Aquatic Invasive Species in Iowa:Current and Emerging Threats

Kim BogenschutzIowa Department of Natural ResourcesAquatic Invasive Species Program Coordinator

What are Aquatic Invasive Species?

Aquatic invasive species are nonnative wildlife or plant species that have been determined by the Department to pose a significant threat to the aquatic resources or water infrastructure of the state.

Invasive Aquatic Plants

• Eurasian watermilfoil• Brittle Naiad• Curlyleaf Pondweed• Purple Loosestrife• Flowering Rush• Salt Cedar• Federal Aquatic Noxious Weeds

Eurasian Watermilfoil

• First identified in Iowa in 1993• 12-21 pairs of leaflets• Fragile appearance - leaves

collapse against stem when removed from water

• Reproduces primarily by fragmentation

Eurasian Watermilfoil Infestations in Iowa through 2016

Anderson Prairie Pond

Sportsman Recreation Area PondSiems Park Ponds

St. Benedicts Pits

Crystal LakeRudd Lake

Airport Lake

Beeds Lake

Wilson Grove PondSweet Marsh

Mitchell Avenue Pit

South Prairie LakeGrundy County Lake

Koutny PondSnyder Bend

Walnut Acres Campground Pond

Horseshoe Pond

Maxwell Pond

Camp Sunnyside Pond

Mississippi River

Red Rock Pond

Mile Hill LakeKeg Creek Lake

Scott Lakes

Walnut Creek Marsh

Ottumwa Pond

Plainfield Lake

Meier Wildlife Refuge

Fogle Lake

Floyd CCB Pond

Percival Lake

Pinky’s Glen

Mill Creek Lake

Jennett Pond

Carter Lake

Blue Pit

Brushy Creek Lake

Brittle Naiad

• First identified in Iowa in 2003• Stems highly branched, crowded terminal nodes• Leaves opposite, recurved,prominent marginal teeth• Reproduces by fragmentation and seeds

Brittle Naiad Infestations in Iowa through 2016

Don Williams Lake

Arrowhead, Black Hawk Slough

Slip Bluff LakeNiine Eagles Lake

Prairie Rose Lake

Springbrook Lake

Pine Lakes

Central Park Lake

Curlyleaf Pondweed

• First identified in Iowa in 1930’s• Reddish-green, wavy, alternate

leaves with finely toothed margins

• Reproduces through turions(hard, burr-like buds)

• Grows early in spring and generally dies by mid-July

Iowa Counties with Curlyleaf Pondweed Infestations

Snyder Bend

Purple Loosestrife

• Unknown when first identified in Iowa• Plant height 2-7 feet• Linear leaves with smooth edges,

usually opposite• Long spikes of purple or magenta

flowers with 5-6 petals• Flowers in July and August• Reproduces by seeds and rhizomes

Iowa Counties with Purple Loosestrife Infestations

Flowering Rush

• First observed in Iowa in 2009• Umbrella-shaped clusters of

whitish pink flowers with 3 petals• Green triangular stems• Erect emergent leaves, tips may

spirally twist• Reproduces by seeds, rhizomes,

and bulbils (small bulbs)

Salt Cedar• First Identified in Iowa in 2000• Deciduous shrubs or trees 10-15 feet tall• Spikes of pink or white flowers at branch tips• Gray-green, scale-like leaves about 1/16 inch long• Brownish purple, ridged, furrowed bark on older

plants• Reproduces by seeds and resprouting

Brazilian Waterweed• First identified in Iowa in 2017• Whorls of 4 or more spear-shaped leaves with

minutely-toothed edges• Usually rooted but can be free-floating• Only male plants in U.S.; reproduces by

fragmentation

Hydrilla

• Identified in Missouri in 2012• Long stems that branch at the

surface• Whorls of 4 or more spear-shaped

leaves with coarse teeth along the edges and midrib

• Reproduces primarily by fragmentation, turions, and tubers

Starry Stonewort

• Identified in Minnesota in 2015• Stems bright green and smooth• Star-shaped white bulbils attached to

clear, root-like filaments• Length of branchlets highly variable

on a single plant• Only male plants in U.S.; reproduces

by fragmentation and bulbils

Invasive Aquatic Plant Impacts• Displace native aquatic and riparian vegetation

and wildlife habitat • Dense growth restricts boating, water-skiing,

fishing, and other recreation• Typically spread from lake to lake by watercraft

and/or trailers

Invasive Aquatic PlantControl and Management

• Prevention• Physical

– harvest– dewatering– water dyes

• Chemical– fluridone, diquat,

triclopyr• Biological

Invasive Aquatic Invertebrates

• Zebra Mussel*• Quagga Mussel*• Rusty Crayfish*• Fishhook Waterflea• New Zealand Mudsnail• Spiny Water Flea• Federal Injurious Aquatic Wildlife

*Located in Iowa

Zebra Mussel

• First identified in Iowa in 1992• Yellow and/or brown D-shaped

shells up to 2 inches long with alternating light and dark bands

• Usually grow in clusters containing numerous individuals

• Each female can produce up to 1 million eggs; veligers are free swimming and stay in the water column for 2-4 weeks

Zebra Mussel Distribution in Iowa through 2016

Clear LakeRudd Lake

Bluebill Lake

Lake Delhi

Lake Cornelia

Blue Pit

Lake Macbride

Brushy Creek Lake

Clear Lake Zebra Mussel Population Growth

2006 2007 2008Sites w/ ZM 5 10 10No. adult ZM 1 210 10,000’sNo. juvenile ZM 12 1,000’s TNC% structures w/ ZM 5 >90 100

Zebra Mussels in Lake Rathbun?

