For decades the scientific name of the walleye was Stizostedion vitreum, but in recent years the name has been changed to Sander vitreus. The walleye was originally found throughout most of Canada and the northern half of the U.S. Naturally occurring populations in the U.S. were found from Georgia northward to New Hampshire and westward to North Dakota. The species has been widely introduced outside of its natural range and can now be found in 34 states - virtually anywhere in the U.S. where climate conditions and water temperatures are acceptable.
Historically, the walleye has been a prized fish both for eating and recreational fishing. Numerous surveys and professional publications consistently confirm the species is among the most preferred in North America and even Northern Europe. A member of the perch family, the walleye is closely related to sauger and yellow perch, and to other perch species in Europe and Asia. The characteristic reflective quality of this fish’s eyes is an adaptation for feeding in low-light conditions and, apart from their first weeks of life, walleye actually avoid bright light whenever possible.
During the past century a large commercial fishery existed for walleye in the Great Lakes, especially Lake Erie. Catches declined significantly over the past six decades, but the market is still supplied almost completely by wild-caught product. Aquaculture of walleye has focused on spawning, larval rearing and fingerling production for stocking in natural habitats and private impoundments.
Under natural conditions, walleye spawn in the spring when water temperatures warm to 42o to 50o F. This is typically February to June, depending on the location. Methods for off-season indoor spawning utilizing temperature and photoperiod control have also been optimized in recent years. Larvae are typically stocked into fertilized hatchery ponds to feed on zooplankton for the first weeks of life. Then, they are harvested at 1.5 to 2.5 in. and maintained in flow-through tanks with dim lighting for training on formulated feeds. Alternately, some hatchery operators have trained newly hatched fry directly onto artificial diets using turbid water in tanks. When larvae are incubated indoors and raised on artificial diets, 40% - 50% survival can often be attained by day 30.
Grow-out of feed trained walleye fingerlings still takes place primarily in ponds. However, walleye are a coolwater species, so pond culture is only feasible in certain regions. Temperatures above 20o F require close attention, and temperatures above 24o F can result in significant stress. In the past, fingerlings were stocked with minnows as forage, but feed training has allowed for the widespread use of manufactured diets.
Currently, almost all harvesting/marketing schedules revolve around selling advanced fingerlings and juveniles for stocking in natural habitats or private ponds. A 6 in. walleye can be worth $1.50 to $1.80, but raising that fish to food size under pond culture conditions will require another one to two growing seasons. As a result, pond grow-out to food size weights has universally been deemed impractical from an economic standpoint.
Alternative approaches to raising food size walleye include cage culture and use of recirculating aquaculture systems (RAS). Pure walleye still grow somewhat slowly in these systems, requiring 12 to 18 months to reach sizes large enough to market. However, hybrids between walleye and sauger are easily produced and have been shown to grow very well under RAS conditions. Market surveys indicate these hybrids can compete in the same food fish markets where pure walleye are traded.
While hybrids are not considered desirable for stocking into public or private waters as fingerlings, in RAS they can reach up to 2 lb. in their first year of life. RAS production of hybrid walleye has been demonstrated to be technically feasible, but production costs will ultimately determine whether this approach can be commercially feasible.
In the coming years, the most promising approaches for raising food size walleye or their hybrid will probably incorporate combinations of pond and tank culture. One example might include stocking newly hatched larvae in hatchery ponds at low- to medium densities (50,000 to 70,000 per acre), followed by feed training in tanks, followed by pond culture to stocker sized fish over the remainder of the summer, at which point grow-out in recirculating systems could be achieved over the following 8 to 12 months.
The 2018 USDA Census of Aquaculture reported a total of 42 operations producing cultured walleye. Of these, only four indicated sales of food size fish. Fingerlings or fry were sold by 20 farms and stocker sales were reported by 18 farms. Sales of fingerlings or fry totaled $2,188,000 while those of stockers totaled $469,000. Reported sales of food size walleye from aquaculture operations totaled only $258,000. Wisconsin reported 11 walleye operations, followed by Michigan and Minnesota with 7 farms each, and Iowa with 4. In total, 13 states reported walleye production.
Production costs, seasonality of production and year-round supplies of fingerlings have all been cited as major concerns for existing and potential walleye producers. Additionally, these fish require high protein diets, which can be costly. When planning a walleye farming facility, whether for fingerling, stocker or food fish production, it will be necessary to calculate the carrying capacity of the system in order to estimate capital costs, projected production, revenues and input requirements (especially fingerlings and feed). At this point, an evaluation can begin in order to determine if the operation will be large enough to generate profits and if so, a market analysis can be undertaken. Markets must be available to accommodate production when it is ready for harvest because maintaining fish beyond a harvestable size requires excessive feed, labor and energy costs as well as unproductive use of facilities and capital.
Although demand for walleye is high in many regions, current marketing barriers must be considered. The need to fillet fish for retail sales would force producers to sell to processors or to process the fish themselves with all the related permitting/licensing requirements and labor/facilities costs. Historically, markets in the upper Midwest have preferred two sizes of fillets: 4-6 oz. and 8-10 oz. To yield two 4-oz. skin-on fillets, a walleye must weigh roughly 1.25 lb. Although prices for skin-on fillets have ranged from $6 to $12 per lb. in recent years, premium quality large skinless fillets can sell at retail for more than $20 per lb.
Walleye or hybrid walleye producers could potentially utilize a number of marketing channels, including processors, seafood retailers and wholesalers, supermarkets and grocery wholesalers, restaurants, and food service distributors. All of these potential buyers will require regular, year-round supplies. In recent years an influx of smaller imported fillets from Eurasian pikeperch fisheries has shifted the traditional walleye market toward acceptance of smaller fillet sizes (potentially beneficial for aquaculture producers), while at the same time resulting in downward price competition which could limit profitability.
Even with an efficient, cost-effective production process, producers of walleye or walleye hybrids will still be forced to compete with wild-caught product from the commercial fishery. Markets are currently supplied through significant harvests in Canadian waters and also to a lesser extent in Michigan, Minnesota and Wisconsin. Aquaculture producers will need to distinguish their product as premium, locally grown, traceable, contaminant free and extremely fresh.
Preferred market sizes of 1 to 1.5 lb. can be produced in a combination production strategy, especially for hybrids, but supply and demand will determine the profitability of this approach. Economic models based on real world trials indicate break-even prices for 12 in. fish will probably range from $6.50 to $7.70 per lb. There are shortages of wild product at certain times of year, providing an opportunity for aquaculture producers to enter more established markets and then compete from that point onward based on demonstrated advantages of a farmed product.
Prepared by C. Greg Lutz, Louisiana State University Agricultural Center