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In
Yellowstone, bald eagles, ospreys, pelicans, otters, grizzly
bears, and other wildlife take precedence over humans in
utilizing fish as food. None of the fish in Yellowstone are
stocked, and populations depend on sufficient number of
spawning adults to maintain natural reproduction and genetic
diversity. In Yellowstone National Park, we place less
emphasis upon providing fishing for human consumption and
put more emphasis upon the quality for recreational fishing.
Anglers, in return, have the opportunity to fish for wild
trout in a natural setting.
As of
the summer of 2001, all native sport fish species in
Yellowstone National Park became subject to
catch-and-release-only fishing rules. The native species
affected by this change are the cutthroat trout and its
several subspecies, Montana grayling, and mountain
whitefish. Most of the park’s native fishes have been
included under catch-and-release-only fishing rules since
the early 1970’s. The changes effective in 2001 primarily
affect populations in Yellowstone Lake, its tributaries, and
the upper Lamar River.
Evidence of the geological forces that
have shaped Yellowstone are found in abundance in this
district. The hills surrounding Old Faithful and the Upper
Geyser Basin are reminders of Quaternary rhyolitic lava
flows. These flows, occurring long after the catastrophic
eruption of 600,000 years ago, flowed across the landscape
like stiff mounds of bread dough due to their high silica
content.
Mountain building is evident as you drive
south of Old Faithful, toward Craig Pass. Here the Rocky
Mountains reach a height of 8,262 feet, dividing the country
into two distinct watersheds.
Mammoth Hot Springs
are a surficial expression of the deep volcanic forces at
work in Yellowstone. Although these springs lie outside the
caldera boundary, their energy is attributed to the same
magma tic system that fuels other Yellowstone thermal areas.
Hot water flows from Norris to Mammoth along a fault line
roughly associated with the Norris to Mammoth road. Shallow
circulation along this corridor allows Norris' super-heated
water to cool somewhat before surfacing at Mammoth,
generally at about 170° F.
The Mammoth area exhibits much evidence of glacial
activity from the Pinedale Glaciations. The summit of
Terrace Mountain is covered with glacial till, thereby
dating the travertine formation there to earlier than the
end of the Pinedale Glaciations. Several thermal kames,
including Capitol Hill and Dude Hill, are major features of
the Mammoth Village area. Ice-marginal stream beds are in
evidence in the small, narrow valleys where Floating Island
Lake and Phantom Lake are found. In Gardner Canyon, one can
see the old, sorted gravel bed of the Gardner River covered
by unsorted glacial till.
Bison are the
largest mammals in Yellowstone National Park. They are
strictly vegetarian, a grazer of grasslands and sedges in
the meadows, the foothills, and even the high-elevation,
forested plateaus of Yellowstone. Bison males, called bulls,
can weigh upwards of 1,800 pounds. Females (cows) average
about 1,000 pounds.
More than 30,000 elk from 7-8 different herds summer in
Yellowstone and approximately 15,000 to 22,000 winter in the
park.
With a surface area of 136 square miles, Yellowstone Lake
is the largest lake at high elevation (i.e., more than 7,000
ft.) in North America. It is a natural lake, situated at
7,733 ft. above sea level. It is roughly 20 miles long and
14 miles wide with 110 miles of shoreline. It is frozen
nearly half the year. It freezes in late December or early
January and thaws in late May or early June. |
