
By
9500BP, the glacial meltwaters had drained away to present proportions,
and Glacial Lake Kutenai was no longer.
Lower Bonnington Falls, between present day Nelson and Castlegar,
became the rocky valve that would control the entire Kootenay River
and Lake system.
Bonnington
Falls spelled the end of sockeye spawning in Kootenay Lake.
Every fish species has an upstream “burst speed,” a rate
of maximum swimming energy output it can maintain for no more than
a few seconds before rest is required.
The onrush of water at Bonnington Falls exceeded the burst speed
abilities of the sockeye, and thus it became a permanent biological
barrier. Aspiring sockeye
spawners were forced to turn back, and young Kootenay Lake sockeye,
perhaps sensing the irrevocable quickening of the waters just above
the falls, chose to stay put, giving up forever their anadromous
habit, and so becoming the
kokanee. The sockeye
and the kokanee although very similar and technically still able
to mate and produce offspring, have rendered themselves geographically
unable.
