Watching hake and rockfish swimming hard as they slip down the narrowing throat of a midwater trawl, it’s clear the net catches everything. But not everything belongs in the net. Alaska salmon, certain Pacific rockfish, and Atlantic cod are among the species midwater trawler captains work to avoid.
Under the banner of conservation engineering, fishermen, regulators, marine electronics manufacturers, and net makers are working on a number of innovations — new bycatch excluder designs, LED lights, and cameras — that are helping midwater trawlers reduce bycatch.
“Bycatch is the number one reason fishermen buy the system,” says Jason Whittle, vice president at Ocean Systems. Ocean Systems’ SeaTrex, according to Whittle, is a simple but robust color camera that runs on a third wire and uses 1,500-lumen white lights and a wide-angle lens to help fishermen see what’s going into their nets.
“With rockfish, you have to see the colors to know which ones you’re getting, and that requires white light,” Whittle says, noting that his company’s focus is on imagery. (Whittle offers up a YouTube video of fish going into a net to lure curious fishermen: tinyurl.com/seatrex.)
Whittle points out that all camera controls are preset when the device goes overboard in the net. That means all the capacity of the third wire is used for transmission from the camera.
“Our cameras are very simple,” he says. “The less information you have going up and down that wire, the better the quality of the image.”
Keeping it simple makes the cameras affordable and easier to service, Whittle points out. “Our system is under $50,000,” he says. “And in the two years we’ve been selling them, we haven’t really had any service issues.”
Other marine electronics companies — including Simrad, Wesmar, and the newcomer SmartCatch — are using cameras to monitor bycatch as well as performance of escapement designs that use fish behavior to help salmon and other species get out of the net before it is hauled.
Rob Terry, co-founder and CTO at SmartCatch, also touts the price points of the $40,000 SmartCatch system. In response to the needs to the fishermen he works with, SmartCatch has a moveable camera with adjustable lights.
“We’re designing the next version so you don’t have to take it off when the net goes onto the reel,” says Terry. The F/V Constellation in Alaska, and the Excalibur out of Newport, Ore., are among the vessels using the SmartCatch system, and Terry reports good results.