In visiting with DNR Fisheries Biologists Jonathon Meerbeek, and Mike Hawkins, in addition to the annual stocking of fry on West and East Okoboji, biologists have been stocking larger walleye fingerlings raised at Iowa’s largest walleye rearing facility at Lake Rathbun in southern Iowa. This has been done, because of the longer growing season at Lake Rathbun.
Over the past few years, these 7-9 inch fingerlings seem to be helping increase walleye numbers in years when fry don’t survive well. However, these fish cost more to produce and the state has limited resources and space to raise this larger product. So, a study through Iowa State University aims to examine just how well these fish are doing and what kind of return they are having. The study may also find ways to improve the survival of these fish.
Hawkins says, “Walleye fingerlings will be monitored from the time they are put on the truck in southern Iowa, stocked into the lake and as they move into adulthood. Data collected will include their travel patterns after stocking, effects of predators and how many of these advanced fingerlings make it to a harvestable size and beyond.” Both biologists are looking forward to using the new ISU study to improve stocking methods.
When it comes to managing the fisheries here in the Iowa Great Lakes, Meerbeek and Hawkins look at it as both an art and a science. They collect large amounts of data related to walleye populations, but the real trick is being able to make predictions based on that data. They use complex simulation models to help provide insights into how increased stockings, changes in harvest regulations and changes in angler catch can impact the fishery.
Some people would argue managing fish is simple. However, these are not controlled environments. Instead, they are living, breathing environments with all kinds of variables. Just think of all of the species of fish interacting with each other and their surroundings, and each lake is different! Simple regulation changes can have impacts that ripple throughout the fishery. These impacts aren’t always easy to understand and may take years to assess. There is rarely a one size fits all solution in fisheries management.
Hawkins and Meerbeek assure anglers, “We will continue to aggressively monitor walleye populations in the Iowa Great Lakes, and we are not afraid to suggest changes in regulations or stocking if the data and models suggest a better solution exists.”