Trawler damages part of NEPTUNE Canada network

A small portion of the NEPTUNE Canada ocean network suffered a setback earlier this year when some of the instruments at the Barkley Canyon site were accidentally snagged by a trawler. “Despite best efforts to avoid it, this kind of incident is unfortunate but a calculated risk of conducting research on this ocean frontier,” says Dr. Martin Taylor, president of Ocean Networks Canada, the network’s managing organization.

NEPTUNE Canada—which is part of UVic’s ONC Observatory—is the world’s first regional ocean network and collects critical information on ocean processes 24/7. The network has 15 study areas among its five nodes on an 800-km loop of cable stretching from the west coast of Vancouver Island to deep-sea hot vents 300 km offshore.

The Barkley Canyon node lies at 600-metre water depth, near the top of the continental slope. A cable connects it to two instrumented platforms at a special study site on the canyon’s upper slope 10 km away.

The upwelling of nutrients driving the region’s rich biodiversity makes the upper slope a crucial study area for scientific, economic, environmental and public policy purposes. It also makes it a popular region for commercial fishing.

Sensors were working normally at the Barkley Canyon instruments on Feb. 18 when they detected something approaching from above. Moments later, instruments for measuring earthquakes, tsunamis and ocean currents, as well as a camera and an underwater hydrophone, went offline. The precise time and direction of trawling is known from this data.

“Placing a study site on the upper slope is not a risk-free venture, but it’s a vital one for monitoring the health of the ocean and even providing valuable information to fishers,” says Taylor.

Ninety per cent of the NEPTUNE Canada network—including instruments elsewhere at the Barkley site—is unaffected by the hit and continues to stream data.

During planning and installation, the ONC team took all steps to minimize the risk of a trawler hit: cable was buried rather than letting it lie exposed on the seafloor and power nodes were secured in heavy trawl-resistant frames. Onshore, ONC regularly connects with the fishing community, provides location data for fishers’ navigational systems, and posts notices to mariners advising ships to keep at least 2 km away.

Fortunately, only the Barkley area instruments are vulnerable to trawling. Other study areas are too deep or in trawl-free zones near shore.

Fishing boats usually have observers on board and must supply ship logs describing their activities and routes to the Department of Fisheries and Oceans.

ONC was insured against such accidents, but there is a significant deductible cost.

The team will recover the affected equipment on its July expedition to service the NEPTUNE Canada network. Only then can the damage be assessed, and next steps determined.

“We hope the damage can be repaired quickly so we can get the instruments back online and continue the vital research in the Barkley area,” says Taylor.