Field Notes

Aaron Voirol’s journey from local baseball player to DNR hatchery biologist reveals the fascinating world of fish management happening beneath the surface of Indiana’s lakes. As a Grace College environmental science graduate who worked at the Lilly Center for Lakes and Streams, Aaron brought unique “fish IQ” and “boating IQ” skills that set him apart even before launching his professional career.

Now stationed at Fawn River State Fish Hatchery, Aaron meticulously manages fish culture and feeding programs aimed at raising species like walleye and muskie for stocking throughout Indiana’s public lakes. His detailed explanation of lake stratification illuminates why cold-water species like Cisco face survival challenges – as nutrients feed more weeds and algae, decomposition depletes oxygen in deeper waters where these fish need to live, effectively squeezing them out of their habitat.

The complexity of Indiana’s seven-hatchery system comes alive as Aaron describes how these facilities coordinate efforts based on specialized capabilities. Perhaps most fascinating is the muskie spawning program at Webster Lake, where biologists collect adult fish and artificially spawn them, harvesting up to 600,000 eggs from just 15-20 females. Though only about 15,000 stockable fish ultimately result from this process, it far exceeds what would survive through natural reproduction.

Aaron’s explanation of trophic cascades reveals why predator fish like walleye and muskie are crucial for lake health – they control populations of smaller fish, which affects zooplankton levels and ultimately algae abundance. Through carefully calculated stocking rates (approximately 10 fingerlings per acre), hatchery biologists help maintain clearer, healthier lakes with balanced ecosystems. His recent election to chair the Walleye Technical Committee for the North Central District of the American Fisheries Society speaks to his growing expertise and contribution to fisheries management across the Midwest.