From the DNR news releases yesterday.
Forwarded by Jane Clark

Adult Zebra Mussels Found on Boat at Lake Rathbun

MORAVIA - An estimated 100 adult zebra mussels were discovered on a cabin 
cruiser last Friday that had been moored at a marina on Lake Rathbun since 
late June.  State officials stress that it is too early to tell if the 
exotic mussel has established a foothold in the 11,000 acre reservoir, but 
they are taking appropriate precautions.

The Iowa Department of Natural Resources (DNR) will be monitoring the marina 
and other areas around the lake over the next few years looking for the 
presence of juvenile zebra mussels, called veligers.

It is illegal to possess or transport prohibited aquatic invasive species 
such as zebra mussels in Iowa.  Signs are posted at public accesses to 
identify infested waters.  The DNR will be working with the US Army Corps of 
Engineers to place signs alerting boaters of the potential presence of zebra 
mussels in Lake Rathbun and to help stop the spread of other aquatic 
nuisance species.

"We cannot allow the careless behavior by a few individuals and businesses 
to permanently impact a resource used by 800,000 visitors.  If these zebra 
mussels become established here, there is no permanent fix, we will have to 
learn how to live with this changed ecosystem," said Richard Leopold, 
director of the Iowa DNR.  "We are looking at any and all enforcement 
options.  Ignorance and carelessness is not an excuse."

The discovery has alarmed local, state and federal officials who rely on the 
south central Iowa reservoir to provide drinking water, water for an 
important fish hatchery, fishing, boating and other recreation.  Lake 
Rathbun generates millions of dollars for the local economy and is the site 
of the $50 million Honey Creek Resort State Park.

Zebra mussels grow to only two or three inches at the largest and live for 
up to three years.  They can spawn within the first year of life and each 
mussel can produce up to 1 million young and spawn multiple times per year.

Zebra mussels are filter feeders and directly compete with native species, 
including mussels and fish fry.  Zebra mussels adhere to hard objects and 
once attached, they usually stay for life.  If the densities are high 
enough, they can smother native mussels by attaching to their shells and can 
out compete native filter feeding organisms.

Lake Rathbun provides water for the Rathbun Regional Water Association which 
serves an estimated 70,000 people in southern Iowa and northern Missouri. 
Zebra mussels can impact water supplies by clogging water intake pipes and 
requiring millions of dollars for treatment.  Their microscopic larvae can 
pass through many screens intended to keep them out. Millions of dollars are 
being spent annually by Great Lakes cities and industries to unclog intake 
pipes and prevent further infestation

Lake Rathbun is also one of the Iowa DNR's walleye collection lakes and 
raises walleyes and channel catfish that are stocked over much of the state. 
The lake empties into the Chariton River, which is a tributary of the 
Missouri River.

"It's going to create a lot of headaches in transporting and stocking fish," 
said Andy Moore, who supervises hatchery operations at the Rathbun Fish 
Hatchery.  Moore said upon discovery, the DNR suspended walleye stocking. 
He said they will begin treating the water to make sure the hatchery does 
not transport any zebra mussel or mussel larvae to any other Iowa water 
body.

"This is an existing treatment that we use at our Fairport Hatchery, but we 
just don't know the impact it will have on these larger walleye 
 fingerlings," Moore said.  It will take about three days to complete the 
test. The decision on when to resume stocking is pending.  "We know the 
treatment works.  But what we are looking for is any delayed fish 
 mortality."

The impact to the lake itself is unclear.

"We don't know if these things have a toe hold yet or not," said Mark 
Flammang, fisheries management biologist for Lake Rathbun.  "We are treating 
the lake like it does have a zebra mussel population and we are going to do 
everything we can to ensure that we don't move any mussels from this lake."

An estimated 800,000 people visit Lake Rathbun each year for fishing, water 
skiing, boating and camping.  The lake has a reputation for tremendous 
walleye, crappie and channel catfish fishing and draws anglers from 
Illinois, Wisconsin, Missouri and Nebraska as well as all over Iowa.

"I hope we dodge this bullet," Flammang said.  "But we won't know for a few 
years."

The incident remains under investigation.

Sidebar: Stopping Spread of Zebra Mussels
With such a mobile society, it will take a constant effort to get the word 
out to anglers and boaters to help prevent the spread of zebra mussels, said 
Kim Bogenschutz, aquatic invasive species coordinator for the Iowa 
Department of Natural Resources.

Zebra mussels were first documented in the Mississippi River in Iowa in 
1992. There were no reports of zebra mussels from interior waters until 2005 
when they were found in Clear Lake. The next example of zebra mussels on the 
move in Iowa occurred in 2006 when zebra mussels were discovered in Lake 
Delhi.

Bogenschutz has been working with individual boaters about inspecting their 
vessels, and will be stepping up her efforts to work with boat dealers and 
marinas on education.

"For boats that are put in and taken out daily, the critical thing is to 
drain the live well and other water from the boat, because it would be more 
likely those vessels would collect veligers in their live well, than have 
adult mussels attached to their hull," Bogenschutz said.

She said each time boaters pull their boat from the water, there are a few 
easy things they can do to protect other water bodies.

Remove any visible plants, animals, or mud before transporting equipment.
Drain water from all equipment (motor, live well, bilge, transom well) 
before transporting.
Clean and dry anything that comes into contact with water (boats, trailers, 
equipment, boots, clothing, dogs).  Before transporting to another waterbody 
either:
Rinse your boat and equipment with hot (104 degree) water; or
Spray your boat and trailer with high-pressure water at a carwash; 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.

Zebra mussels are one example of an aquatic invasive species that has 
hitchhiked its way into Iowa.  More information about aquatic invasive 
species and a list of infested waters can be found in the Iowa Fishing 
Regulations booklet and on line at www.iowadnr.gov/fish then click on 
Aquatic Nuisance Species in the left hand column under the programs section.

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