Updated abundance estimates for common bottlenose dolphins (Tursiops truncatus) inhabiting West Bay, Texas

Abstract

Abstract West Bay is located along the south‐west portion of Galveston Bay, Texas, and has been delimited as a bay, sound, and estuary (BSE) common bottlenose dolphin (Tursiops truncatus) stock area under the Marine Mammal Protection Act of 1972. The most recent abundance estimate available for the West Bay BSE stock is from 2001 and is considered outdated for management purposes. This study provides an updated abundance estimate using photo‐identification capture‐mark‐recapture (CMR) data collected from West Bay during the winter of 2014 and summer of 2015. The CMR data were analysed using both Pollock's robust design models and Poisson‐log normal mark‐resight models. Differences between the model types are discussed, and the abundance estimates derived from the mark‐resight models are recommended for management use (50.63 [unconditional SE 2.23] in the winter and 44.36 [unconditional SE 1.18] in the summer). Whereas the updated abundance estimates are higher than the previously reported estimates, which varied between 28 and 38, they still indicate that West Bay supports a small population of bottlenose dolphins. As a result, the West Bay BSE stock should be closely monitored for impacts, particularly those related to human caused stressors.