This code stake at Defence Island sponge reef helps scientists keep track of changes over time.
Sponge reefs serve an important ecological function as habitat, breeding and nursery areas for fish and invertebrates. To date, the only accessible glass sponge reefs for scuba divers are in found in Howe Sound. Of the dozens of glass sponge reefs in Howe Sound, only five sites have reefs shallow enough to be reached by divers, and only three of those sites are relatively safe in terms of depth profile. A generous donation from Mountain Equipment Coop, is funding additional tools and resources for this continuing research at the Vancouver Aquarium Marine Science Centre including a new webpage for sport divers to document growth in cloud sponges that form these reefs in Howe Sound.
Now, divers across B.C. can help collect valuable data on sponge gardens, which differ from reefs in that the sponges are growing directly on rock rather than on skeletons of previous sponges that are geologically stabilized by silt. In a garden the array of different sponges is easier to visualize through time, so that individuals can be identified.
The photos below show one sponge garden, photographed in October 2012 and November 2014. Over that two year period, significant growth can be detected based on video frames. In the 2012 photo, two small orange sponges are growing just inside the two larger white sponges at the bottom of the frame.
In the 2014 photo, the orange sponge on the right side is now contiguous (slightly behind) the much larger white sponge on the right, and it is difficult to spot the orange sponge next to the big white sponge on the left, because it is being overgrown by the white sponge. It appears that the orange sponges have not grown as fast as the white ones at this site over these two years. Very little is known about these glass sponges, and the growth evident in these two photos demonstrates faster growth than ever documented in scientific literature.
If you’re a diver in the Vancouver area, you can contribute valuable scientific documentation by submitting videos and photos of cloud sponges in Howe Sound. Visit our new Mountain Equipment Coop funded sponge reef webpage launched last week to learn more.