By Mark Cardwell
The decade-old effort aimed at building a massive kelp forest to help sea life flourish in the harbour of Sept-Îles is beginning to bear fruit. Created to enhance the marine habitat in the natural 45-square-km body of water, the plan began in 2007 with the construction of several dozen concrete structures on the harbour’s sandy seabed. Since then, more than 200 structures have been installed, including 160 in 2014.
According to the port’s engineer, Manon d’Auteuil, the recent results of an ongoing harbour monitoring program by a local environmental research agency institute suggest the structures that have been in the water for two to four years are swimming in kelp.
“We’ve found that 100 percent of the surfaces are covered within two to four years of installation,” said d’Auteuil. “So we’re both happy and confident that we’ve managed to create a new and viable ecosystem in our harbour.”
That was the goal, she noted, when the plan was first elaborated as an offshoot of Port of Sept-Îles’ multi-user wharf construction project, which was completed in January of this year. Kelp – large habitat-enhancing seaweed that belongs to the brown algae family, and that grows in dense underwater forests in shallow ocean waters – were targeted from the get go as the key to the project’s success.
In addition to providing both nutrients and protective shelter for all manner of marine life, kelps are also known for their rapid growth. Some of the 30 known species of brown algae can grow half a metre in a single day, and reach lengths of 75 metres or more.
D’Auteuil said concrete platforms provide the perfect surfaces for kelp to grow on. “Algae need something to anchor on,” she told Canadian Sailings. “And concrete is perfect because it is roughly edged and stands up well against the elements of the sea.”
She described the shape of the manmade structures installed on the harbour’s seabed as “pyramids without tops.” They are also lined with holes that allow smaller fish and other sea creatures to swim through in search of food, and to avoid predators.
She said the holes were widened last year to 8 inches after Fisheries and Oceans Canada suggested the 4-inch holes that were initially being used were too small for most fish to swim through, and were being plugged by fast-growing algae. D’Auteuil said various above- and below-water tests are now being carried out by the Institut nordique de recherche en environnement et en santé au travail – or INREST – a research unit of the Cégep de Sept-Îles.
Under an agreement signed between the port and INREST last August, scientists and students take and study samples of water, sediment, and sea life from around the bay from May to December. Divers also photograph and take samples of kelp growing on and around the concrete structures, and conduct census studies on marine life – everything from fish and crabs to lobsters and starfish.
“The goal is to build and maintain an environmental portrait of the bay so that we understand what’s there and then see any impacts that our operations might have so that we can take measures to help improve our procedures,” said D’Auteuil. She added that the results of the first round of samples, which were taken last summer and fall, suggest that life is now teeming in the once barren waters in the harbour of Sept-Îles.
“So far so good,” said D’Auteuil. “But the sample numbers are still pretty small. We’ll have a better picture when (INREST) tables its first full report this fall.”