Mike Hawkins – DNR Fisheries Bureau Biologist – has provided the following information as an update on the Asian Carp situation:


Our staff continue to aggressively sample our lakes and the Little Sioux River for Asian carp. In fact, our team, with help from the Aquatic Invasive Species staff from Boone, electro-fished two stretches of the Little Sioux River yesterday – one stretch near the Twin Forks area in Dickinson County and one stretch near the Little Sioux Wildlife Management Area in Clay County. If present, Asian carp would most likely be gathered in pools below rocky riffle areas. We sampled this type of habitat in both locations and did not see any Asian carp. As you may remember from my last update, silver carp are very sensitive to the electrofishing boat and will readily jump out of the water around the boat if present.

We were not as fortunate two weeks ago when we used the same electrofishing boat to sample below the Linn Grove Dam in northern Buena Vista County. We did see numerous silver carp jump out of the water.

We have continued electrofishing in the area lakes and have not been able to sample or observe an Asian carp. We will continue to monitor as conditions change.

The commercial angler has not seined again in the lakes since my last update. His final hauls of the season yielded no Asian carp.

All indications are that Asian carp numbers in our lakes are low. We also think that numbers in the Little Sioux River above the Linn Grove Dam are also low.

Electric Fish Barrier Status

We continue to stay on schedule for construction of the electric fish barrier on the outlet of the Iowa Great Lakes to begin this fall. The following paragraph was released by our Des Moines staff that are overseeing the process. Be assured, we are moving this complicated and involved project as quickly as allowed by State Law.

“The request for proposals (RFP) to design the barrier was posted May 4th. Two firms have contacted us with interest in the project. The deadline for submitting an RFP is June 1st. Webinars have be scheduled for June 5th for firms to explain their proposal, sell themselves and for our staff to ask questions. A staff recommendation to hire the highest ranking firm will be presented to the Natural Resources Commission (NRC) at their June 14th meeting. DNR staff will start the process to secure required permits early in the design stage. Final barrier design is due August 15. DNR will post a request for proposal to construct the barrier soon after that. Fisheries staff has been communicating with DNR Engineering staff who will be responsible for bid advertisement, bid letting and oversight during construction. They are aware of the urgency of the project. Our schedule calls for a December 1, 2012 completion date. Staff will do everything possible to keep the project on schedule however this is very tight schedule with the potential for possible delays.”

Temporary Barrier

After consulting with engineers, local contractors and biologists, we have come up with a design for a temporary barrier. This has been no easy task and we have no guarantees that the design will work effectively, but we want to make sure we to do everything possible to stop Asian carp from moving before the installation of the permanent barrier. The challenges of placing a barrier in a moving stream are quite complex. It must be able to stand up to incredible water pressures and cause as little plugging as possible while not being so complicated it takes months to fabricate and install. The spacing required to stop these fish is not known so we are using our best science to make a guess. The temporary barrier is predicted to require nearly continuous monitoring to prevent plugging and we have made a decision that as water levels rise, it may need to be removed when it becomes too dangerous to maintain. It is not a perfect solution but could prevent movement of fish during low to moderate flows. It will be removed when the electric barrier is in place. A local donor has graciously agreed to fund the temporary barrier so it can move forward as quickly as possible. Fabrication will begin almost immediately. My hope is that water levels remain low and we don’t have to find out if it works.

Final Thought

I have been questioned numerous times about why we didn’t do this project a few years ago. Believe me, the idea was out there and was advocated for, unfortunately it took a flood of Asian carp to get enough attention.

As I write this update, I can see the western sky turning dark and have read the forecast. My wife has noticed I’ve been doing a lot of pacing at home whenever we hear rain on the roof, tonight will be no different. So many people locally and within our department have been working long hours to do everything we can to prevent another surge of these fish from moving into the lakes. The thought of another event like last summer is disheartening. We must remain confident we have done all we can to this point and continue to move forward with our plans.