Acadia prof questions reality of fish-friendly turbines

Wendy Elliott
Published on October 11, 2014

Dr. Mike Dadswell responds to a question following his talk at Acadia University on Oct. 9. 

©Wendy Elliott

WOLFVILLE - Dr. Mike J. Dadswell doesn’t mince words or science. He says there is no such thing as a ‘fish-friendly’ hydroelectric turbine – and goes one step further and asks why Nova Scotia would risk collapsing a $100 million fishery.

Dadswell, a retired biologist at Acadia University, has been studying the effects of hydraulic turbines on fish near the power plant at Annapolis Royal since the 1980s. On Oct. 9, he held a talk presented by the Acadia Biology Seminar Series.

Dadswell was taught the engineering principles by early proponent George Baker, director of the Nova Scotia Tidal Power Corporation, who also personally funded two years of research on fish mortality at Annapolis Royal.

At his lecture, Dadswell explained how fish migrate around the upper Bay of Fundy region seasonally. Back in the early 1970s, a lack of research suggested the area was devoid of organisms, he said.

When he began working for the federal department of fisheries in 1979, “We discovered a nursery for shad in the area.”

There were salmon, sturgeon, striped bass, shark, flounder and haddock stocks as well.

According to Dadswell, between 1840 and 1900, the wealth of fish in the bay was well known, but “everyone forgot.”

All the larger species, he said, “are toast in hydroelectric turbines.”

Sharks, he added, would have almost 100 per cent mortality with a turbine “smack in the middle of their migration path.”

Dadswell showed photos from his research in 1985 in Annapolis Royal, at a facility he described as being “nice” if it didn’t have side effects, such as fish kill.


Scott’s Bay project

There is one turbine at Annapolis Royal currently and Dadswell pointed out that the Halcyon/Scott’s Bay Tidal Power Ltd. project could have 304 turbines.

“They believe it’s not a barrage, but it is a barrage,” he said of the project.

The Scott’s Bay Tidal Power Ltd. is a Nova Scotia arm of Halcyon Tidal Power, an American power company.

The firm has called the project the world’s first environmentally responsible tidal range power project. The $3.2 billion tidal range the company hopes to construct would stretch 10 kilometres from Baxter’s Harbour to Cape Split and will sit six metres above the water at high tide.

The blades of the Halcyon project will operate on the ebb and flow of the tides as well at Scott’s Bay, while Annapolis Royal only functions on the falling tide, Dadswell said.

He used images of dead fish to demonstrate how turbines can kill four different ways. The design planned for Scott’s Bay, he added, “turns really fast. They’re basically killer turbines.”

In addition, he said, the site planned for the barrage is lobster habitat.

“DFO should be screaming their heads off,” Dadswell said, adding that various species collect in Scott’s Bay away from the furious tides in the Minas Passage.

In response to a question about whether the Scott’s Bay project is a done deal, Dadswell said the environmental impact studies have not begun. He said he was on sabbatical last year when the news broke about Halcyon’s interest and he hasn’t spoken out until now.

In response to a question about whether the Scott’s Bay project is a done deal, Dadswell said the environmental impact studies have not begun. He said he was on sabbatical last year when the news broke about Halcyon’s interest and hasn’t spoken out until now.


Fish losses

The population of striped bass has crashed in the Annapolis River due to the turbine in that area, Dadswell said, and he fears open ocean tidal projects will be an even bigger problem.

“Why sacrifice one renewable resource for another?”

Dadswell asked.

A fisherman in the audience added that tidal detrius, such as seaweed and broken lobster pots, will clog the turbines.

A serious look at the science, Dadswell said, must include a determination of how much fish mortality are we willing to accept. He added that a lack of monitoring at Annapolis Royal means there is a lack of awareness about the issue.

Dr. Anna Redden of the Acadia Tidal Energy Institute said that in-stream, standalone turbines are garnering better approval ratings.




Did you know?

Dr. Mike J. Dadswell’s research and publications include the interaction of fishes and fisheries and human impact on the environment such as the Canso Causeway and the development of tidal power, the ocean migration patterns of Atlantic salmon, American shad and striped bass; the biology of Atlantic sturgeon, shortnose sturgeon and dogfish shark in Minas Basin and the Bay of Fundy.