Difference between revisions of "Trout Management Flows"
Cellsworth (Talk | contribs) (Created page with "---- __NOTOC__ __NOEDITSECTION__ <!-- ------------------------------Banner across top of page------------------------------> {| style="width:100%; background:#fcfcfc; margi...") |
Cellsworth (Talk | contribs) |
||
| Line 17: | Line 17: | ||
</table> | </table> | ||
| + | |||
| + | [[File:Lf10-trout-leesferry.jpg]] | ||
<!-- | <!-- | ||
| Line 23: | Line 25: | ||
|style="width:60%; font-size:120%;"| | |style="width:60%; font-size:120%;"| | ||
| − | The purpose of implementing | + | The purpose of implementing '''Trout Management Flows''' is to evaluate methods for using |
releases from Glen Canyon Dam to reduce the production of large numbers of age-0 rainbow | releases from Glen Canyon Dam to reduce the production of large numbers of age-0 rainbow | ||
trout in order to improve the quality of the Lees Ferry trout fishery and conserve the endangered | trout in order to improve the quality of the Lees Ferry trout fishery and conserve the endangered | ||
| − | humpback chub and other native fishes in Grand Canyon. | + | humpback chub and other native fishes in Grand Canyon. |
We identified three objectives that need to be addressed to support management decision | We identified three objectives that need to be addressed to support management decision | ||
| Line 32: | Line 34: | ||
*Sustain a healthy Lees Ferry trout population with a balanced age and size structure; | *Sustain a healthy Lees Ferry trout population with a balanced age and size structure; | ||
*Reduce annual production rates of rainbow trout in the Lees Ferry reach; | *Reduce annual production rates of rainbow trout in the Lees Ferry reach; | ||
| − | *Reduce emigration rates of rainbow trout from Lees Ferry to downstream reaches occupied by humpback chub. | + | *Reduce emigration rates of rainbow trout from Lees Ferry to downstream reaches occupied by humpback chub. [https://www.usbr.gov/uc/rm/amp/twg/mtgs/12feb02/Attach_08.pdf] |
|}<!-- | |}<!-- | ||
| Line 65: | Line 67: | ||
|style="color:#000;"| | |style="color:#000;"| | ||
| − | Trout Management Flows | + | [https://drive.google.com/file/d/0BwY-Z2c3NTUGUmxPbko2dm9URms/view '''Lees Ferry Anglers Trout Fishery Recommendations'''] |
| − | + | ||
| − | + | Recommendation #5. | |
| − | + | ||
| − | + | Under certain conditions, rainbow trout at Lees Ferry have reproduced prolifically. Historically, when there is an over-abundance of young-of-year rainbow trout, the quality and condition of rainbow trout decline. This is likely due to the low quality and low abundance of food sources in Lees Ferry. Trout Management Flows (TMFs) are flow treatments that are hypothesized to reduce the abundance of young-of-year trout by stranding trout shortly after they emerge from their redds (Korman, Ecometric Research, Inc., personal communications, 2015). | |
| + | |||
| + | We believe the best long term and ecologically appropriate solution to controlling trout densities is to increase invertebrate diversity and manage Grand Canyon Dam flows to avoid excessive trout spawning and recruitment (see recommendations related to the aquatic food base and equalization flows). We are concerned about the collateral damage that TMFs could have on other resources especially the aquatic food base and native fish. TMFs may be especially useful when spring HFE's are implemented or in years when high equalization flows are required. | ||
| + | |||
| + | TMF's should only be implemented in a carefully designed experimental framework that includes quantified criteria for success (for managing trout recruitment and improving the humpback chub population) and the impacts to other resources, especially the aquatic food base, are fully assessed. TMF's should only be used when the rainbow trout population is stable and includes a healthy abundance of all size classes of rainbow trout. Mitigation measures such as emergency stocking of trout need to be in place prior to the implementation of TMFs in case of catastrophic loss to the fishery (see recommendations on Trout Stocking). In conclusion, the experimental evaluation of TMFs needs to recognize the trout fishery as a highly valued asset. The AZGFD should have a seat at the table along with Federal agencies on any discussion and decisions related to implementation of TMFs. | ||
|- | |- | ||
| Line 88: | Line 94: | ||
[[File:TMFs2012.jpg]] | [[File:TMFs2012.jpg]] | ||
| + | |||
| + | Trout Management Flows may be more effective if targeted towards juvenile trout and not eggs or hatchlings. <br> | ||
| + | Juvenile trout are susceptible to fluctuating flows (adults are less so). <br> | ||
| + | Reducing the number or density of juvenile trout at Lees Ferry may: <br> | ||
| + | *reduce downstream migration (emigration) and conflicts with humpback chub | ||
| + | *reduce competition with adult trout and maintain/improve the Lees Ferry trout fishery (size, condition) | ||
Revision as of 11:11, 27 July 2016
|
|
The purpose of implementing Trout Management Flows is to evaluate methods for using releases from Glen Canyon Dam to reduce the production of large numbers of age-0 rainbow trout in order to improve the quality of the Lees Ferry trout fishery and conserve the endangered humpback chub and other native fishes in Grand Canyon. We identified three objectives that need to be addressed to support management decision making:
|
| -- |
-- |
|---|
|
