Aquatic invasive species by the numbers

Some local residents around Otter Tail County's Marion Lake worry a public boat landing could be an open door for invasive plants or zebra mussels to enter the lake. They want the authority to raise local taxes to pay for invasive species resistance programs.  MPR News file photo.

The Department of Natural Resources spent about $8.5 million on aquatic invasive species (AIS) programs in 2013. Here’s a breakdown:

-Enforcement – $1,780,000
-Inspections  – $2,200,000
-Inspection equipment  – $270,000
-Public awareness and prevention grants  – $300,000
-AIS management – $1,092,000
-Statewide coordination and field operations – $2,200,000
-Asian Carp planning and monitoring – $93,000
-Lake service provider training – $50,000
-Implement best management practices for water access points – $500,000

The current DNR infested waters list shows 138 lakes, rivers and wetlands infested with zebra mussels. The official list will be updated soon, but the latest information from the DNR’s AIS expert Heidi Wolf,  lists 28 new lakes infested with zebra mussels this year.

There are also a few lakes where DNR aquatic invasive species staff  will look for zebra mussel evidence on  boat lifts and docks as they come out of the water this fall.

Zebra mussels are a focus of AIS efforts because of concerns about how they might affect lake ecosystems,  but there are many other unwanted plants and animals making their way to Minnesota lakes and rivers. There have been seven new infestations of eurasian water milfoil this year and two new infestations of flowering rush. Spiny water fleas are another concern with two new infestations this year and faucet snails are another invasive species finding its way to more lakes.

The DNR uses inspections and checkpoints as tools to enforce aquatic invasive species laws and prevent their spread. The DNR has data on 13 checkpoints it set up this summer.

DNR Enforcement Capt. Cory Palmer says 249 water craft were inspected and 25 percent of the inspections resulted in a violation. That’s about the same as the violation rate found during checkpoints last summer. The checkpoints were held in Crow Wing(2), Le Sueur, Aitkin, Kandiyohi, St. Louis(2) Chisago, Dakota, Olmsted, Douglas, Hennepin and Bigstone counties. Palmer says the decision on checkpoint location depends on local enforcement resources and the availability of safe locations to stop traffic. Palmer pointed out the average stop time for a violator was about nine minutes. The average stop time for a non-violator was three minutes.

The DNR also tracks inspections at lake access points. The data from last year show inspectors spent 62,132 hours conducting 101,794 inspections. That’s about 1.6 inspections per hour. Those inspections took place across the state, with 70 percent targeted at waters infested with aquatic invasive species.

Aquatic invasive species inspectors spent the most time (more than 11,000 hours) monitoring the Mississippi River. Minnetonka, Mille Lacs, Gull and Leech lakes round out the top five most inspected waters with about half of the total inspection hours.

The DNR protocol is to focus inspections on infested waters, and popular non-infested waters that see a lot of boats coming and leaving.

Incidentally, the DNR says a new mobile app that replaces paper forms now allows inspectors to upload inspection results right from the lake access.