Accession Number : AD1053406

Title :   Use of an Acoustic Camera to Evaluate the Performance of Tickler Chains and Draghead Deflectors for Sea Turtle Protection during Hopper Dredging in the United States of America

Descriptive Note : Technical Report


Personal Author(s) : Dickerson,Dena ; Welp,Timothy ; Willis,Stephen ; Novy,Douglas

Full Text :

Report Date : 01 May 2018

Pagination or Media Count : 41

Abstract : Potential risk for incidental take of sea turtles exists during hopper dredging throughout sea turtle coastal habitats. While the international dredging community has incorporated turtle protection methods developed by the U.S. Army Corps of Engineers, alternative protection measures have also been tried. One such method is a curtain of chains hanging off the dragarm pipe ahead of the draghead, which is intended to disturb a turtle on or near the seafloor and avoid a turtle take by the draghead. Although these turtle tickler chains (TTC) have been used overseas, neither operational performance nor effectiveness in protecting sea turtles has been documented.This study was the first step in evaluating TTC as a potential replacement for draghead turtle deflectors. The primary objective was to evaluate and document operational performance of this technology, not effectiveness of reducing incidental take. TTC operational performance was monitored using underwater camera systems over a short period of time whereas effectiveness for reducing incidental take of sea turtles would require analysis of endangered species observer monitoring data collected over a longer period. This study successfully demonstrated operational feasibility of deploying TTC off the dragarm and feasibility for mounting acoustic cameras on the dragarm for underwater monitoring.

Descriptors :   dredging , Environmental protection , TURTLES , acoustics , cameras , CHAINS , DEFLECTORS , monitoring , test and evaluation , ARMY CORPS OF ENGINEERS , seabed

Subject Categories : Civil Engineering
      Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE