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
