Zebra Mussel Monitoring in the Richelieu River: A Fruitful Interaction between Scientific Research and Public Involvement

Abstract

As part of a collaboration between scientists from Environment Canada and COVABAR (a non-governmental organization), a 4-year study was conducted to monitor the presence, spread and potential impacts of zebra mussels (Dreissena polymorpha) along the Richelieu River. Taking advantage of riverbed cleanups conducted every September, a sampling program was set up to determine the annual colonization and spatial distribution of zebra mussels along the river between 1997 and 2000. A protocol for effective sampling coordination and scientific data acquisition was developed to allow that objects removed from the water be examined and the zebra mussels attached to them be counted and sampled. Results confirmed that the first massive invasion by zebra mussel occurred upstream of the Chambly Basin in 1996 and two years later at downstream sites. Size distribution of zebra mussels varied between years and sites which suggested strong variability in recruitment patterns along the river. This variability could be due to inter-annual variation in river discharge during summertime. Colonization rate of unionids by zebra mussels was still low in these early years of colonization in the river. It is recommended that a long term sampling program coupled with specific ecological studies be conducted in order to assess the abundance and impacts of zebra mussels in the Richelieu River. Sampling responsibility for such monitoring should be transferred to non-governmental organization in order to increase public awareness to the problem of exotic species and biodiversity.