"Mistaken ideas about the spread of AIS"

In connection with recent discussions about Aquatic Invasive Species (AIS) and what to do about them, I’ve recently overheard some comments from local public officials and others  that suggest that there are some misunderstandings about aquatic invasive species (AIS), and the risks of further AIS infestations.     

There are many ways that AIS is spread?   Why should we focus on watercraft?     Nearly all modern infestations of AIS are caused by the movement of boats carrying AIS from infested water.   The movement of waterfront equipment from one lake can spread AIS, but the risk is much less because of low frequencies of such movements, Over 95% of all equipment (boat lifts, docks, etc)  installed in area lakes has never been in another lake, and therefore carries no risk of carrying new AIS to the lake.  The DNR requires a 21 day waiting period before moving such objects from lake to lake.   Also, research has shown that water waterfowl are not considered a significant mechanism for spreading AIS.

Most AIS is spread by riparian property owners because they bring so many boats to a lake.   Riparian residents do not pose a high risk of infesting their own lake because the vast majority of their boat launches occur once per season or repetitive launches involving the same lake. 
  

But many property owners have their own private accesses and no one inspects them.  Few private accesses are capable of handling modern fishing or pontoon boats.   Private launches typically are used to launch canoes or small boats which remain on a single lake.   Nearly all lakes have public accesses,  and the usage of public accesses is about 96% of the total launches on such lakes.   On some lakes commercial launching facilities are popular - these typically receive the same scrutiny as public launch sites.

Lakeshore property owners introduced Flowering Rush into our lakes.   True! Flowering Rush was intentionally introduced into Curfman lake in the mid-1970’s.  At that time, it was perfectly legal and seemed to be reasonable to use Flowering Rush for landscaping purposes.    The Flowering Rush case does not inform the discussion of the current AIS threats which are both known and illegal.   Moreover, in part because of the Flowering Rush story  ( lakeshore property owners have paid most of the costs of flowering rush treatment) these  property owners are well-informed on the hazards of  introducing invasive species, and are extremely unlikely to participate in their spread.. 

All the efforts to halt the spread of Zebra Mussels are futile and a waste of resources – all lakes will eventually be infested.    In all likelihood Zebra Mussels will be found in more lakes, and very possibly in lots more.    It is noteworthy that inspections and education do seem to have an impact - But there are some very good reasons to resist the spread of Zebras – perhaps we will be one of the lucky areas to escape.   Or perhaps we can slow the spread to give scientists an opportunity to come up with a solution.   Most importantly, there are many different AIS problems out there, so approaches for slowing or stopping the Zebra Mussel are the same ones to be used to avoid other AIS invasions too.   And some of those, Eurasian Water Milfoil as one example, would require costly treatments.       

Dick Hecock
Lake Detroiters Environmental Chair