A project of Mote Marine Laboratory.
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Movement of whale shark ('Sara') after tagging with a SPOT5 satellite tag.
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Species: Whale Shark
Life Stage: Sub-Adult
Release Date: 2010-05-28 15:12:00
Release Location: Gulf of Mexico - Off Sarasota
Last Location: 2010-08-20 03:28:04
Tina & Suzannah Koser
On May 28, 2010, Mote's Center for Shark Research was notified of two whale sharks (Rhincodon typus) on a reef just a few miles off Sarasota, FL. After quickly mobilizing a field team to document this rare sighting, the researchers located one male and one female whale shark not far from the reef and began making detailed observations. The shark team attached a SPOT5 satellite transmitter to the 7 m female (nicknamed 'Sara'). A 7.5 meter male shark (named 'Sota') was also tagged but with a different type of satellite tag (Mk10 PAT) that archives data and then sends that information to the researchers via satellite once detached from the shark after a specific duration (90 days).
Dr. Bob Hueter of Mote's Center for Shark Research prepares to apply the satellite tag to whale shark 'Sara'.
Mote intern Lacie Carter observes 'Sara' from the research vessel.
Update on Sara (as of Aug 23, 2010)
For five weeks, Sara’s SPOT5 satellite transmitter provided Mote CSR researchers with excellent location data revealing movements confined to the offshore waters of the Florida Gulf. Her initial travels away from the Sarasota area brought her south to an area about 75 km off Sanibel Island. This was followed by northward travels bringing her back through the vicinity of her tagging and then to an area about 100 km off Crystal River, FL. It was around this time (July 2) that the pattern of data we were receiving from Sara’s SPOT5 tag changed. For example, the transmitted temperature data became relatively constant after this point indicating that the tag was no longer going down into colder deeper water, a pattern typically expected for a tag attached to a whale shark. After carefully analyzing these and other data transmitted in subsequent days, Mote CSR scientists concluded that Sara’s tag must have detached from her. Although disappointing, this is not an uncommon event when tracking sharks using this type of technology and the unfortunate detachment may have occurred for any number of reasons. The floating tag continued to transmit location information for several more weeks as it moved at the mercy of wind and currents. At one point the tag floated to where it was within 20 km of Sarasota. We have since “turned off” the satellite service receiving signals from this tag. But we still hope to recover the tag if possible to learn how and why it may have detached and perhaps improve our satellite tag attachment methods.
Additional facts about Sara and whale sharks in general:
* With lengths of 14 m (45 feet) or more, the whale shark is the world's largest living fish and yet it subsists on tiny prey items called plankton.
* Apart from their enormous size, whale sharks can be identified by their unique 'checkerboard' pattern of light-colored spots and stripes.
* To strain plankton from seawater, whale sharks use a unique filtering method that utilizes specialized filter pads located in their throats.
* Although 'Sara' was estimated to have a total length of 7 m (23 ft), she's probably not quite sexually mature yet.
* Female whale sharks reach sexual maturity at about 8-9 m (26-29 feet) in length and can deliver as many as 300 pups.
* Whale shark pups measure about 60 cm (2 feet) at birth. The duration of the gestation period is still unknown.
* Very few newborn (free-swimming) whale sharks have ever been captured and the precise areas where they are born are still unknown to science, as are the locations of whale shark mating in the ocean.
* Whale sharks are found in tropical and warm temperate seas around the world and are capable of migrations of many thousands of kilometers.
* Although usually observed in surface waters, whale sharks regularly dive to depths in excess of 1000 m.
* The whale shark is currently listed as 'vulnerable' on the World Conservation Union (IUCN) Red List of Threatened Species.