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Population dynamics and movements of the Kemp's ridley sea turtle, lepidochelys kempii, in the northwestern Gulf of Mexico

The Kemp’s ridley sea turtle, Lepidochelys kempii, is recovering from
devastating declines that reduced nesting activity from a single-day estimate of 10,000-
40,000 females in 1947 to fewer than 300 during all of 1985. Nesting beach monitoring
is crucial to estimating population size and reproductive activity, but in-water data are
essential for understanding population dynamics and evaluating management strategies.
Hook-and-line, stranding, and nesting records, satellite telemetry, and diet
analyses were used to characterize ridley population dynamics and movements in the
northwestern Gulf of Mexico during 2003-2007. Recreational hook-and-line captures
comprised approximately one third of non-nesting encounters along Galveston and
Jefferson Counties, Texas. The hook-and-line dataset displayed similar geographical and
monthly trends to that of strandings, but was devoid of pelagic-stage, subadult, and adult
ridleys.
Coastal and bay waters along the upper Texas and western Louisiana coasts were
utilized by immature ridleys during warmer months. Nesting occurred along Galveston
Island on both armored and unarmored beaches. Inter-nesting females exhibited fidelity
to Galveston during nesting season and subsequently migrated to federal waters offshore
Louisiana. Crabs were important components of benthic-stage (>25 cm SCL) ridley diet,
while worm tubes were targeted by some individuals. Short satellite track durations for immature ridleys precipitated examinations of
biofouling, attachment protocols, and turtle excluder device (TED) interactions.
Antifouling paints drastically reduced fouling of transmitters. A less-rigid neoprene
attachment method was developed to increase transmitter retention on fast-growing
juveniles, but further trials are necessary. Transmitters were not damaged or lost during
TED trials, but turtle escape times increased when transmitters wedged between TED
bars.
Projected population growth will increase numbers of Kemp’s ridleys utilizing
the Gulf of Mexico and interacting with human activities. Future research should
examine year-round distribution and abundance of all life history stages and further
characterize recreational hook-and-line capture, nesting activity, movements, and diet.
Education efforts targeting the beach-going public, beach residents and workers, and the
recreational fishing sector should be employed to promote sea turtle reporting and
minimize negative interactions. State and federal managers should examine
anthropogenic impacts within the region and determine the need for mitigation and/or
regulations to promote continued species recovery.

Identiferoai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2375
Date15 May 2009
CreatorsSeney, Erin Elizabeth
ContributorsLandry, Andre M (Jr.)
Source SetsTexas A and M University
Languageen_US
Detected LanguageEnglish
TypeBook, Thesis, Electronic Dissertation, text
Formatelectronic, application/pdf, born digital

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