More than a thousand walleye are in the six sets of circular water tanks at the UW-Stevens Point (UWSP) Aquaponics Innovation Center in Montello, Wis. And they swim around in near-total darkness, their environment protected by several sets of pitch-black curtains.
“Walleye are sunset and nighttime feeders,” explained Chris Hartleb, UWSP professor of aquaculture and the caretaker of this walleye colony. “This way, they can feed 24 hours a day. Plus, they’re very skittish fish—it takes almost nothing to startle them.”
There’s good reason to keep them calm. These fish are a key part of a two-year aquaculture research project funded by Wisconsin Sea Grant designed to compare the production of walleye, a native Wisconsin fish, and saugeye, a natural hybrid of walleye and sauger, in a recirculating aquaculture system and a closed aquaponics system.
As it reaches the midway point, the project, headed by Hartleb and Greg Fischer, Facility Operations Manager of UWSP’s Northern Aquaculture Demonstration Facility (NADF) near Bayfield, Wis., is looking more promising by the fish tank. Both Fischer and Hartleb spent the last year raising saugeye in tanks with low (30kg/m³), medium (60kg/m³ ) and high (90 kg/m³) densities at each facility.
“The saugeyes grew really well,” said Fischer. “We reached our target goal of growing a one-pound fish in less than a year at each of the three densities. We even had some fish up to two pounds.”
Source: Aquaculture’s Next Big Thing?