SIOUX FALLS, S.D. – Mentioning the word "siphon" today would likely have one think of stealing gasoline from a motor vehicle. But for Game, Fish and Parks fisheries staff, the word means good intentions for Lake Alvin.

Fisheries officials from Sioux Falls will be siphoning Lake Alvin during the week of Oct. 3 to test a method of improving fish populations. They will use up to 50, 3-inch diameter siphon hoses to lower Lake Alvin’s water level by one foot.

The objective of the operation is to test the equipment, labor and logistics needed to lower the lake three feet next spring. The technique is called "drawdown" and can be an effective method for improving fish populations.

"Lake Alvin has always had good numbers of crappies and bluegills but they rarely get large enough to interest many anglers, " said Todd St. Sauver, GFP regional fisheries manager in Sioux Falls. "In addition, we have trouble maintaining a good largemouth bass population because the lake lacks the critical habitat, in this case, submerged aquatic vegetation, which is needed for successful fish reproduction and recruitment."

On the other hand, Lake Lakota, located In nearby Newton Hills State Park, contains excellent populations of good-sized crappies, bluegills, perch and bass, and the lake is full of aquatic vegetation. What is the difference? The dam at Lake Lakota leaks, and the water levels are constantly going up and down, depending on rainfall amounts.

A study conducted this summer by SDSU professor Steve Chipps and GFP Fisheries Biologists Dave Lucchesi and Bruce Johnson found that Lake Lakota contains many times more aquatic invertebrates (insects, crustaceans and snails) than Alvin. Aquatic invertebrates are very important food items for panfish, and young predators and thrive when there is plenty of aquatic vegetation to hide in.

"If next week’s test is successful, we plan to lower Lake Alvin three feet next spring and keep it lowered until next fall, "St. Sauver said. "This will expose about 30 acres of the lake bottom. During the summer, vegetation will grow on the exposed bottom, and when the lake refills the following spring, this vegetation will become ideal habitat for fish and aquatic invertebrates. With better habitat and more food, we hope to see an increase in the average size of the panfish and better largemouth bass reproduction."

When South Dakota B.A.S.S. Federation (SD BASS) President Kyle Helseth and Environmental Director Phil Risnes were informed about the project, they enthusiastically offered the Federation’s help in the form of a check for $1,000 to purchase the siphon hose.

"The SD B.A.S.S. Federation is happy to assist GFP with their efforts to improve all fishing in South Dakota, "President Helseth said. "If this technique works on Lake Alvin, it could be used on other small impoundments throughout the state that have similar problems."

The swimming beach and boat ramp in the Lake Alvin Recreation Area is expected to remain useable throughout the duration of the project.

-GFP-