by Vanessa Villarreal, USACE Chicago District
For eight months out of the year, fish biologists at the U.S. Army Corps of Engineers, Chicago District take to the waters of Illinois to monitor fish populations at restoration sites throughout its area of responsibility. The team also tracks and monitors Asian carp below the electric dispersal barrier system in Romeoville, Illinois, within the Lockport, Brandon Road, and Dresden Island navigation pools.
“Sampling fish is always an adventure,” Matt Shanks, fish biologist in the Planning Branch, said. “You never know what species you might find in your net.”
To determine the condition and success of a project, the team uses a process that involves a series of models. Some of these condition and success parameters are linked to fish communities which can be sampled using a number of methods that include electrofishing.
Electrofishing is conducted via the creation of an electric field that is detectible in the water up to 10 feet in all directions. The field is created using a generator that provides power to a control box where it is then transferred to two boom arms that distributes the electricity in the water. The district owns one electrofishing boat, with a new boat slated for delivery this spring.
“In general, we try to adjust our settings to put approximately 15 amps into the water,” Nick Barkowski, fish biologist, said. “The control box allows us to adjust the electrical settings to optimize our effectiveness. Netters at the front of the boat use nets to pick up fish as they are temporarily stunned – which doesn’t hurt the fish at all. Each fish that we place in a live well on the boat are then identified and returned back to the water.”
Within the past two years, monitoring occurred at five restoration projects: River Riparian along the North Branch Chicago River, Ft. Sheridan, Morton Arboretum, Northerly Island in Illinois, and Jeorse Park Beach in Indiana.
Sampling fish communities provides a quick and effective technique to assess the health and function of an aquatic system. The frequency of sampling for a restoration project varies, but typically the team tries to get out one to two times a year for each project. Monitoring plans are developed during the feasibility study for each project, tailored specifically to the project goals and objectives.
According to John Belcik, fish biologist and planner, when determining the success of a restoration project, if we know a project will or can have significant impacts on aquatic resources, a baseline assessment is done first to determine what the current health of the system is. Then a post-construction survey takes place after construction is completed to determine if or how the fish community has changed, and if it has improved from what it was before construction.
“The frequency of these surveys can vary anywhere from just once before and after construction to multiple times at various time intervals – like different seasons or years,” he said. “It just depends on the project.”
And he said one project that stands out is Northerly Island.
“Each time we monitor at Northerly Island, we seem to get a new species that we have not documented in the project area,” he said. “In addition, we specified the importance of the project to promote the state-threatened Banded Killifish, and each time we are there we have collected at least one specimen.”
According to Frank Veraldi, ecologist and regional technical specialist, another success story is the dam removals on the Des Plaines River that included Hofmann Dam.
“These, and several other species, have either become present or increased in abundance due to the Hofmann Dam and other dam removals on the Des Plaines River where connectivity is imperative for diverse and healthy fish populations,” he said. “Specifically, the Logperch, Carmine Shiner, and the state-endangered Blackchin Shiner.”
Barkowski said his main role last year was to assist and lead monitoring efforts for Asian carp in the Chicago-area waterway system. This included conducting electrofishing surveys and tagging various fish species to track their movements.
While standard monitoring efforts are key to understanding a project’s success, district fish biologists are also involved in cutting edge research that will benefit the Corps’ environmental missions in the future. Barkowski has been getting more involved in recent years with the use of acoustics to attract and deter Asian carp through a partnership with the Corps’ Engineer Research and Development Center in Vicksburg, and the U.S. Geological Survey. This type of research may lead to greater capture efficiency or new barrier technology for implementation in the fight against these invasive species.
Shanks said he looks forward to the 2020 sampling season.
“Next year will be an exciting time to be sampling fish near the barriers system,” he said. “Permanent Barrier I will be going online in the fall and will have significantly higher output capabilities. It will be interesting to see how these new parameters begin to change the efficacy of our project.”