Sarasota Dolphin Research Program

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Sarasota Bay dolphin community monitoring program 2008-2009
By Jason Allen, BS

F256 (foreground) and Annie (background) shortly after their health assessment in May 2009. F256 is the great-great grand calf of FB43, and he was the first known 5th generation dolphin to be briefly handled and studied by our researchers.

We have been able to continue our year-round monthly monitoring of the Sarasota dolphin community thanks largely to support from NOAA Fisheries Service and Disney’s Animal Programs. The Sarasota bottlenose dolphin community is the most thoroughly studied free-ranging dolphin community in the world. We continue to address increasingly refined questions about the lives of these animals with the benefit of information gained through our intensive year-round studies of their distribution, social and reproductive patterns.

Photographic-identification surveys were conducted on 126 days from November 2008 through October 2009 with the assistance of dedicated volunteers and undergraduate interns. We had 1,065 group sightings that totaled 3,135 dolphins (including resighted animals). Monthly values varied, but overall we averaged about 8.5 sightings and 25 dolphins per day. These values have remained fairly consistent over the past several years; though we were able to survey on more days this year than in any of the previous ten years. We had a high of 18 dolphin groups sighted on September 4th and October 28th. The most dolphins seen during one day was 81 on May 13th. Not surprisingly, this day also had the largest single group of Sarasota Bay community members. The 18 dolphins in this group included FB44, Bark, Scrappy, Thrasher, Boxer and calf, Annie and calf, C835 and others.

Killer and her new calf surfacing along the Anna Maria Island coastline, 10 August 2009.

We documented the births of eight new calves to resident mothers during the summer of 2009. F215 was determined by ultrasound to be pregnant during health assessments and had her first calf later in the summer. Allison also had her first calf, while Hair had her third and Pumpkin her sixth. Sadly, the carcass of Allison’s calf was recovered, and the other two new calves have not been observed recently and are presumed dead. Other mothers with new calves in 2009 include FB25, Killer, FB93, and Murphy Brown. Their young are still alive and appear to be doing well.

We accounted for most of the expected long-term residents of Sarasota Bay. Unfortunately, we confirmed the deaths of four long-term community members this year. Two of these were a couple of our longest-known individuals; FB05 (a 46-year-old female observed since 1971) and FB13 (a 50-year-old female observed since 1975). We also lost Pumpkin, the 1984 calf of Ms. Mayhem, along with her newborn. Finally, we recovered the 2006 calf of Scooter (1091) who likely died of overeating. Necropsy results showed that she had eaten so many fish that she literally could not swallow another and choked to death. The carcass of a 33-year-old male (FB68) known from waters north of Sarasota Bay was recovered by the state’s Marine Mammal Pathobiology Lab, with recreational fishing gear deeply embedded in his upper jaw.

Long-term volunteer John Hamilton helps take identification photos during a sighting in Palma Sola Bay, 10 October 2009.