Despite the importance of the blue crab fishery to Florida’s coastal communities, derelict blue crab traps are a growing problem. In recent years, however, awareness of the impact derelict traps have on marine life, the environment and public safety has increased.
In May 2011, Charlotte County Sea Grant Extension Agent Betty Staugler began a project to demonstrate the utility of using side scan sonar to mitigate the impacts of derelict crab traps in coastal waters. Side scan sonar is a specialized system for detecting objects on the sea floor.
Staugler received a side scan sonar unit on loan from Virginia Institute of Marine Sciences (VIMS) in order to see if this technology could be used to identify submerged abandoned blue crab traps within the dark waters of the Peace River. VIMS researchers have successfully used side scan to identify submerged traps in Chesapeake Bay for the last four years.
In 2008, the Blue Crab Advisory Board made up of industry stakeholders from around the state, discussed ways to remove derelict traps and proposed regional closures to help identify derelict traps. A number of workshops were held, with comments relayed back to the board. The board then selected six regions and closure dates to minimize the economic impact of the closures to the industry.
The 10-day regional blue crab trap closures, which began in July 2009, were implemented because Florida law is specific as to what is considered a derelict trap during the open season, making it difficult to identify traps that become lost or abandoned. Two trap retrieval approaches are being used to remove traps during the closures: community based cleanups and contracted trap retrieval.
Through field testing of the side scan, Staugler was able to identify more than 100 submerged traps prior to the 2011 rotational closure for southwest Florida. Using the side scan with targets identified and a homemade dragline, Staugler and a crew of volunteers were able to recover 61 submerged traps during the closure.
Thirty three percent (20 traps) of the submerged traps were still fishing when recovered. Seventy five blue crabs trapped inside were released as well as a handful of other fish and invertebrate species. Traps were recovered in water depths ranging from 3 to 16 feet. This project demonstrates the utility of using side scan to mitigate the impacts of derelict fishing gear in coastal waters.
- Florida Fish and Wildlife Conservation Commission Regulations for Blue Crabs
- Derelict Blue Crab Trap Removal Manual for Florida