VENTURA — Thousands of dead carp in Ventura Marsh are going to be allowed to decompose naturally, according to the Iowa Department of Natural Resources.
The carp died when the water level of the marsh was drawn down this winter as part of the recently completed marsh restoration project.
The $5 million marsh restoration included the demolition of the existing outlet structure, construction of a new emergency spillway and a pump station with an outlet to Clear Lake.
The pump was used to draw down the water level which resulted in the fish kill.
“That’s a success story from our standpoint. It’s functioning like we want it to,” said Mike McGhee, lake restoration project coordinator for the Iowa Department of Natural Resources.
The water level in the marsh will be kept low through the entire 2012 summer season and the spring through early summer of 2013 to allow for the growth of aquatic plants, according to DNR fisheries biologist Scott Grummer.
“If the vegetation response is what we hope for then we can start bringing in water gradually onto that vegetation probably from the middle of July 2013 on,” Grummer said.
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McGhee said the DNR wants the aquatic plants to germinate and grow within those bare soil areas of the marsh.
“Those plants need some hardiness and need to establish a root system so you can’t inundate them with water right away,” McGhee said.
Grummer said moving the dead carp would be problematic.
“If we can let Mother Nature take its course, those fish won’t be there very long once we have these warm temperatures,” Grummer said.
“Once we would try to remove them, it sounds odd, but you can’t just go dump them out on top of the ground. They fall under the same criteria like other dead animals like in a hog confinement.”
Carp are part of a class of rough fish which stir up sediment at the bottom of the lake.
Aquatic vegetation helps to absorb nutrients and keep them from getting into the lake.
McGhee said the DNR hopes to cut some canals in the existing vegetation at the upper end of the marsh so water coming from the watershed will meander around before spilling into Clear Lake.