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Angling Publications - Index

Angling Publications - april2008 - Index

42
Tagging on Portage Creek
Steelhead—migratory rainbow trout, or more accurately, Oncorhynchus
mykiss—were originally introduced from the coastal
tributaries of the Pacific Northwest in the late 1880s. By the early
1920s they were firmly established in most suitable tributaries of Lake
Superior. Today, steelhead are an important component of the fish
community of Lake Superior and support a high-quality recreational
fishery. In the Canadian waters of Lake Superior, steelhead rely on
natural reproduction to maintain their numbers, and have developed
stream-specific life history characteristics that are genetically unique.
No artificial stocking is conducted, so the integrity of the natural
adaptations can be maintained. It seems that in merely one century,
the Superior strain of steelhead has adapted to the harsh climate and
nutrient deprived, granite-based stream conditions. The introduction
of hatchery steelhead would only weaken the fitness of the present
steelhead population; something that had been attempted on the
American shore of Lake Superior with detrimental effect.
Interestingly enough, the Canadian north shore of Lake Superior
is home to one of the most northerly, self-sustaining populations
of steelhead in the Great Lakes, and possibly has one of the coldest
climates on the continent where natural rainbow populations thrive.
(Mean temperature along the shore is colder than coastal Alaska.)
Life history strategies of Lake Superior steelhead are similar to wild
steelhead stocks in northeastern Russia (Kamchatka), an extreme
northerly indigenous population.
Portage Creek, one of the most exploited streams on the Canadian
side of Lake Superior, is a small tributary on Sibley Peninsula just east
of the city of Thunder Bay. The population size of adult steelhead
was between 400 and 600 individuals in 1993. In 1994 the stream
was closed to the public and access was restricted to scientific study.