Lake Francis Case Walleye/Sauger/Hybrids

Lake Francis Case Walleye Regulations (For specifics, see pages 16-17 in the 2013 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 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 they catch.

Overall walleye abundance in the 2012 survey decreased to a level similar to 2009. Abundance of harvestable size walleye (those >15 inches), in the 2013 LFC population is lower than what was present in the reservoir in 2012. However, the average size of harvestable size walleye remains above average. Good numbers of walleye less than 15 inches are present in the population and should be common in angler catches. These young fish are important, as they replace those fish harvested by anglers or lost to natural causes.

High walleye production during 2005 and 2006 currently provides good numbers of larger fish in the population. Moderate production in 2009 and excellent production in 2010 should support the bulk of the harvest in 2013. Excellent walleye production occurred in 2011 and moderate production in 2012. To help ensure good fishing in future years anglers should be conservative in the number of walleye they choose to harvest in 2013, not only on a given day, but throughout the entire fishing season.

Water, what a difference a year makes!
Widespread flooding engulfed the Missouri River during 2011. Record setting water yield in the Missouri River basin caused mass destruction up and down the river basin. While we hope there will never be a repeat of this event, there were some positive effects of the flooding. Run-off into the Missouri River system is key for fish production. Localized run-off provides the reservoir with nutrients needed to produce plankton; small creatures that our bait-fish and newly hatched game fish eat. During periods of high run-off, the reservoir is capable of supporting high numbers of fish. Drought conditions seriously decrease the reservoir's ability to produce and maintain fish populations. During low run-off periods, the reservoir simply does not have the nutrients needed to support large numbers of fish. As the graph below shows, run-off in the Missouri River basin has been at or above average (25.2 million acre-feet (MAF), depicted by the red line) from 2008-2011 following eight years of below normal conditions, which has increased reservoir productivity. Run-off into the Missouri River basin above Sioux City during 2012 was 19.7 MAF, a drastic decline from the 60 MAF measured during 2011, the highest on record.

Lake Francis Case Fishing Use 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 time 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 such as emerald and spottail shiners, young yellow perch, young white bass and a host of different minnows, shiners and darters provide a valuable source of prey.

Biologists often use catch rates to help determine the quality of a fishery. A catch rate is the number of fish caught per hour of fishing. For example, a walleye catch rate of 0.5 walleye/hour means 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.  Newly hatched gizzard shad 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 food being plentiful. The chart below helps illustrate how angler success on Lake Francis Case is influenced by prey-fish abundance.

Biologists index fish condition or plumpness using relative weight (Wr). LFC walleye relative weights are typically in the high 70s or low 80s. As the chart below illustrates, LFC walleye relative weights for all size ranges of walleye have been above 80 for the past few years.