A new review paper whose authors include University of Guelph biologists discusses tradeoffs and possible economic or environmental costs of removing dams or creating fishways, an increasingly popular option among resource managers.
The paper was published online this month in the journal Fish and Fisheries.
“There’s a large push for new fish passageways and dam removal,” said Rob McLaughlin, a professor in the Department of Integrative Biology and the paper’s lead author.
He and former master’s student Eric Smyth worked with fisheries scientists in Michigan, Massachusetts, Ontario and British Columbia.
More resource managers are looking to fishways and dam removal to help build up migratory fish populations and to restore stream biodiversity and natural ecosystems.
Referring to fish and invertebrates that can harm native or desirable fish, McLaughlin said,
“The reality is that dams can be good if they’re blocking aquatic invasive species. There’s a need for a more nuanced approach as opposed to a bandwagon, one-size-fits-all approach to the problem.”
The team looked at almost 200 research publications involving more than 40 fish species and numerous dam locations across North America, Europe and Australia. Their paper discusses tradeoffs and effects of dam removal and fishway construction on various species, and ways to assess costs, benefits and tradeoffs.
The authors highlight an example involving invasive sea lamprey, highly prized walleye, and endangered lake sturgeon and northern brook lamprey at the Black Sturgeon dam in northern Lake Superior.
Smyth studied the Black Sturgeon River for his master’s thesis at Guelph. Referring to competing interests from sport fishers to environmental groups to government agencies, he said,
“There is no simple way to resolve the tradeoffs. No matter what, there’s going to be some negative consequences to management.”
Around the Great Lakes, a number of dams were built initially to control water levels and later modified to thwart sea lamprey. These parasitic fish entered the Great Lakes in the early 20th century.
Canada and the United States created the Great Lakes Fishery Commission (GLFC) to control sea lamprey. McLaughlin has worked with the GLFC on lamprey control, and came to Guelph in 2002 under a GLFC-funded ecosystem program.