PIERRE, S.D.(WNAX)- The South Dakota Game Fish & Parks Department plans another aggressive campaign to slow down the spread of aquatic invasive species, focused on zebra mussels.

Fisheries biologist Jake Davis told the Game, Fish & Parks Commission they have a simple message.

Davis says they are seeing good results from the campaign.

Davis says their operational plan will change from year to year.

Davis says they will also focus on filling a number of job vacancies related to the boat inspection program.

Over forty bodies of water in the state have some level of zebra mussel infestation.