Have you ever heard of hexactinellid sponges? I hadn’t either until I attended a BC Ferries 30 minute lecture about the creatures of our coastal waters. Hexactinellid sponges are one of the West Coast’s most astonishing hidden gems. And I mean hidden because they live deep within our coastal waters, out of sight from us land animals, and that is possibly why many don’t know about them.
Hexactinellid sponges, also referred to as glass sponges, have existed for millions of years, beyond the Jurassic period. What makes them unique today, is the BC coast is the only place in the world where they have formed reefs. These reef colonies span hundreds of square kilometers along the ocean floor, and they have been growing there for over 8,000 years. They were discovered during the late 1980s in the Queen Charlotte Basin, and more recently in 2005, in the Fraser Basin, close to the mouth of the river.
They are called glass sponges because of their fragility. Mostly white and yellow, they grow in a funnel or tubular shape. Each siliceous skeleton is inhabited by a sponge larvae that will grow, reach adulthood, and die, then new sponge larvae will inhabit the skeletons of past generations. The reefs they form are extremely important for providing habitat to hundreds of marine animals and sea life – crab, shrimp, prawn, sea urchins, rock fish, among others – it is important they remain intact. Due to the delicate make up of their external structures however, the sponges are extremely susceptible to damage.
Unfortunately, as the reefs have only been voluntarily protected in the past, lots of destruction has taken place due to fishing, especially by bottom trawling and dredging. Damage to the reefs could take up to 200 years to recover. While voluntary preventative measures have taken place in the past and a trawling ban was issued in northern reef colonies in 2006, the Queen Charlotte Basin and Fraser Basin Reefs are currently designated areas of interest as a Marine Protected Area.