A New Eye on Deep-Sea Fisheries

Imagine that officials charged with setting deer-hunting limits had to assess the herd’s abundance by flying over forests at night. That’s a little like what the National Marine Fisheries Services (NMFS) is up against to set fishing quotas for deep-sea scallops.

To get new views into the deep, Woods Hole Oceanographic Institution (WHOI) scientists built HabCam, a stereo-optic camera and lighting system mounted on a metal frame. It is towed by a ship 6 to 8 feet above the seafloor, snapping six images per second. Covering 100 nautical miles per day, it creates vivid ribbonlike photomosaics showing where, what, and how much life lies on the seafloor.

Unlike dredge sampling, HabCam doesn’t disturb seafloor ecosystems. The 3-D images provide millimeter-scale resolution of seafloor contours, said WHOI biologist Scott Gallager. “In addition to information on scallops, HabCam also provides a huge amount of data on seafloor habitat. We are seeing that the more complex or three-dimensional the seafloor habitat is, the higher the diversity of organisms and communities it can support.”

HabCam is also equipped with sensors that measure temperature, salinity, chlorophyll levels, and other ocean conditions. It has a side-scan sonar that images seafloor contours 50 meters on either side of the vehicle, about the size of a football field. These data, combined with the images, reveal a much fuller picture of all the factors that create ecosystems.

“Now we can add the fourth dimension—time—to see how seafloor ecosystems change, especially as climate change causes ocean temperatures to rise and pH to drop,” Gallager said. “Using repeated surveys, we can see if communities are changing, and we can use environmental conditions to predict whether they will survive in particular locations.”

HabCam was developed in partnership with commercial fishermen and NMFS scientists, Gallager said. “The intent is to provide the commercial fishing industry with the capability to see the ocean floor and the distribution and abundance of organisms on it. This will help improve management of fish and shellfish populations by empowering the industry with knowledge we haven’t been able to provide before.” 

This research was funded by the National Oceanic and Atmospheric Administration and the Research Set Aside Program, which supports basic research through a percentage of dockside sales of scallops.