Dolphin population monitoring program: 2009-2010

Dec 21, 2010 No comments By


By Jason Allen, BS, Chicago Zoological Society

We have been able to continue our year-round monthly monitoring of the Sarasota dolphin community thanks largely to support from the Batchelor Foundation and the Disney Worldwide Conservation Fund.  The Sarasota bottlenose dolphin community is perhaps the most thoroughly studied free-ranging dolphin population 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.

Scooter and her new calf

Scooter and her new calf traveling though Sister Key Flats on September 8th.

Photo-identification surveys were conducted on 126 days from November 2009 through October 2010 with the assistance of dedicated volunteers and undergraduate interns. We had 970 group sightings that totaled 3,437 dolphins (including re-sighted animals). Monthly values varied, but overall we averaged about 8 sightings and 27 dolphins per day. These values have remained fairly consistent over the past several years. We had a high of 78 dolphins seen in one day on 18 November 2009. The largest number of dolphin groups seen in one day was 16. One of these groups was our largest seen for the year. The 28 resident SB dolphins in this group included five male pairs, four mother-calf pairs, and ten other well known individuals.

F127, Ginger’s mother, leaps

F127, Ginger’s mother, leaps in Big Pass in April 2010.

We documented the births of seventeen new calves during the summer of 2010 while monitoring the Sarasota dolphin community; this is the most in one year since 1999.  First time moms included: Trisha, Petal, and DABL.  Other new moms included Lightning, FB55, FB79, Scooter, and Allison.  Interestingly, Hair had another baby this summer after having lost her last summer’s baby within a short period of time.  All the young from this summer are still alive and appear to be doing well as of mid-November 2010.

This year, we have accounted for 99% of the dolphins who use Sarasota Bay on a regular basis.  Included among these is Nicklo (our oldest know individual) who had her 60th birthday this year, and F154 (one of our oldest males) who turned 47.  As of October 2010, the number of dolphins regularly using the waters surrounding Sarasota Bay stands at approximately 164 animals.  The only documented loss in 2010 through mid-November was 2252, the 3-yr-old calf of F225, who died from a stingray barb in her lung, and shark bites.

All photos © Sarasota Dolphin Research Program under NMFS permit #522-1785

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About the author

Jason Allen, BS, is the Lab Manager for the Chicago Zoological Society’s Sarasota Dolphin Research Program. He organizes and often conducts the boat surveys of the SDRP dolphin community, while managing the day-to-day operations of the photo-id lab. He also participates in SDRP field activities in the Florida and elsewhere on an as-needed basis.
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