Chemoreception in Loggerhead Sea Turtles: An Assessment of the Feasibility of Using Chemical Deterrents to Prevent Sea Turtle Interactions with Longline Fishing Gear
نویسندگان
چکیده
The mission of the National Oceanic and Atmospheric Administration (NOAA) is to understand and predict changes in the Earth=s environment and to conserve and manage coastal and oceanic marine resources and habitats to help meet our Nation=s economic, social, and environmental needs. As a branch of NOAA, the National Marine Fisheries Service (NMFS) conducts or sponsors research and monitoring programs to improve the scientific basis for conservation and management decisions. NMFS strives to make information about the purpose, methods, and results of its scientific studies widely available. NMFS= Pacific Islands Fisheries Science Center (PIFSC) uses the NOAA Technical Memorandum NMFS series to achieve timely dissemination of scientific and technical information that is of high quality but inappropriate for publication in the formal peer-reviewed literature. The contents are of broad scope, including technical workshop proceedings, large data compilations, status reports and reviews, lengthy scientific or statistical monographs, and more. NOAA Technical Memoranda published by the PIFSC, although informal, are subjected to extensive review and editing and reflect sound professional work. Accordingly, they may be referenced in the formal scientific and technical literature. ABSTRACT The mechanisms by which sea turtles are attracted to and become hooked and entangled in commercial fishing gear are not well understood. Identification of sensory attractants and repellants may prove useful in developing gear and bait modifications to reduce sea turtle bycatch in commercial fisheries. We conducted experiments to investigate the ability of loggerhead turtles (Caretta caretta, Linnaeus 1758) to use chemical and flow cues to successfully locate squid bait and also tested to see if chemical modification of squid bait would reduce the turtles' ability and/or willingness to track and locate bait. Captive-reared juvenile loggerhead turtles were placed in a seawater-filled flume tank with a current of 3–5 cm·sec-1. A nylon bag containing either nylon (control), squid, or squid that had been marinated in 2-phenylethanol or shark-derived compounds was placed in the current upstream from the turtle. Trials were conducted in darkness, and the behavior of turtles was monitored and recorded using an IR-sensitive video surveillance system. The presence of squid bait in the tank elicited feeding and searching behavior; however, turtles showed limited ability to locate squid bait in the absence of visual cues. Only 25–33% of turtles located and ate the squid bait during the 10-minute trial period. These results indicate that visual cues are important for foraging success in loggerhead turtles, and chemoreception likely …
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