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2012 Turtle Excluder Device testing and gear evaluations
  • Published Date:
    2015
Filetype[PDF - 1.70 MB]


Details:
  • Corporate Authors:
    Southeast Fisheries Science Center (U.S.), Mississippi Laboratories,
  • Series:
    NOAA technical memorandum NMFS-SEFSC ; 674
  • Document Type:
  • Description:
    The NOAA National Marine Fisheries Service (NMFS), Southeast Fisheries Science Center (SEFSC), Mississippi Laboratory, Harvesting Systems & Engineering Branch conducted fishing gear evaluations in Panama City, Florida from June 5 through June 20, 2012. Four separate projects were conducted: 1) evaluation of Turtle Excluder Devices (TEDs) in skimmer trawls; 2) evaluation of Cable TEDs in fish trawls; 3) sea turtle exclusion rate trials for TED component variations; 4) evaluation of Bycatch Reduction Devices (BRDs) in shrimp trawls. Skimmer trawl TED evaluations were conducted aboard two contracted commercial vessels. Divers evaluated three different size TEDs installed at various locations to determine optimum TED size and placement. Divers found that TEDs installed in skimmer trawls are very similar to TEDs installed in otter trawls with the same factors affecting their configuration and performance. Cable TED evaluations were also conducted aboard a contracted commercial vessel. Divers evaluated various configurations to improve performance of the Cable TED and found that the shape of the lead ring determined the shape of the TED flap. The Cable TED, which was designed as a top opening TED, was also evaluated in a bottom opening orientation. Divers found that the TED was poorly configured as a bottom opening TED and required major modifications to improve performance. Sea turtle exclusion rate trials were conducted aboard the NOAA/NMFS vessel R/V Caretta. This work was conducted to test variations in different components of existing shrimp trawl TED designs to determine their effect on sea turtle exclusion rates. Variations tested included TED angles, TED orientation, straight vs. curved deflector bars, and degree of overlap on double-cover flaps. A total of 163 two year old and 37 three year old captive reared loggerhead sea turtles (Caretta caretta) were utilized to complete this testing. All evaluations followed the small turtle testing protocol (Federal Register, Vol. 55, No. 195). Results indicate that sea turtle exclusion rates for high angle TEDs were lower when TEDs were installed in a bottom opening configuration. Exclusion rates were further reduced for high angle, bottom opening TEDs when configured with straight deflector bars. The R/V Caretta was also utilized to complete evaluations of two BRD designs. One was an industry prototype, the Burbank TED/BRD, which was similar to the original NMFS TED developed in the 1980s. The other was the certified Composite Panel BRD, which was evaluated in two configurations to examine clogging potential with locally obtained brown macroalgae, Sargassum natans. The Burbank TED/BRD had a good configuration with reduced water flow areas located at three locations within the device. The device was recommended for proof of concept testing to examine shrimp retention. The Composite Panel BRD was examined with the addition of a fish deflector cone installed in two different configurations behind the device. The standard two line attachment of the deflector cone was prone to clogging with algae, while an alternative one line attachment reduced clogging significantly. [doi:10.7289/V5JW8BTZ (http://dx.doi.org/10.7289/V5JW8BTZ)]

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