Sarasota Dolphin Research Program

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Bottlenose dolphin health assessments in Sarasota Bay
By Randall Wells, PhD

We resumed dolphin health assessments in Sarasota Bay in 2008, conducting operations on six days in May. The project, again sponsored by Dolphin Quest, involved the efforts of 99 people from the United States, Argentina, Bermuda, Brazil, Canada, and Scotland. With about 70 people on the water in nine boats each day, we captured, examined, sampled, measured, and released 13 dolphins (9f:4m), ranging in age from two to 24 years, and including five handled for the first time. One experienced dolphin was determined to be pregnant, and as a result she was not brought aboard the veterinary examination vessel and did not undergo the full sampling and measurement routine. She delivered a healthy calf one month later, which is doing fine as of January 2009.
The primary purposes of the capture-release program were: 1) to continue our investigation of seasonal changes in concentrations of environmental contaminants as part of our ongoing study of the dynamics and role of environmental contaminants in dolphin health; 2) to sample and mark 2-4-yr-old calves of well-known mothers before they leave their mothers; 3) to complete sampling of other individuals for which one or more samples are needed; and 4) to facilitate any other high quality research that can be accomplished without placing the dolphins at additional risk. Data, samples, and/or measurements were obtained from each animal in support of 29 different projects in the areas of health assessment, environmental contaminants, biotoxins, life history, population structure, ecology, hearing, and communication.

Two dolphins are readied for release following health assessment in May 2008.

Of particular interest this year was information on body condition. During the June 2006 health assessment, following the severe red tide of 2005 when the dolphins’ prey fish were drastically reduced, dolphins were in poorer body condition than in most years. This was especially evident for calves, with an average 23% decline in mass. In 2008, body mass index values had returned to normal levels. Red tide has been largely absent from Sarasota Bay for more than a year, and fish stocks have returned to pre-red-tide levels.
It is not clear if it will be possible to conduct planned health assessments in Sarasota Bay in 2009. We recently learned that due to the economic situation, our principal funding source for this project will not be able to provide the needed support.