Research supports targeted trawling

Professor's study finds minimal impacts on some seafloor habitat

Trawling, a fishing method that involves dragging large nets across the seafloor, has been criticized by environmental advocates for its demonstrated damage to rocky marine habitats and the long-lived animals that occur in them. However, important questions remain about the extent of any damage to sandy and muddy environments.

Research by Dr. James Lindholm, James W. Rote distinguished professor of marine science and policy at CSU Monterey Bay, colleagues from The Nature Conservancy and commercial fishermen indicates that the damage may be negligible.

During the three-year study, fishermen trawled patches of the ocean floor off Morro Bay. Those areas were analyzed by underwater photos and video and compared with nearby areas that were untouched.

Their peer-reviewed work, published in the Fishery Bulletin, found that California’s largely soft-bottom seafloor saw little lasting impacts from trawling with a small-footrope trawl.

Petrale sole

Petrale sole, a flatfish caught by trawling on soft-bottom seafloor. Photo courtesy of The Nature Conservancy

In a blog post, the researchers say their study adds to a growing body of literature from around the world showing trawling impacts are context-dependent: the impacts depend on the type of gear used, the types of habitats trawled and how often trawling occurs.

The scientists point out that their study does not imply that all soft-bottom habitats should be open to trawling; but, with new research and technology, “we can fine-tune our fishery regulations to protect truly vulnerable habitats.”

Dr. Lindholm has been studying marine ecosystems for 20 years.This fall, he will conduct a similar experiment off Half Moon Bay using trawling nets of different sizes. Commercial fishermen will also be involved.