July 11, 2012 — Atlantic sea scallops are one of the most valuable fisheries in the United States, with a current ex-vessel value of approximately $450 million. Since they’re so valuable, we need to estimate and count scallops as precisely as possible.
Traditionally, scientists surveyed with dredges that drag along the ocean floor, damaging important habitat along the way. In 2005, they started using an alternative tool called the Habitat Camera Mapping System—also called HabCam—and it has revolutionized the way we survey scallops.
“It’s a digital underwater camera survey that doesn’t harm habitat and gives more precise scallop estimates, which in the end, may keep more money in fishermen’s pockets,” NOAA fishery biologist Laura Oremland said. “This new technology helps maximize the fishing while sustaining the fishery and preserving the ocean floor.” The HabCam concept was designed together by fisherman and scientists and has been funded by NOAA Fisheries, the Scallop Research Set-Aside Program, the Northeast Consortium, and NOAA’s Integrated Ocean Observing Systems Program at different stages in its development.
What’s the key difference between the survey methods? Accuracy and sampling power. The dredge can take only one or two dozen samples in a day, whereas HabCam can take the equivalent of a few hundred thousand samples. The more observations, the more accurate the scallop abundance estimate can be.
The camera system is towed by boat and submersed in water two to three meters above the bottom of the seafloor, typically at about 5.8 mile per hour. Rapid photo streams are sent to the ship over a fiber-optic cable, where they are recorded on hard drives. This stream of images can later be stitched together to form a mosaic of the seafloor.
Four strobes are synched to flash with the camera. The sensors, strobes, and camera sit in a steel cage for protection against impact with the ship during setting and haul back of the instrument. Technicians on the ship see images and data while flying HabCam. Scallop measurements from the images are translated into a true size and biomass measurement. In addition, new software allows automated counting and measurement on the ship while the instrument is being towed.
One huge hallmark of HabCam is that it’s currently working in the field. NOAA Fisheries sea scallop survey used HabCam in 2009 as well as 2011. For the 2012 scallop estimates, HabCam will be the primary survey tool for biomass estimates. Next up? The newest HabCam model captures 3D imagery of the seafloor and will be used for the first time on sea scallop surveys this year.
Read the full story on the NOAA website
Related Links: Read abou the 2011 SMAST scallop survey on Saving Seafood