Abundance of bottlenose dolphins (tursiops truncatus) in Texas coastal bend




Wilkins, Allison
Orbach, Dara N.


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Bottlenose dolphins (Tursiops truncatus) are the only species of marine mammal residing in the Texas Coastal Bend and have been specifically identified as imperiled by the National Oceanic and Atmospheric Administration. It has been almost 40 years since research has been published on the local population of bottlenose dolphins. In recent decades, the Texas Coastal Bend has substantially expanded in industrial growth and the Port of Corpus Christi is the third largest port in crude oil exportation in the U.S.A. The Corpus Christi Shipping Channel is also undergoing continual dredging to widen and deepen the channel to attract more commercial and industrial developments. With increasing and rapid changes and associated threats, it is important to monitor the local population of bottlenose dolphins and quantify how they are impacted by anthropogenic disturbance to inform policymakers for conservation mitigation. The population abundance of dolphins inhabiting the Texas Coastal Bend was determined by counting the number of animals based on unique markings. Photographs were captured of the individually distinctive dorsal fins of dolphins from a research vessel during 45 survey days since 2018. Photographs were subjected to quality control checks, cropped, matched by a minimum of two researchers, and scored based on quality. Preliminary results show that the current population of bottlenose dolphins consists of over 1,300 individuals, indicating a substantial population growth from the 593 dolphins reported in 1983. Findings from this study and additional photo- identification surveys will provide insights on the stability of the population that can be used as baseline data for conservation, including if dolphins are year-round residents and frequently inhabit areas of high vessel traffic.



Population abundance, bottlenose dolphins, photo-identification, texas



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