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Canada Expands Protections for Rare Reefs Made of Glass

March 8, 2019, 11:00 AM

Canada has extended protections for a rare ocean reef made of sea sponges once thought to have disappeared with the dinosaurs.

Glass sponge reefs—named that way because they’re comprised of silica—are for the most part only found on Canada’s Pacific coast, Sabine Jessen, a conservationist who works to protect the reefs, told Bloomberg Environment.

Fisheries and Oceans Minister Jonathan Wilkinson announced March 6 that a new 3.5 square kilometer area will be closed to fishing to protect the reefs, which shatter easily if touched by a trap or other fishing gear being lowered to the sea floor.

“It’s been a long hard slog, but we’re getting there,” said Jessen, national director of the Canadian Parks and Wilderness Society’s oceans program.

Raising a Glass to Protections

Fisheries and Oceans Canada protected nine glass sponge reefs in 2016 and selected nine more for this latest round of protections, Wilkinson told Bloomberg Environment in a March 6 interview.

“This is an expansion of protections for what are pretty unique biological organisms,” Wilkinson said.

Canadian authorities discovered the first living glass sponge reefs in British Columbia’s Hecate Strait in the late 1990s while mapping the sea floor, Jessen said.

A glass reef created a system of famed cliffs in the Danube River valley in Germany around 200 million years ago, but experts thought the creatures had gone extinct.

The reefs in British Columbia can be eight stories high and as long as 20 kilometers, Jessen said. Some have also been dated to be 9,000 years old, she added.

The sponges feel like a meringue or prawn crackers when held, she said.

Unique Creatures

Individual glass sponges exist elsewhere in the world but the only known reefs are in Canada, with the exception of a few nearby on the southern tip of the Alaskan panhandle, Dr. Sally Leys, a biologist with the University of Alberta, told Bloomberg Environment in an interview March 7.

Experts believe that’s because of the combination of silica from rivers originating in the Rockies, cold water, and abundant sea life, Leys said.

The sponges perform critical roles in the ecosystem, namely by filtering out bacteria from the seawater and releasing nitrogen-rich ammonia, which then feeds phytoplankton. The reefs also create shelter for 84 other animals, including prawn, crabs, and rockfish, according to the Canadian Parks and Wilderness Society.

The reefs are formed when the sponges die, leave behind their silica-based skeleton, and then grow upward on top of the skeleton. The sponges have other unique properties, including using electrical signals to control the water that flows through them, Leys said. Most sponges don’t have a nervous system.

Fiber Optic Application

The glass sponge reefs could also one day change the way fiber optics are made, she said.

Making fiber optics requires a lot of heat, but the sponges create their skeletons at very low temperatures, spurring interest from researchers who are trying to understand how they grow.

The reefs also have value in and of themselves for divers and tourists lucky enough to see them, Leys said.

“You get the same feeling when you walk through old growth rainforest,” she said. “You’re in awe of nature.”

The newly-protected reefs are all in Howe Sound, a busy inlet north of Vancouver.

‘Marine Refuges’

The reefs are classified as marine refuges rather than more strictly protected marine protected areas. Any commercial, recreational, and indigenous fishing that involves touching the sea floor is prohibited in the refuges, but fishing on the surface is permitted.

Fishing vessels also can’t fish within a 150-meter buffer zone around the reefs because sediment can easily damage the sponges, and boats anchoring in the refuges could hurt the reefs, according to Jessen, from the Parks and Wilderness Society.

A prawn fishery has operated in Howe Sound since 1914 and today that area provides fresh produce for stores and restaurants in Vancouver, Mike Atkins, executive director of the Pacific Prawn Fishermen’s Association, said March 7.

The fishery had hoped that long history and the fact the reefs are healthy would have meant the sector had been seen as low-impact in the eyes of Fisheries and Oceans Canada, Atkins said.

Push for Narrower Buffer Rebuffed

A push by some fishermen to reduce the buffer to 50 meters wasn’t endorsed by the association, he added.

Howe Sound is a productive area for the provincial prawn industry—which is valued at C$40 million ($29.7 million)—so the fishing industry near the marine refuges will take an economic hit, Atkins said.

“They’re likely won’t be the space for that many fishermen, some will have to move elsewhere,” he said, but added that the industry didn’t want to be involved in damaging the reefs, he added.

To contact the reporter on this story: James Munson in Toronto at

To contact the editors responsible for this story: Gregory Henderson at; Steven Gibb at; Anna Yukhananov at