Evaluating Techniques to Reduce Crab Trap Float Loss in South Carolina

SCNDR Field Biologist Watches a Float.
A SCDNR field biologist watches a float as it's run over.

The South Carolina Department of Natural Resources is evaluating crab trap float rigging designs that may reduce crab trap damage and loss from boat strikes.

Project Dates: March 2014 - February 2015

What’s the project?
The South Carolina Department of Natural Resources (SCDNR) is testing the effectiveness of different float configurations for reducing or preventing derelict crab traps, removing and recycling derelict traps, and surveying the rate of trap loss in the area. SCDNR is conducting the study in the Stono River near Charleston, SC, an area where commercial crabbers have reported high crab trap float losses due to boat strikes from vessel traffic.

Researchers are comparing a single float and line rigging – a standard among crabbers – to different float/line configurations. For example, one treatment group replaces the standard buoy with a more durable one. Another treatment group includes PVC piping to protect the line. A third treatment group combines a more durable buoy with PVC. Additionally, the team is surveying all active crab trap license holders to better characterize the frequency of derelict crab trap generation in South Carolina waters.

Boat strikes can destroy floats and cut crab trap lines, which often prevents fishermen from recovering their traps. Derelict or abandoned crab traps are a threat to wildlife, can degrade habitat, and become a navigation hazard. These traps may “ghost fish” for years, capturing and killing crabs, diamondback terrapins, and various fish species. Though many groups have worked to reduce the number of derelict crab traps through removal efforts, this project aims to prevent them from becoming derelict in the first place.

Who is involved?
This project is part of a Fishing for Energy gear innovation grant, administered by the National Fish and Wildlife Foundation (NFWF) and funded by the NOAA Marine Debris Program.

What does it accomplish?
This project tests the durability of crab trap float riggings. From these findings, the SCDNR will produce recommendations for recreation and commercial crabbers on float configurations that reduce crab trap loss. Moreover, results from the survey will help characterize the annual crab trap loss rates in South Carolina.

What is something unique about the project?
Crab traps recovered in this study, and those donated by commercial crabbers engaged in the project, will be used to create oyster reef habitat. The crab traps will be cement-coated, which provides settlement substrate for oysters and has been shown promote development of new reefs that act as essential fish habitat for fauna diversity.