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In 1888 William G. Steel, considered the founder of Crater
Lake National Park, made the first recorded attempts to stock
Crater Lake. National Park Service researchers believe that before
that time, Crater Lake contained no fish. William Steels
motive for stocking the lake was probably to improve the lake's
recreational value.
Around the turn of the century, a regular stocking program
was begun. Stocking continued through the early part of the century
until creel censuses showed that the fish were naturally reproducing.
Six species were introduced to Crater Lake during this time.
The last recorded stockings were silver salmon in 1937 and rainbow
trout in 1941.
Later investigations revealed that the naturally reproducing
silver salmon were actually kokanee salmon. Since kokanee were
not intentionally introduced, researchers believe that one of
the plantings of silver salmon fingerlings was actually kokanee.
Of the six species introduced, two remain:
Kokanee Salmon (Oncorhynchus nerka)
are a dwarf, landlocked form of sockeye salmon. Kokanee are the
most abundant species in the lake, estimated to have a population
well into the hundreds of thousands. An average kokanee is about
8 inches long, but some grow to as long as 18 inches.
Rainbow Trout (Oncorhynchus mykiss)
are less abundant than the kokanee, but are typically larger.
The largest documented rainbow trout from Crater Lake was a 6
1/2 pound, 26 inch long specimen caught by the park research
team. Most rainbows average 10 to 14 inches.
Rainbow trout and kokanee salmon populations are stable in
the lake. Researchers believe that this stability is due to each
fish species eating different foods. Kokanee feed on zooplankton
and rainbows feed on aquatic insects.
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