Invasive Species Threats

Lake Champlain has roughly only half as many invasive species in comparison to the Hudson and St. Lawrence Rivers. The Great Lakes on the other had have almost four times more invasive species then Lake Champlain. This is causing major concern in the Lake Champlain basin because of the fact that Lake Champlain is connected to all of these invasive species plagued water entities. Opening Lake Champlain up to a variety of new species with unknown consequences.

Found at: http://lcbp.wordpress.com/2009/12/02/what-is-the-%E2%80%9Clatest%E2%80%9D-aquatic-invasive-plant-or-animal-that-appears-to-be-heading-for-lake-champlain/. Accessed on: 29 March 2012

Control of Zebra Mussels

As previously mentioned throughout this blog Zebra mussels (Dreisenna polymorpha) were introduced in to the great lakes in 1986, and eventually Lake Champlain in 1993, through the release of ballast water (Ludyanksiy 1993).  They cause adverse effects to the ecology and health of the lake system including degradation of Lake trout spawning area, competition with small and larval fish for plantonic resources, and the killing of the lakes native mussels.  Not only does this nuisance species affect animals but people as well.  The edges of the Zebra mussel are incredibly sharp and able to easily slice human skin.  Some of our favorite swimming spots have become colonized by these invaders, making them hazardous to our well being.

Some view education as the only way to curb the attack of Zebra mussels, but several studies have tested more radical solutions to the problem. Claudi (1994) conducted experiments involving the establishment of Zebra mussel larvae of objects such as pipes (a common occurrence that can effectively block flow).  He found that by applying copper to the inside surfaces larval settlement could effectively be reduced.  Other studies found that applying molluscacides, such as Cutrine Ultra, to water systems can potentially help decrease the amount of Zebra mussel larva, as this is the most sensitive life stage to changes in chemical balance (Kennedy 2006).

While the introduction of chemicals into our watershed may seem a viable option for Zebra mussel eradication, it does not come easy.  Chemicals often do not target a single species, and have the ability to effect any organism that comes in contact with it.  This should be taken into consideration when discussing the most effective way to curve and eventually remove the Zebra mussel population

Claudi, R., Mackie, G.L. (1994) Practical Manual for Zebra Mussel Monitoring and Control.  Florida: CRC Press

Kennedy, A.J. (2006) Relative Sensitivity of Zebra Mussel (Dreissena polymorpha) Life-stages to Two Copper Sources. Journal of Great Lakes Research 32(3):596-606

Ludyanksiy, M.L., McDonald, D., Macneill, D. (1993) Impact of a Zebra Mussel, A Bivalve invader. Bioscience. 43(8): 533-544

Alewives

 

     Alewives migrate into freshwater from the ocean to spawn, but can stay and survive in freshwater.  They have been a problem in Lake Champlain, after their introduction in 2003, because they compete with native fish species and eat eggs of other fish.  They also provide an insufficient diet for Lake Trout and Atlantic Salmon, causing a decline in native species. Some practices for control used in the Great Lakes, that could also be used in Lake Champlain, would be the introduction of a predator species, such as Chinook salmon and steelhead/rainbow trout.  These fish also provide fun for anglers, as Chinook salmon can become quite large in size.
     One of the larger effects of Alewives on Lake Champlain is its destruction of the zooplankton community.  Since Alewives main food source is the zooplankton, they can cause a drop in zooplankton numbers, which in turn can effect the inner workings of the lake.  By eating large amounts of zooplankton, algal blooms can occur because their are not enough zooplankton to keep algae in check.  Water clarity and and nutrient dynamics of the Lake are then altered from the algal blooms.
     Alewives, as stated before, can cause a large problem when they feed on the eggs of native fish, such as the Lake Trout.  Feeding on the eggs can be a bigger problem than food competition, and can cause mass mortality in native fish.  In a study of Lake Ontario, Alewives were found to cause a 100% mortality in Lake Trout fry in near-shore regions where Alewives were common.  If Alewives are not controlled and monitored, Lake Trout in Lake Champlain may see the same fate.
Looking at the map to the left, one can see the red areas around the Lake Champlain basin, showing that Alewives have been introduced to our area.  On the map one can see how they are native to coastal areas since they only come into freshwater to spawn, but now they have made it far upstream and become invasive in areas including Lake Champlain.
Map from: http://www.greatlakesfisherman.com/gallery/files/1/alewiferange.gif

"Vermont Lakes and Ponds- Alewife." Vermont Dept. of Environmental Conservation. N.p.

,Nov. 2011.Web. 11 Apr. 2012. <http://www.anr.state.vt.us/dec/waterq/lakes/htm/ans

/lp_alewife.htm>.