02-01-2008, 09:17 PM
Br0wn -- you know nothing of Minersville, obviously.
Fish stocked in Minersville must be done in the fall and at a particular size. Why? Because migratory cormorants move to Minersville in the spring. If trout are not over 12" by spring, they get eaten. All of them. If 8" trout are stocked in the spring, they get eaten. If 8" trout are stocked in the fall, they grow large enough over the winter to escape predation by cormorants. There are numerous studies on Minersville reservoir to prove this. Current managment strategies on Minersville Reservoir prove this.
You are correct that there is not one single bottleneck limiting growth. There are numerous bottlenecks. However, you MUST identify and manage one bottleneck at a time.
Is it age?
Is it food?
Is it competition?
Can you fix it?
Let's look at age. Many trout only live to be 4-6 years in the wild. What is it that is killing them? Old age? Harvest? something else?
My point? If trout are dying at age 5, and it's not "old age" that's killing them, would it make sense to stock a strain of trout know for it's long life?
Answer: No. Long life isn't the limiting factor.
At Strawberry, the rainbows aren't surviving for more than a year or two. Both angler harvest and predation by other fish are to blame. Would it make sense to stock Kamloops (a longer living, larger growing fish) than the current?
Answer: No. They will be harvested and eaten at the same rate as the current strain.
the former Southern Region Aquatics Manager for the UDWR spent many years experimenting with different strains of rainbow trout in Southern Utah. Attempts at growing larger fish based on strain were always failures. The reason? Strain wasn't the limiting factor in growth.
[signature]
Fish stocked in Minersville must be done in the fall and at a particular size. Why? Because migratory cormorants move to Minersville in the spring. If trout are not over 12" by spring, they get eaten. All of them. If 8" trout are stocked in the spring, they get eaten. If 8" trout are stocked in the fall, they grow large enough over the winter to escape predation by cormorants. There are numerous studies on Minersville reservoir to prove this. Current managment strategies on Minersville Reservoir prove this.
You are correct that there is not one single bottleneck limiting growth. There are numerous bottlenecks. However, you MUST identify and manage one bottleneck at a time.
Is it age?
Is it food?
Is it competition?
Can you fix it?
Let's look at age. Many trout only live to be 4-6 years in the wild. What is it that is killing them? Old age? Harvest? something else?
My point? If trout are dying at age 5, and it's not "old age" that's killing them, would it make sense to stock a strain of trout know for it's long life?
Answer: No. Long life isn't the limiting factor.
At Strawberry, the rainbows aren't surviving for more than a year or two. Both angler harvest and predation by other fish are to blame. Would it make sense to stock Kamloops (a longer living, larger growing fish) than the current?
Answer: No. They will be harvested and eaten at the same rate as the current strain.
the former Southern Region Aquatics Manager for the UDWR spent many years experimenting with different strains of rainbow trout in Southern Utah. Attempts at growing larger fish based on strain were always failures. The reason? Strain wasn't the limiting factor in growth.
[signature]