Center-Initiated Rapid Response Research:  Helping Fisheries Managers Provide Healthier Trout

Through judicious and conservative spending, the Water Center has begun supporting Center-initiated research. Funding is available so that faculty can initiate research quickly on acute problems and high-priority issues identified by partners, but for which no funding mechanism exists or where it would cause harm to wait up to a year to write traditional proposals for the grant-funding cycle that peaks during the winter. Our first rapid response effort focuses on water quality in State fish hatcheries.

The TWRA relies on hatchery trout for stocking into our nationally recognized tailwater fisheries, and maintaining large numbers of healthy trout is vital. But, TWRA personnel are faced with nitrogen supersaturation in the springs that supply water to many hatcheries. The reasons underlying supersaturation are not well understood, but they cause trout to experience what human divers would call “the bends.” This makes them less healthy, and can even kill fish. Hatchery staff flood incoming water with oxygen to strip off excess nitrogen, but enough nitrogen can remain to create issues, and the truckloads of liquid oxygen required to support the process are expensive.

A team of nine undergraduate chemical engineering students explored ways of reducing nitrogen by testing different ways to set up the stripping columns. They partnered with Red Silo Brewery to created chilled supersaturated water in the laboratory and were collecting data when forced to leave campus due to statewide pandemic lock-downs. However, they were able to help us understand system dynamics prior to going home.

As soon as it was safe to do so, we resumed the project using a graduate student who has transitioned the work to field experiments at Buffalo Springs hatchery. Using the laboratory data, he created a novel diffuser column, and field trials are underway. While we need to accomplish extensive field testing under different conditions, initial results suggest that we can provide more oxygen and reduce nitrogen saturation at far higher efficiencies than the present systems. It requires far less pure oxygen to produce the water quality needed by trout, and should substantially reduce the amount of liquid oxygen that the hatchery needs to purchase.  And, the student’s invention can be constructed primarily from about 100 dollars of materials that one can find at the hardware store.

The Water Center is looking forward to new opportunities to work with the State on hatchery water quality.  We have interdisciplinary expertise, and the students love working on real-world issues.