Recently, some in the local fishing community have hinted that the alewife might be a positive thing for Lake Champlain. From our viewpoint, the science does not seem to back up this idea. In fact, there is plenty of evidence that invasive species in general and Alewife in particular are not a welcome invader in freshwater systems.

Alewives are very likely to restructure Lake Champlain's food web in a negative way, by reducing native fishes and consuming native zooplankton, their primary food source. Alewives will certainly displace smelt, the predominant native forage fish in Lake Champlain, from its ecological niche space by reducing the smelt's habitat and food resources.

While some will claim the fishery may improve with the addition of alewives in the lake, there is mounting scientific evidence to the contrary. Alewives, in fact, are known to cause a severe thiamine deficiency in Atlantic salmon, resulting in major impacts to the salmonid fishery. This problem has already manifested itself with the Lake Champlain salmon stocking program.

Another example of how invasive species are not good would be the spiny waterflea, which is at the door of Lake Champlain in New York. The spiny waterflea was recently found in Sacandaga Lake. If this invasive exotic ever gets into Lake Champlain, it will further erode the balance of the planktonic food web, most likely to a point of no return. Most of a spiny waterflea's body consists of a very long spine, making it a poor food source for fish. This allows the waterflea to establish large populations and out-compete the native pelagic plankton. The result is most assuredly a decline in native zooplankton, which play a pivotal role in the food web that supports the fishery we all want to maintain. Research conducted at SUNY Plattsburgh has already shown the negative impacts that invasive species can have on the lake, with a restructuring of the planktonic food web in the mid 1990s during the zebra-mussel invasion.

Along with the impending spiny waterflea, other examples include Eurasian milfoil, Japanese knotweed and water chestnut, to name just a few non-native invasive species already established in the lake threatening the ecological roles of native species.

It has taken thousands of years for Lake Champlain to develop into a wonderfully balanced ecosystem, and it may only take a few decades for human-induced species invasions to destroy it. So, just to clarify, invasive exotic species are rarely a positive thing for the natural ecological balance in the ecosystems they invade. Just ask the people dealing with the current emerald ash borer invasion into our region's forest.

The staff at the Lake Champlain Research Institute at SUNY Plattsburgh contributed to and/or endorsed this opinion. It includes Casey Binggeli, Erin Bradshaw, Bonnie Phillips, Amanda Groves, Jeffry Jones and Mark Malchoff (Lake Champlain Sea Grant).