02-22-2013, 10:04 PM
HI,
Partial treatments have been tried in a number of waters throughout the country for the last 80 years or so that rotenone has been a management tool. They usually depend on the target species being aggregated into a relatively small area that can be blocked off with a seine to prevent escapement from the chemical once they sense it in the water. For this reason they are often known as "cove rotenone" treatments.
These conditions do not exist in Scofield so a partial treatment would likely not achieve its intended goals. The fish would simply leave the area and move to a location where the chemical concentration would be low enough to allow them to survive.
One other drawback to a cove rotenone treatment is that they normally have to be repeated every few years to maintain the level of control desired. This is especially true when dealing with a highly reproductive fish like Utah chubs.
According to some work that we did at Joe's Valley when we were attempting to net out the cubs from 2005-208, a single female chub produces 11,000 eggs (compared with 1000-2000 for a female trout). In the three years of netting pre-spawn chubs, we removed about 40,000 pounds of chubs and an estimated 940,000,000 (yes,, nearly a billion) eggs from the system. At the end of a lot of hard work, it made absolutely no difference. The remaining chubs just reproduce too fast for partial methods to be effective.
I would like to say that I appreciate all of the different points of view that have been expressed in this thread thus far. Approximately 12 months from now we will have all of the data assembled, can hopefully do some modeling of different scenarios, and will be making a recommendation on what management direction we would like to take at Scofield. I hope to hear from all of you again at that time.
The DWR's mission statement is that we are the caretakers and guardians of the public's resource. We will eventually do what is legal, fiscally responsible, and in the interest of the majority of the angling public.
Paul Birdsey
Coldwater Sportfish Coordinator
Utah Division of Wildlife Resources
[signature]
Partial treatments have been tried in a number of waters throughout the country for the last 80 years or so that rotenone has been a management tool. They usually depend on the target species being aggregated into a relatively small area that can be blocked off with a seine to prevent escapement from the chemical once they sense it in the water. For this reason they are often known as "cove rotenone" treatments.
These conditions do not exist in Scofield so a partial treatment would likely not achieve its intended goals. The fish would simply leave the area and move to a location where the chemical concentration would be low enough to allow them to survive.
One other drawback to a cove rotenone treatment is that they normally have to be repeated every few years to maintain the level of control desired. This is especially true when dealing with a highly reproductive fish like Utah chubs.
According to some work that we did at Joe's Valley when we were attempting to net out the cubs from 2005-208, a single female chub produces 11,000 eggs (compared with 1000-2000 for a female trout). In the three years of netting pre-spawn chubs, we removed about 40,000 pounds of chubs and an estimated 940,000,000 (yes,, nearly a billion) eggs from the system. At the end of a lot of hard work, it made absolutely no difference. The remaining chubs just reproduce too fast for partial methods to be effective.
I would like to say that I appreciate all of the different points of view that have been expressed in this thread thus far. Approximately 12 months from now we will have all of the data assembled, can hopefully do some modeling of different scenarios, and will be making a recommendation on what management direction we would like to take at Scofield. I hope to hear from all of you again at that time.
The DWR's mission statement is that we are the caretakers and guardians of the public's resource. We will eventually do what is legal, fiscally responsible, and in the interest of the majority of the angling public.
Paul Birdsey
Coldwater Sportfish Coordinator
Utah Division of Wildlife Resources
[signature]