Ground-truthing Glass Sponge Reefs from the CCGS Vector

On May 27, 2019 an early morning ride on BC Ferries from Horseshoe Bay to Langdale quickly found me on the Sunshine Coast heading for nearby Hopkins Landing. A Coast Guard zodiac with the Chief Research Scientist from DFO Habitat Ecology Program, Dr Anya Dunham, was at the dock waiting for several of us to arrive. Dr Kim Conway of Natural Resources Canada, Deirdre Finn, the DFO Fisheries Management Officer, and Gavin Joe of the Sechelt Nation all jumped aboard for the ride towards Carmelo Point on Gambier Island where the CCGS Vector was already at work. The CCGS Vector is a hydrographic survey vessel of the Canadian Coast Guard and loaded on the aft deck was the remotely operated vehicle (ROV) called the Phantom H2 operated by DFO Science team.

The DFO Habitat Ecology team of scientists had been on the Vector in Howe Sound for several days ground-truthing new locations mapped as possible glass sponge reefs. The majority of known glass sponge reefs exist on the east side of Howe Sound, situated in a mostly north/south orientation from the Squamish estuary. Nine of these reefs that were discovered by MLSS Director Glen Dennison and his assistants, were recently protected within eight marine refuges on March 6, 2019. Yet, several mapped locations on the east side and west side of the Sound remained unconfirmed. Some of these were first described by Glen and others were found by NRCan scientists Kim Conway and Rob Kung who analyzed multibeam and backscatter sonar data layers looking for signs of geological reef presence. The task for scientists on the CCGS Vector was to investigate these reef structures.

Using the Phantom ROV, DFO confirmed the presence of some large, beautiful live reef areas near Langdale and in Collingwood Channel on the west side of Howe Sound. Several locations on the east side appeared to have been alive in the past but are no longer supporting living reefs. Another location off Bowen Island near September Morn was too close to shore for the Vector and Phantom to safely access. As part of the ‘new arrivals’ on the zodiac, we were onboard to observe the Phantom H2 ROV diving and documenting transects along several reefs previously discovered by Kim Conway and Rob Kung, NRCan while analyzing the geological signature off Carmelo Point.

Phantom ROV 2019 (DFO image and credit)

In the interim when the Phantom was being deployed over the side of the Vector, we had a chance to review the video of the reef transacts off Langdale – and were the sponges spectacular! Tall and beautiful!! Do people traveling on the BC Ferry from Horseshoe to Langdale know what incredibly diverse habitats lie beneath them?

As the Phantom was maneuvered above the seabed off Carmelo Point, it was exciting to watch the glass sponge come into view. Although the sponges on these reefs were in clumps and clusters, not as dense as those near Langdale, small juvenile Yelloweyes, squat lobsters and spot prawns were observed, highlighting the important habitat that these reefs provide for many rockfish and invertebrate species. Also not uncommon, was human trash and remnants of fishing gear.

Our day culminated with the deployment of geological equipment to retrieve sediment samples. A weighted steel tube lined with a plastic core tube was lowered into the middle dead sections of the Carmelo Point reefs and similarly in the Collingwood Channel reefs. The purpose of the cores was to determine an estimate of how long ago the sponge in these dead reef sections had been alive (in terms of decades or, <100 years) by tracing lead and carbon isotopes within the sponge spicule-laden sediments. A total of six cores were retrieved for analyses. I can’t wait to get the results of these sediment cores!

Howe Sound, with its temperamental weather and currents, provided us with an excellent day of field work on the CCGS Vector with happy, dedicated scientists and Coast Guard crew members working hard to obtain the necessary evidence to support the protection of sensitive benthic habitats like glass sponge reefs. Thank you to DFO for accommodating additional ENGO participants on the Vector.

CCGS Vector Phantom ROV 2019 team (DFO image and credit)

Corer sampler (ScB)

Langdale sponge image (DFO image and credit)
CCGS Vector (DFO image and credit)



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