01-31-2003, 03:46 AM
Today I received the following from a UDWR biologist:
"Sorry it has taken a while to respond. I hope I can answer some of your
questions about age and growth of cutthroat and lake trout.
Let me begin with lake trout. They are slow growing and difficult to
age here in the lower 48 states. They can live to 30 years and some
even longer. We do not age them either here at Bear Lake or from
Flaming Gorge since it is nearly impossible. I've spoke with the
biologist at FG and he told me that a student working on a M.S. degree
did a little bit of tagging in the 1980's and used that data for
producing growth estimates. His name was Dan Yule and, if your so
inclined you can look at his M.S. thesis at the USU library for more
exact data on FG lake trout growth rates. In productive environments,
lake trout may grow up to approximately 3 lbs/year. However, they also
will reach a maximum size then lose weight and length during the rest of
their lives. I've witnessed a 30 year lake trout from Bear Lake that
weighed 9.5 pounds. On the other hand I've seen 15 year old lakers that
weighed near 20 pounds.
Cutthroat trout in Bear Lake grow slow and live long. They may reach
an age of 12 years, but that would be an extreme. Most cutthroat will
mature at 4-6 years old and live to about 10 years old if they are not
caught by fishermen. Approximate length at age data is as follows for
Bear Lake:
age 1 - 8 inches
age 2 - 11.5 inches
age 3 - 14.5 inches
age 4 - 16.5 inches
age 5 - 18 inches
age 6 - 19 inches
age 7 - 21 inches
age 8 - 23 inches
age 9 - 25 inches
These are only approximate. I've seen some 7 year old cutthroat over
25 inches. The same strain of fish in Strawberry Reservoir (much higher
productivity) grow much faster. On average a 14 inch fish from Bear
Lake would weigh about 1 pound. A 19 incher would weigh about 2-3
pounds. Fish over 20 inches typically will weigh about 1 to 1.5 pounds
more per inch over 20 inches... Cutthroat trout run up the Swan Creek to spawn each spring and are captured in our egg taking trap. We handle each of these fish and they are tagged and released. Lake trout are lake spawners and we don't encounter them except in gillnets as part of our monitoring efforts on Bear Lake. The lakers that are only caught in the nets by their teeth, fins or have no critical damage to their gills are tagged and released. This amounts to only about 15 lake trout per year that are tagged and released."
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"Sorry it has taken a while to respond. I hope I can answer some of your
questions about age and growth of cutthroat and lake trout.
Let me begin with lake trout. They are slow growing and difficult to
age here in the lower 48 states. They can live to 30 years and some
even longer. We do not age them either here at Bear Lake or from
Flaming Gorge since it is nearly impossible. I've spoke with the
biologist at FG and he told me that a student working on a M.S. degree
did a little bit of tagging in the 1980's and used that data for
producing growth estimates. His name was Dan Yule and, if your so
inclined you can look at his M.S. thesis at the USU library for more
exact data on FG lake trout growth rates. In productive environments,
lake trout may grow up to approximately 3 lbs/year. However, they also
will reach a maximum size then lose weight and length during the rest of
their lives. I've witnessed a 30 year lake trout from Bear Lake that
weighed 9.5 pounds. On the other hand I've seen 15 year old lakers that
weighed near 20 pounds.
Cutthroat trout in Bear Lake grow slow and live long. They may reach
an age of 12 years, but that would be an extreme. Most cutthroat will
mature at 4-6 years old and live to about 10 years old if they are not
caught by fishermen. Approximate length at age data is as follows for
Bear Lake:
age 1 - 8 inches
age 2 - 11.5 inches
age 3 - 14.5 inches
age 4 - 16.5 inches
age 5 - 18 inches
age 6 - 19 inches
age 7 - 21 inches
age 8 - 23 inches
age 9 - 25 inches
These are only approximate. I've seen some 7 year old cutthroat over
25 inches. The same strain of fish in Strawberry Reservoir (much higher
productivity) grow much faster. On average a 14 inch fish from Bear
Lake would weigh about 1 pound. A 19 incher would weigh about 2-3
pounds. Fish over 20 inches typically will weigh about 1 to 1.5 pounds
more per inch over 20 inches... Cutthroat trout run up the Swan Creek to spawn each spring and are captured in our egg taking trap. We handle each of these fish and they are tagged and released. Lake trout are lake spawners and we don't encounter them except in gillnets as part of our monitoring efforts on Bear Lake. The lakers that are only caught in the nets by their teeth, fins or have no critical damage to their gills are tagged and released. This amounts to only about 15 lake trout per year that are tagged and released."
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