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Title:	Effectiveness of a sea turtle-deflecting hopper dredge draghead in Port Canaveral Entrance Channel, Florida
Authors:	Nelson, David A. (David Arthur), 1955- Shafer, Deborah J.
Keywords:	Loggerhead turtles Caretta caretta Sea turtles Rigid deflector draghead Dredging Environmental effects
Publisher:	Environmental Laboratory (U.S.)
Series/Report no.:	Miscellaneous Paper;D-96-3
Abstract:	Abstract: The rigid deflector draghead was tested on a hopper dredge in Port Canaveral Harbor entrance channel from 16-30 September 1994. The effectiveness of the draghead was assessed by determining if turtles were: (a.) present in the channel in sufficient numbers to encounter the draghead, (b.) on the channel bottom where they were most susceptible to entrainment by the draghead, and (c.) entrained by the rigid deflector draghead at a lower rate than by the California draghead. A total of 13 turtles (0.47 turtle/hour) were captured during three standardized sea turtle trawl surveys. The activities of 12 loggerhead turtles (Caretta caretta) were monitored intermittently from 5-30 September 1994 using radio tags and depth-sensitive sonic tags. These behavioral studies showed that loggerhead turtles spent most of their time (83.2 percent) on the seafloor. No loggerhead turtles were entrained during the dredging operations; however, one small green turtle (Chelonia mydas) was entrained during the dredging (0.09 turtle/day). Based on the observed levels of sea turtle abundance, a preponderance of bottom time for loggerhead sea turtles, and a low rate of sea turtle entrainment, the rigid deflector draghead may be effective in reducing sea turtle entrainment by hopper dredge in Port Canaveral Harbor entrance channel.
URI:	http://hdl.handle.net/11681/20464
Appears in Collections:	Miscellaneous Paper