An update on the skinny walleye on Oahe and Sharpe…
Quote:
South Dakota GFP Missouri River Fisheries Updates
South Dakota Department of Game, Fish and Parks
Posted on June 13, 2012Lake Oahe
Walleye fishing should remain good on Lake Oahe through the spring of 2012 and into the summer. With the good fishing, questions remain on the status and health of the food supply in Lake Oahe. South Dakota Game, Fish and Parks (GF&P) staff began their annual monitoring of the rainbow smelt population in Lake Oahe during April. This includes monitoring spawning adults and growth and distribution of young fish produced this year, losses of fish from the system to predators and reservoir releases during the summer months, and most importantly, population estimates at the end of the summer.
Fisheries Program Administrator Geno Adams said, “Monitoring through lake surveys and angler creel surveys over the next year will help paint a clearer picture of impacts of high water releases in 2011 on reservoir fisheries. We know fish moved through these systems, but to what extent it will affect the sport fisheries remains to be seen.”
GF&P staff began netting for spawning adult rainbow smelt at the beginning of April and finished in early May. Although adult rainbow smelt were caught, the numbers of fish and the length of the spawning run were lower than most previous years. Comparing catches in 2012 to the last ten years suggests that the 2012 spawn was in the lower 1/3rd in terms of the length of the spawning season. Hatching conditions during the egg incubation time frame were mixed. The US Army Corps of Engineers provided a slow increase in the Lake Oahe water level during April. This increase is necessary to keep eggs in shallow water submerged. However, Lake Oahe experienced many high wind events during April. Waves created by wind stir up the bottom in shallow areas, which can damage fragile smelt eggs or deposit silt on top of the eggs, suffocating them. Knowing these factors play a large role in the success of the smelt spawn, GF&P staff will continue to sample for young smelt in Oahe in an effort to determine spawning success.
In addition, a Lake Oahe gizzard shad stocking project is underway. GF&P staff are attempting to bolster Lake Oahe prey fish numbers by stocking adult, pre-spawn gizzard shad this spring. The objective is for these fish to spawn in Oahe, providing sport fish with young gizzard shad as a food resource in localized areas. Past studies have revealed that when abundant, shad are readily eaten by walleye and other Lake Oahe fishes. GF&P staff reached their goal of stocking approximately 1,700 shad early in May. As with rainbow smelt monitoring, GF&P staff will use various tools to monitor the success of the gizzard shad stocking project.
Lake Sharpe
Fishing has remained good on Lake Sharpe through the spring of 2012. However, numerous reports of “skinny” fish have been fielded by South Dakota Game, Fish and Parks (GF&P) staff. Although most of the walleye in Lake Sharpe appear healthy, there are some skinny fish in the system. This is largely due to low gizzard shad production in 2011 caused by the 2011 flood.
During the flood of 2011, water releases through Oahe dam were the highest ever recorded. Because the water intake structures for Oahe Dam are deep below the surface, water released into Lake Sharpe was very cold. In fact, water temperatures last year were10-16oF below normal summer water temperatures. These cool water conditions likely delayed gizzard shad spawning in 2011. Thus, fewer shad were available as food for sport fish through the winter and spring. Because of the high number of rainbow smelt passing through Oahe Dam in 2011, Lake Sharpe sport fish remained healthy through the summer and fall months despite few available gizzard shad. Now that the supply of rainbow smelt from Oahe Dam has been curtailed, the sport fish in Lake Sharpe are beginning to feel the effects of a lower food supply than most years.
However, the effects of low gizzard shad reproduction in 2011 should be short lived. GF&P staff have spent time on Lake Sharpe looking for evidence of gizzard shad spawning, with much success. Initial sampling efforts indicate a strong gizzard shad spawn is taking place on Lake Sharpe. Gizzard shad spawn in shallow water areas close to shore. They are frequently observed at Farm Island in Hipple Lake spawning.
Senior Fisheries Biologist Mark Fincel said, “I have seen first hand gizzard shad spawning on Lake Sharpe and we have begun to catch the larval fish in our surveys. Current weather conditions will likely favor the gizzard shad spawn (warm and sunny) so it is likely the spawn will last a couple more weeks at least. It is only a matter of time before we see those fish in the diets of Lake Sharpe sport fish.”
With a successful gizzard shad spawn on Lake Sharpe, it is likely these fish will become available as food for sport fish by late June. Until the food supply increases and water temperatures warm substantially, we expect fishing to continue to be good on Lake Sharpe.
We always caught “skip jack” growing up, they were common in Oahe and Sharpe. I’m not sure how those fish relate to gizzard shad vs mooneye/goldeye. 
