Dear USACE Project Managers:
I am writing to comment on the ongoing debate over the placement of Asian carp barriers in the Tennessee River System. My interest, dating back to my service as District Biologist for the Tennessee Game and Fish Commission in the early 1970’s, is in preserving and protecting the rich biodiversity of the East Tennessee River headwaters. If the carp are allowed access to these biologically rich river reaches, the biological impact will be devastating, to say nothing of the economic impact.
Evidence of such biological devastation has been clearly demonstrated in the lower Tennessee River reaches and in large portions of other major rivers such as the Ohio, Mississippi, and Missouri River systems. The goal of any barrier placement must be on stopping the spread into uninfested reaches. This is just common sense and has been endorsed by most legitimate organizations involved in invasive species management.
As I understand it, the current plan is to place the initial barriers within the already heavily infested lower Tennessee River reaches (Kentucky and Barkley lakes, etc.). This makes no sense to me, and such barrier placement decisions appear to be based more on politics than on science. I doubt if such placement will have any measurable effect on population numbers either above or below such barriers. The carp are very prolific spawners and reportedly are already present in large enough numbers both above and below such barriers sites that their numbers will continue to grow regardless of any barrier placement. The only real solution to population control in such highly infested areas is removal of mature spawners through harvest or by other means. Once the numbers have been reduced, then perhaps barrier placement may be feasible.
On the other hand, we have an excellent opportunity to stop the spread into the uninfested Upper Tennessee River reaches if we act quickly and place barriers upstream of the invasion. Based on reported Asian carp captures that location appears to be upstream of the Watts Bar and Chickamauga locks. In his published models (Zielinski & Sorensen 2021), Dr. Peter Sorensen at the University of Minnesota has shown that pairing barriers at two dams (locks) will block 99+% of all carp. Therefore, the first barrier must be placed at the Watts Barr Lock and, if funding allows, a second should be placed at the Chickamauga Lock.
Obviously funding is limited, so barrier placement decisions must be based on science, not on politics. Unless we have stopped the upstream spread, any recommendation to place barriers in the middle of an infestation unfortunately appears to me to be based solely on politics and should be blocked.
We have one chance to get this right or to forever wish we had! Once the carp bypass an upstream barrier, the party is over so let’s close the door as fast as we can by placing a barrier at the Watts Bar Lock!
Thank you for the opportunity to comment.
Sincerely,
Jerry L. Rasmussen
MICRA/MRBP Coordinator 1990-2008
USFWS Retired