Symposium Abstract: Effects of Smooth Bottom Trawl Gear on Soft Bottom Habitat
C. L. Cogswell, B. Hecker, A. Michael, F. Mirarchi, J. Ryther, Jr., D. Stevenson, R. Valente, and C. Wright
In January 2001, Boat Kathleen A. Mirarchi, Inc. and CR Environmental, Inc. were awarded a NOAA Cooperative Research Project to study smooth bottom fishing gear-induced habitat impacts to soft bottom habitats in Massachusetts Bay off Scituate, MA. To date, most of the research on effects of otter trawling on the seafloor has focused on long-term cumulative changes to gravel bottom or rocky substrate and few studies have looked at trawl effects on soft bottom habitat types. Using local fishermen’s knowledge, two ‘soft’ bottom fishing areas, a lightly trawled area (Little Tow) and a more heavily trawled area (Mud Hole) were selected for the study. Replicate reference and experimental trawl corridors were established in 120 to 140 ft of water. For the july 2001 ‘immediate impact study’ the bottom and water column were characterized before and after repetitive passes with a smooth bottom otter trawl. Areas were surveyed for benthic organisms, sediment surface characteristics, water column parameters, epifauna and infauna, and fish and fish prey. An expansion of the project was funded by NOAA for 2002 to investigate ‘chronic trawling impacts’ by continuing to trawl the experimental trawl corridors twice a week from early August into November. Surveys along reference and experimental trawl lanes measured parameters similar to those investigated in 2001 and were conducted in July 2002 (pre-chronic trawling), in September 2002, and again in November 2002 to study the cumulative effects of chronic trawling. Cooperative Research funded by NOAA/NMFS.