Human-made structures placed in the ocean don’t tend to stay clean for long. Blank surfaces are a beacon for seaweeds and animals like barnacles and sponges looking for a nice place to settle, which means a buoy and its underwater oceanography sensors bobbing off the Central Coast of British Columbia are prime real estate. Time to call in the underwater maintenance crew.
In the late summer and into the fall, a team of divers from the Hakai Institute and the Central Coast Indigenous Resource Alliance (CCIRA) were stationed at the Hakai Institute’s ecological observatory on Calvert Island for six weeks of rockfish surveys. When they weren’t counting fish, the team completed other important underwater tasks.
On a brisk morning in late September, the dive team headed out 11 kilometers east of the observatory to do some maintenance on the KC Buoy at the mouth of Kwakshua Channel. Although it got a tune-up this past winter, some of the sensors needed to be inspected, others replaced, and a bit of a scrub down is always appreciated. But once they dropped below the surface, the divers realized this mission might be tougher than they initially thought.
“There were so many mussels that they built a curtain spreading across one [buoy] support to the next, affixing themselves to only their neighboring mussels,” says veteran diver Derek Van Maanen. “Not one instrument or sensor was visible.”
Tens of thousands of mussels in layers up to 30 centimeters deep—roughly equivalent to four or five bricks stacked on top of each other—had attached themselves to the equipment. This is more broadly known as biofouling, where a build-up of organisms affects the structure and function of underwater equipment.
