New biodiversity discoveries are emerging from a novel collaboration involving drop-camera technology. Kelsey Dennison, a former Vancouver Aquarium volunteer, has been collaborating with Aquarium scientists Jeff Marliave and Donna Gibbs to reveal new findings about the biodiversity on glass sponge reefs (called bioherms) that occur throughout Howe Sound and elsewhere in British Columbia, but nowhere else on earth. Kelsey’s father, Glen Dennison, a founder of the Underwater Council of B.C., is a professional engineer who put the device together and provides vessel support for Kelsey’s survey transects.

The drop-camera method invented by the Dennisons is passive, and is virtually fail-safe in terms of potential damage to the reefs, in contrast to a costly ship cruise that uses a mini-sub on a cable (ROV), which could very likely cause significant mechanical damage to the delicate sponges.

During a calm period with flat sea surface, the Dennisons unreel their drop-camera over the Lions Bay pinnacle reefs, and it drift with the currents over the top of the reef. The wide-angle lens of the camera enables Kelsey to manually pull the camera up before any contact can occur with the sponges. This very slow-speed approach also yields video footage that can be closely examined for identification of marine life that might escape notice in videos from rapid mini-sub tracks, as you will see from this video:


The researchers have varying interpretations of the video footage taken of the reef – one had reported “lots of cannonballs” on this reef, but another countered that some of the balls were casting shadows below them. A lead cannonball would sink into the relatively soft clay-stabilized glass sponge tissue that forms the base for a sponge reef. Careful scrutiny of the footage enabled Aquarium scientists to confirm the identity of sponge balls (see video below).


Along with the high abundance of squat lobsters, rockfish were identified from drop-camera footage, plus the armoured ball sponge (Geodia mesotriaena), a type of sponge that is not related to the glass sponges that form the reef. These ball sponges attach to dead cloud sponge tissue on the reef. They were previously known only attached to rocks. Very few species other than the rockfishes, squat lobsters and ball sponges were seen, but fish like the lingcod and a flatfish, plus a few crabs and shrimps, were identified.

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One Response

  1. Sheila Byers

    Awesome footage in these videos! The glass sponges are impressive but who would have noticed the ball sponges. Can see the squat lobsters and there are probably more smaller invertes there but not readily visible. Great work and documentation of these bioherms by Kelsey and Glen.


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