Lake Francis Case Walleye/Sauger or Hybrids

Lake Francis Case Walleye Regulations (For specifics, see pages 21-23 in the 2008 Fishing Handbook)

• 4 fish daily/8 in possession
• Minimum walleye length limit is 15 inches and is in effect from Jan. 1-June 30 and Sept. 1-Dec. 31, annually (all months of the year except July and August).
• Anglers are allowed only one walleye/sauger 20 inches or longer per day in their daily limit, year round.
• High-grading or culling of walleye is prohibited.
• The area between the railroad bridge and the I-90 causeway in Brule and Lyman counties is closed to fishing during January, February, March, April and December, except that shore-fishing is allowed from the Brule County side year-round.
• When anglers are fishing through the ice in the area from the northern Gregory-Charles Mix county line downstream to Ft. Randall Dam, size restrictions do not apply and anglers are required to keep the first four walleye/sauger they catch.

The abundance of harvestable sized walleye (those >15 inches), in the 2008 Lake Francis Case walleye population, is lower than what was present in the reservoir in 2007.  Poor walleye production from 2001 to 2004 has resulted in fewer fish over 15 inches in the current population.  Good natural walleye production occurred in 2005 and 2006.  As a result, anglers should expect good catches of sub-legal length walleye during 2008.  With average growth, fish produced in 2005 will begin to surpass the 15 inch minimum length in 2008.  To ensure that good fishing continues in the near future, Lake Francis Case anglers need to take a conservative approach to how many fish they choose to harvest, not only on any given day, but throughout the fishing season.  Good fishing in future years will require that anglers be selective in the number of walleye they choose to harvest in 2008.

Lake Francis Case Fishing Pressure and Walleye Harvest

For anglers unfamiliar with Lake Francis Case walleye, fish can be found year-round throughout the reservoir.  However, the typical yearly pattern has a majority of the spawning size walleye moving into the upper 1/3 of the reservoir in late fall/early spring.  After spawning in mid/late April, walleye begin to disperse throughout the reservoir.  As water temperatures rise, walleye fishing can be good throughout the entire reservoir.  Lake Francis Case typically sees most of its fishing use during the May-July time period.  Consequently, this is also the time period when a majority of the walleye harvest occurs.  When you have more people on the lake fishing, more fish are harvested, as shown in the chart below.

What do Lake Francis Case walleye eat?

The primary forage fish species in Lake Francis Case is gizzard shad.  Due to gizzard shad being intolerant of cold water temperatures for extended periods, a majority of the young gizzard shad in Lake Francis Case die each winter.  Fortunately, there are enough warm water refuges, associated with numerous artesian wells located throughout the reservoir, to over-winter a sufficient number of adult shad to produce a year class of shad each spring.  Other forage fish species found in Lake Francis Case include emerald and spottail shiners, yellow perch, white bass and a host of different minnows, shiners and darters.

Biologists often use catch rates to help determine the quality of a fishery.  Catch rates are the number of walleye caught per hour of fishing.  For example, if the catch rate is 0.5 walleye/hour, it takes an average of 2 hours for an angler to catch a walleye.  Catch rates of walleye and other sport fish that depend on young gizzard shad for food are typically highest in May and June as food resources are limited due to the die-off of young gizzard shad during winter.  Gizzard shad begin spawning in late May or early June, and newly hatched gizzard shad typically reach a size desirable to walleye by about mid July, at which time catch rates of walleye typically decline on Lake Francis Case due to there being plenty of food for walleye to eat.  The chart below helps illustrate how angler success on Lake Francis Case is influenced by prey-fish abundance.