Scads of sponge: Glass sponge reefs designated Marine Protected Area in Hecate Strait

The glass sponge reefs in Hecate Strait extend for hundreds of kilometres, and in some areas are 60 feet high.
Photo courtesy of Dr. S. Leys and the Department of Fisheries and Oceans

— By Molly Clarkson

In 1987 an incredible underwater discovery took place in Hecate Strait: glass sponge reefs, thought to be extinct for over 100 million years, were found to be alive and well along the northern Pacific continental shelf.

The reefs date back more than 9,000 years – just after the end of the last ice age – and cover an area of approximately 2410 km². Since the discovery in 1987, more reefs have been discovered in the Strait of Georgia and off the west coast of Washington state. However, the Hecate Strait/Queen Charlotte Sound reefs are by far the largest.

The skeletons of these sponges consist of needle-like silica (a mineral used in making glass) fused together to form delicate structures that are covered in a gel-like substance called cytoplasm. The sponges filter huge volumes of nutrient-rich ocean water through this ’skin’ and porous skeletal structure, in the process cleaning the water and sequestering carbon in their bodies. The reefs also create habitat for juvenile and pregnant rockfish, and crustaceans such as crabs, prawns and shrimp.

Not surprisingly, the reefs are extremely fragile. Bottom trawling and other commercial fishing activities have already destroyed or damaged a portion of the Hecate Strait reefs, and voluntary avoidance agreements have not put a stop to this problem.

To protect these sites from further damage, in June 2010 Canada declared the four reefs in Hecate Strait and nearby Queen Charlotte Sound an “Area of Interest” for increased protection. Five years later, the Department of Fisheries and Oceans moved to declare them as Canada’s ninth marine protected area (MPA). Proposed regulations for the MPA consist of a core protection zone where no human activity whatsoever will be permitted, along with a buffer area where activities that pose fewer risks to the reef (e.g. hook-and-line fishing operations and surface traffic) will be permitted.

Protection of these reefs is part of a process along the Pacific North Coast to establish an ecologically representative network of marine protected areas (MPAs). The Haida nation is in the process of engaging in this process, and, in partnership with the provincial government will identify protected areas designated under the Haida Gwaii Marine Plan to be brought forward as MPA candidates.

DID YOU KNOW?

Although there are over 500 species of glass sponge thriving in the oceans today, reef-forming species of sponge were thought to have gone extinct when plesiosaurs (below) still roamed the world’s seas. It was believed that the sponge died out because of competition from diatoms – single-celled algae that use the silica in seawater to build cell walls – the same substance sponge’s use to build their skeletons.