HURON – An aeration system was installed in Ravine Lake Tuesday with the goal of boosting oxygen levels and improving the chances for fish survival year-round, the aquatic habitat and access biologist for the state Game, Fish & Parks said.
“This aeration system is very similar to the same type of bubble aerator that is in any household aquarium,” Kip Rounds said.
“The same concept, where you have a compressor and you have air lines going out.”
For years, the volunteer Lake & Riverfront Development Committee has worked to make improvements to the Ravine Lake area. It has become a popular recreation spot today, and the committee continues to take steps to further enhance the attraction.
But the lake as a dependable source for anglers has been hindered by low oxygen levels and fish kills.
“This is going to hopefully alleviate that,” said Marc Fenske, committee chairman, as GF&P staff worked to install the aeration system off the lake’s island.
“We requested help because we want to stock this with good fish,” he said.
In the past, the lake has been stocked with adult catfish, white bass, perch, northerns and walleyes, but it’s unknown what has survived, said LaRon Klock, director of the Huron Parks and Recreation Department.
This year, white bass and walleyes were introduced to the lake, he said.
“There used to be a few bass and crappies, and we’ve had just about everything in there,” Klock said.
In a partnership with the city of Huron, the state GF&P agreed to select Ravine Lake as its second aeration project as part of its work with urban community fisheries. A year ago, the first one was the Outdoor Campus in Sioux Falls.
In 2020, Rounds and his crew will turn their attention to Lake Herman State Park, where there’s a lake of similar size to Ravine Lake.
Rounds said the water body near Madison has many of the same issues that Ravine Lake has experienced. “Fish kills in late summer that we want to try to alleviate so that’s going to be another good candidate for us,” he said.
“We try to stock harvestable-sized fish, catchable-sized fish in these water bodies so there’s an immediate fishery and we do that as an annual stocking,” Rounds said.
“This spring we were here stocking with white bass available from other water bodies,” he said. “We brought them in to create an instant fishery.”
But, of course, stocking lakes can be a frustrating exercise if nothing is done to try to prevent fish kills due to low or no oxygen.
With its aeration system, GF&P is trying to increase the levels of dissolved oxygen in the water column. Drops in oxygen levels during late summer are natural occurrences, Rounds said.
“We’re also trying to prevent the water column from stratifying,” he said. “What these aerators will help do is to keep the water mixed.”
The problem with a shallow water system is that the water column can stratify, meaning higher oxygenated water toward the top of the water column, but low oxygen or no oxygen toward the bottom.
“What we hope this will do is keep that water mixed and prevent stratification so that there’s going to be oxygen throughout the water column, even at the bottom, and that will help prevent those fish kills and create just an overall healthier aquatic ecosystem,” Rounds said.
Stratification in South Dakota lakes is a natural process, especially when there’s not a lot of wave and wind action to mix the water, he said. It’s also particularly true later in the summer when there are higher water temperatures, compounding problems with stress in fish and contributing to kills.
“A big problem that we see late in the summer that often leads to a fish kill is a few days in a row of cloud cover and low wind,” Rounds said.
Also, cloud cover means no sunlight that allows plants, even algae, to photosynthesize and create and increase oxygen in the water.
“When they’re not able to photosynthesize, they start to die off and decompose and when they do that they actually consume oxygen so it’s a compounding effect there, too,” he said.
Low oxygen is an issue in the lake both in summer and winter, Klock said. “We hope that the summer/fall better water conditions will carry over into winter where conditions can keep us in better shape for fish survival.”
Six heavy aerators attached to weighted air lines – which are plugged into compressors on the island – were placed in various areas of the lake between 300 and 600 feet from the island. They will remain in the lake year-round, while the compressors will be removed and stored during the winter months.
Maintenance will be required every few years, but that and the system itself is funded by the state. The only cost to the city is electricity, and with a pair of one-horsepower compressors that will be minimal, Rounds said.
The Lake and Riverfront Development Committee continues to make improvements to Huron’s lake, an attraction that makes the city unique.
“It’s a convenient place for new anglers, especially kids, to come down and fish and so it’s a really high priority for us to manage these urban community fisheries,” Rounds said.