Gaspereau begin comeback after $4M fish ladder installed
Logging and dams had driven gaspereau, a species of herring, from St. Margarets Bay watershed
A small but important fish is making a comeback to a Nova Scotia watershed for the first time in more than 100 years, thanks to a fish ladder.
Gaspereau — also known as the alewife — is a species of herring that is often used as bait in the lobster fishing industry.
The fish had once been common in Indian River, part of the St. Margaret's Bay watershed, before dams and the logging industry began using the river in the mid- to late-1800s.
According to a news release from Nova Scotia Power, a federal Department of Marine and Fisheries official noted the significant lack of fish when he toured the watershed on May 16, 1881.
Now, 135 years later, the gaspereau are back.
Last year, Nova Scotia Power, which generates 30 gigawatt hours of hydroelectricity per year from the water system, invested $4 million into building the largest fish ladder in the province. It is located at Sandy Lake Dam.
Longest fish ladder
It came about through a memorandum of understanding between the utility and the Department of Fisheries and Oceans to help re-establish the fish.
"We hope that it eventually it might even work for the return of some Atlantic salmon, but gaspereau are more prevalent still in Nova Scotia," said Terry Toner, director of environmental and Aboriginal affairs at Nova Scotia Power.
"The fish ladder is about 500 feet long. It's the longest one we've built in Nova Scotia."
Toner says the ladder is a pool and weir design. Fish work their way up through a series of buckets by jumping. There are resting pools "because it's a long journey for some of the fish." Once the fish reach the top of the ladder, they exit at Sandy Lake. They return to the sea in autumn.
On May 17, 135 years and one day after the federal inspector had been there, a field biologist with Nova Scotia Power checked the ladder and spotted three gaspereau in the resting pools.
"It's awesome, it's absolutely awesome," said Darcy Pettipas, the senior environmental technologist for NSP, in a news release.
For two weeks, Pettipas had been checking the ladder for signs of the fish. He'd seen speckled trout and smallmouth bass, but no gaspereau.
After the gaspereau were spotted, Pettipas went back with an underwater camera.
What he found was stunning.
"We saw many gaspereau throughout the ladder as well as speckled trout, smallmouth bass and a white sucker," Pettipas said.
The fish are an important food source for larger fish such as cod.
"Gaspereau tend to go back to spawn in the same river that they're used to. They imprint on the stream on their way out, and when they come back to spawn, most go up the river they were born in," Jay Walmsley, a senior environmental scientist, said in a news release.
Walmsley says gaspereau bring nutrients from the ocean.
"The more different types of fish we have in the system, the greater the diversity and productivity and the healthier the system," Walmsley said. "They are very beneficial to the ecosystem."
He said gaspereau using the ladder offers a promise that the fish will redistribute into the rest of the watershed.
With files from Anjuli Patil