HOUSTON – On Aug. 25, 2017, Hurricane Harvey made initial landfall on the central Texas coastline. Following the historic flooding, researchers undertook a case study describing the effects of Harvey on bottlenose dolphins inhabiting the upper Galveston Bay.
According to a study by the Galveston Bay Dolphin Research Program (GDRP), researchers observed a 73 percent drop in bottlenose dolphin encounter rates in the upper Galveston Bay and freshwater skin lesions were found on 96 percent of the observed dolphins.
In the recently published journal “Estuaries and Coasts,” researches compared dolphin encounter rates for the months preceding and following Harvey to a year with no hurricane, examined shifts in habitat-based encounter rates, and evaluated the prevalence and extent of dolphin skin lesions.
The journal states encounter rates decreased from 1.09 dolphins per linear kilometer (d/km) in August 2017 before Harvey to 0.29 d/km in September 2017. While most dolphins evacuated the upper portion of the bay, many remaining dolphins shifted habitats from shallow open bay to deep channels where salinity increased with depth.
Of the dolphins that were sighted in the upper bay during the low salinity event, 96 percent exhibited at least one lesion and 65 percent of those dolphins had lesions of medium or high extent (significant increases compared to pre-Harvey levels).
Approximately eight weeks after Harvey when salinity returned to levels above 11 ppt, encounter rates increased and the extent of lesions decreased, but the prevalence of lesions remained elevated for at least 4 months after Harvey. The complete study can be read here.
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Houstonians can support this research by virtually adopting or naming one of the special bottlenose dolphins that call the upper Galveston Bay home..