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Zebra mussels found in Carter Lake

The Iowa Department of Natural Resources (DNR) is watching Carter Lake after juvenile zebra mussels were recently found in a water sample collected by Nebraska Game and Parks Commission (NGPC) staff. Although veligers were detected, intensive sampling the past week did not find any adult zebra mussels.

Carter Lake, a border water, is jointly managed by the Iowa DNR and NGPC. The Iowa DNR and NGPC collect water samples and deploy settlement samples in lakes across each state every summer to monitor for the invasive zebra mussel.

Water samples have been collected twice a month in Carter Lake since May.  Additional samples are waiting to be analyzed.  The DNR and NGPC will closely monitor Carter Lake this summer and fall to determine if it has an established population of zebra mussels.

“Finding zebra mussel veligers indicates to us that zebra mussels have been introduced into Carter Lake,” said Kim Bogenschutz, the Iowa DNR’s Aquatic Invasive Species Program Coordinator. “But, it’s too early to tell if there is an established population in the lake.”

Zebra mussels look like small, D-shaped clams that have alternating light and dark bands. Most are less than one inch long. They are filter feeders that can form dense clusters as they attach to hard underwater surfaces.  Large infestations may interfere with aquatic food chains, kill native mussels, clog water intakes, increase algae blooms, and cover beaches with dead shells.  There is no effective treatment to control zebra mussels once they have infested a lake.

The Missouri River has an expanding zebra mussel population along its entire length downstream of Gavins Point Dam.  Other known populations within Iowa include Clear Lake, the Okoboji chain of lakes, and the Mississippi River.

Zebra mussel veligers are microscopic and can be unintentionally transported with water in bilges, live wells or bait buckets.  Adult zebra mussels can attach to boats, trailers and aquatic vegetation. Boats using both the Missouri River and Carter Lake are a probable source of introduction.

It is illegal to possess or transport prohibited aquatic invasive species, such as zebra mussels, in Iowa. Boaters must also drain all water from boats and equipment before they leave a water access and must keep drain plugs removed or opened during transport.

“Boaters and anglers can unintentionally spread zebra mussels and other aquatic invasive species if they do not take the proper precautions - clean, drain, dry - after each time out on the water,” said Bogenschutz.

  • CLEAN any plants, animals or mud from boat and equipment before you leave a water body.
  • DRAIN water from all equipment (motor, live well, bilge, transom well, bait bucket) before you leave a water body.
  • DRY anything that comes into contact with water (boats, trailers, equipment, boots, clothing, dogs). Before you move to another waterbody either:
  • Spray your boat and trailer with hot, high-pressure water; or
  • Dry your boat and equipment for at least 5 days.
  • Never release plants, fish or animals into a water body unless they came out of that water body and empty unwanted bait in the trash.

Find more information about aquatic invasive species and a list of infested waters in the 2017 Iowa Fishing Regulations booklet.

If you see a zebra mussel, please note its location and contact your local fisheries office or the Aquatic Invasive Species Program in Boone.

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