They are doing a population estiment. All the fish they samples (750ish) were tagged with jaw tags. The fish are then released at the boat launch via hatchery truck so they disperse in the lake. They are then going to electro shock the lake with boats before the season starts to try and sample as many walleye as they can. Based on the total amount of walleye they sample in the lake and how many of those are of the 750 that got tagged they can figure out about how many walleye are in the lake. Sent from my iPhone using Lake Ontario United mobile app