Bottlenose dolphins in Galveston Bay (GB), Texas, live in one of the most industrialized estuary systems in the country. The Galveston Bay Dolphin Research and Conservation Program (GDRCP) monitors dolphin ecology, health and behavior through year-round photo-identification and remote biopsy tissue sampling, and promotes educational awareness. This year our catalog of unique individuals has increased to more than 400 animals, with more than 200 individuals sighted 3-15 times since 2013. Summer and fall bring an increase of dolphins utilizing the upper portion of the bay, while concentrations decrease during cooler months and many of the same individuals are seen utilizing the lower portion of the bay. We plan to further examine movements and historical sightings of individuals in collaboration with the Marine Mammal Behavioral Ecology group at Texas A&M University, who have been studying dolphins in portions of lower GB since the late 1980s.
GB has a history of frequent fresh water influxes and 2015-2016 were particularly wet years, seeing major spring floods that drastically dropped the salinity in the entire bay. After the May 2015 event, we began seeing skin lesions to varying degrees among many members of the population that have continued through to the present time, with an apparent increase in prevalence after the spring floods in 2016. While we believe these lesions to be associated with prolonged fresh water exposure, there is much to learn from what we are seeing and we are currently developing protocols to investigate the problem further. We are proceeding in collaboration with other programs along the Gulf Coast who have seen similar lesions (for example, Christina Toms in Pensacola, FL, (see previous article). Our long-term monitoring program allows us to track the manifestation of lesions on individuals over time. One such case study is presented in the graphic on p. 22. Dolphin #209 shows high site fidelity during warm months in the very upper portion of the bay where salinity changes are strongest. Skin lesions appeared after the 2015 spring floods and developed and changed through the year, presenting a dramatic change after the 2016 floods but quickly healing in the following months. Detailed environmental data including full water column profiles for salinity, temperature, pH, and dissolved O2, are collected during every survey.
We initiated education and outreach activities this year, including a field assistant volunteer workshop and an exciting collaboration with the Houston Zoo to produce graphic booth displays and educational trunks for schools. Increasing awareness of dolphin communities along the Gulf Coast is an essential part of conservation, and we are happy to have the SDRP charting the way as an example and providing training and expertise for new programs such as ours.
The GDRCP is a partnership between the Environmental Institute of Houston at the University of Houston Clear Lake and the Galveston Bay Foundation. Our graduate student researcher and former SDRP intern, Sherah Loe, has worked countless hours helping us to learn about this population and will be completing her master’s thesis on foraging ecology utilizing stable isotope analyses in the coming year. We greatly appreciate support from the Trull Foundation, the SeaWorld Bush Gardens Conservation Fund, Restore America’s Estuaries, the Houston Zoo, Tommy’s Restaurant and Oyster Bar and many other individual donors, volunteers and interns.
This article appeared on pages 21-22 of the 2017 SDRP Annual Report, Nicks n Notches.