Zebra Mussel Impacts

• Clog pipes• Hamper boating• Foul beaches• Kill native mussels, plants,

crayfish, etc.• Compete with small fish

and native mussels for food

Zebra Mussel Control and Management

• Prevention• Mechanical/Physical

– dewatering• Chemical

– molluscides– chlorine, ozone, radiation– potassium chloride (potash)– copper sulfate

• Biological– Zequanox– micromatrix/biobullets

Rusty Crayfish• First reported in Iowa in 1979 but may have been

misidentified; confirmed in 2002 • Grayish-green body usually 3-5 inches long with pair

of rust-colored spots on carapace (back)• Large, black-tipped claws with oval gap when closed• Displace native species, reduce native plant

abundance and diversity, hybridize with native crayfish

Invasive Aquatic Fish

• Bighead Carp*• Silver Carp*• Black Carp• White Perch* • Round Goby• Rudd• Ruffe• Federal Injurious Aquatic Wildlife

*Located in Iowa

Bighead and Silver Carp

• First identified in Iowa in 1995• Deep, laterally-compressed body with tiny scales• Large mouth without teeth• Eyes far forward and project downward• Reproduction only known from rivers

Asian Carp Distribution in Iowa through 2016

Bighead and Silver Carp Impacts

• Compete with native filter-feeders (paddlefish, buffalo, mussels, larval fish)

• Disrupt commercial fishing for more profitable species

• Disrupt water recreation

Asian Carp Control and Management

• Prevention• Barriers

– dams– electric

• Experimental techniques– carbon dioxide– complex sound– micromatrix piscicide delivery– pheromones

• Harvest

Iowa Great Lakes Asian Carp Barrier

Black Carp

• First identified in the Mississippi River in Illinois and Missouri in 2004

• Long narrow body, brown to black along the spine fading to white along the belly with a gold sheen

• Large, dark-edged scales• Reproduction only known from rivers• May reduce native mussel and snail populations

Northern Snakehead• Identified in White River (Arkansas) in 2008 and

Mississippi River (Mississippi) in 2017• Torpedo-shaped body up to 33 inches, tan body

with dark brown mottling• Long dorsal and anal fins• Can survive days out of water; overland migration

possible by juveniles• May compete with native species for food and

habitat

Presenter

Presentation Notes

aggressive aquarium fish Resembles bowfin but bowfin have black spot at base of tail, short anal fin, pelvic fins at mid-body, and no scales on head.

Aquatic Invasive Species Program Activities

• Public Outreach• Vegetation and Zebra Mussel Surveys• Monitoring of Asian Carp Populations• Control and Management of Aquatic Invasive

Species Infestations• Watercraft Inspections

AIS Program Funding and Staff

• $650,000 budget - boat registration fees (increased revenues from Boat Registration Act of 2005 is split between boating safety and AIS), federal grant, Fish and Game Protection Fund (Trust Fund)

• 1 Full-time Natural Resources Biologist• 1 Full-time Natural Resources Technician• Up to 20 Seasonal Aides

Public Outreach Methods

Monitoring the Spread of AIS

• Vegetation Surveys• Zebra Mussel Surveys

– Hard structure surveys– Settlement samplers– Veliger sampling

• Bighead and Silver Carp Distribution

Invasive Plant Surveys

Zebra Mussel Monitoring

Asian Carp Surveys

Iowa Watercraft Inspection Results

Knowledge of 2001 2016Invasive species 51% 92%Eurasian watermilfoil 46% 68%Zebra mussels 50% 93%Asian carp na 93%Brittle naiad na 40%AIS law 25% 90%

Boats with Species Attached(8,209 Boats Inspected in 2016)

None 7,615 (93%)Eurasian watermilfoil 4Brittle naiad 2Zebra mussels 3Curlyleaf pondweed 160Vegetation/other 426

Preventing the Spread of AIS• CLEAN any plants, animals, or mud from boat and

equipment before leaving a waterbody.• DRAIN water from all equipment (motor, live well, bilge,

transom well, bait bucket) before leaving a waterbody.• DRY anything that comes into contact with water (boats,

trailers, equipment, boots, dogs). Before transporting to another waterbody either:– Spray boat and equipment with hot, high-pressure water;

or– Dry boat and equipment for at least 5 days.

• Never release plants, fish, or animals into a waterbody unless they came out of that waterbody and empty unwanted bait in the trash.

Kim BogenschutzKim.Bogenschutz@dnr.iowa.gov

www.iowadnr.gov/ais515-432-2823

Aquatic Invasive Species Law(Iowa Code 456A.37)

• Aquatic invasive species (AIS) are identified and designated by the Iowa DNR

• Prohibitions:– A person shall not transport on a public road or

place into waters of the state any water-related equipment that has an AIS or aquatic plant attached or within ($500 fine)

– A person shall drain all water from water-related equipment when leaving waters of the state. Drain plugs, valves, etc. shall be removed or opened while transporting water-related equipment ($75 fine)

Aquatic Invasive Rule(Iowa Administrative Code 571 Chapter 90)

• Rule lists prohibited aquatic invasive species• “A person shall not possess, introduce, import,

purchase, sell, barter, propagate, or transport AIS in any form in this state” with exceptions including:– disposal as part of harvest or control– transported in a sealed container to be identified– caught by angler and returned to water or

immediately killed