Wednesday, May 30, 2012


This blog was created to allow the public to follow two manatees, Rita and her calf Georgie, as scientists track them after their release back into the wild. Please return for weekly updates.


NOTES FROM THE FIELD – WEEK 5 – this will be the final blog post for this project, please keep up to date with the manatees and all marine mammal research in the Bahamas via our website and facebook page.



24-May-2012

Scattered thunderstorms prevented Willie and Kendria from heading out to check on Rita and Georgie. Around mid-day, a local fisherman notified Kendria that he saw Rita and Georgie in the T-canal. Kendria was able to ride over there and caught a quick glimpse of the two tagged manatees.  Rita and Georgie stayed in Great Harbour Cay harbour for the remainder of the day.  

25-May-2012

Using the H-antenna and receiver, Kendria was able to pick up fairly loud VHF signals from Rita’s tag. She decided to walk around the harbour and track the tagged ladies by foot. The loudest signals received led her to the south end of the T-canal. Once at the southern tip of the canal, Kendria was able to narrow her search for Rita and Georgie to the northern side of the canal where she spotted them.

At 11:30am, Rita and Georgie were observed traveling towards the entrance of the T-canal but quickly turned around and continued to the northern side of the harbour. They have been observed feeding on the seagrass beds there on numerous occasions, so it was no surprise that they spent the next two hours in this area.


A layout of Great Harbour Cay harbour. The Causeway connects Great Harbour Cay to Bullocks Harbour; it is under this bridge that the manatees can gain access to the mangroves on the other side of the harbour.


26-May-2012

Early morning Argos satellite locations showed that Rita and Georgie began a journey north towards Lignum Vitae Cay. The route they took this time was very different than before! They travelled under the Great Harbour Cay harbor causeway and through the mangroves up to Lignum Vitae.

By 10 am, the tagged ladies had traveled along the eastern side of Great Harbour Cay towards Hawksnest Cay continuing south to Holmes Cay and Hoffman Cay. They remained in this area for the rest of the day!


27-May-2012
An Argos satellite location received at 4:54am indicated that Rita and Georgie were still at Hoffman Cay, South Berry Islands. This was the second time that they traveled this far south.  South Berry Islands are connected by a shallow bank with extensive seagrass coverage with very little to no boat traffic on a daily basis; it is a suitable area for manatees to travel and hang out.

  

28-May-2012
  As a goodbye gift, I (Kendria) got to see Gina and her calf, JJ and the adult male today in the marina. All three manatees appear to be in good health and were observed drinking water from the ice machine pipes. Gina looked quite different as she was no longer completely covered in brown algae but JJ was still covered in brown algae.

Meanwhile, Rita and Georgie took a short trip to Little Harbour Cay and back up to Hoffmans Cay by 10am. Traveling along the east side of Amber Cay, Rita and Georgie made their way back north along the east side of Great Harbour Cay. By 3pm, they had traveled approximately 30km (16nmi) north to Lignum Vitae Cay.  

BMMRO would like to thank everyone involved in this project for their support and assistance. This wouldn’t have been a success without everyone’s cooperation!

Jim Reid (USGS-Sirenia Project)
The Department of Marine Resources
The staff of Atlantis Dolphin Cay and the Water Features Department
Save the Manatee Club
Olivia Patterson (Friends of the Environment)
Matt McCoy (Loggerhead Productions)
Kelly Mellio-Sweeting (Dolphin Communication Project)
Beth and Tim Cook
Frenchie and Tom
Elorn of Happy People
 Joe (Great Harbour Cay Marina Office)
David Wineberg
 The Kalis Family
Jimmy, Percy and Chester Darville
R.N. Gomez All Age School
Lana and Jeff Foreman
Desiree Messier
Willie Bonner & Bruce
Franny Cable of Colorado
To our friends from Hope Town and Spanish Wells thank you for your donations and endless support

And last be surely not least…the people of Great Harbour Cay,
thank you for having so much pride and love for these amazing mammals!








A plot of the locations of Rita and Georgie via Argos satellite shows their sixth weeks' movement around Great Harbour Cay; arrows indicate direction of travel from Great Harbour Cay harbour to Little Harbour Cay in South Berry Islands and back to Lignum Vitae Cay, North Berry Islands.


Posted by Bahamas Marine Mammal Research Organisation at

Manatee Acoustics


Marine mammals such as dolphins and whales use sound to communicate, locate prey, navigate, and avoid predators. Today, a lot more is known about the types of sounds these mammals use in order to communicate with each other. 

But how do manatees communicate? 

What are their different vocalization patterns? 

Although they are also marine mammals, manatees socialize and communicate very differently from other marine mammals. Along with dugongs they are the only herbivorous marine mammals in the world and the closest relatives to the largest land mammals, elephants. Often described as semi-social, very little is known about their acoustic behavior and whether they use sound as a form of communication.  


DSG Acoustic Recorder
To help us understand how these agile species use sound, we placed a DSG (digital spectrogram) acoustic recorder in Great Harbour Cay marina. The acoustic recorder was programmed to record the low frequency sounds produced by manatees, which are often described as chirps, whistles, or squeaks. Scientists have been able to link some of their sounds to represent signs of aggression or fear (Listen to Manatee Sounds).  Mother and calf pairs are known to share the most vocalizations patterns although an increase in vocalization patterns have also been heard between different age classes during socializing behaviors such as rolling, pushing or embracing (MANATI). 

Much like how dolphins can be identified from their signature whistles, scientists will be looking at identifying individual manatees from the sounds they produce. In February 2012, while Rita and Georgie were at Dolphin Cay-Atlantis we recorded their vocalizations to compare those vocalization patterns to those recorded of them in the wild.




Below are the acoustic profiles for three types of sounds detected, while recording Rita and Georgie on May 1st, 2012.

Sound Category: Creak






























Sound Category: Scream






Sound Category: Whistle


















Works Cited

MANATI, S. D. (n.d.). Animal Bioacoustics . Retrieved May 23, 2012, from Caribe Bioacoustics and Noise (CABN): http://www.cbanpr.com/manatee.html
 Listen to Manatee Sounds. (n.d.). Retrieved May 23, 2012, from Save the Manatee Club: http://www.savethemanatee.org/audio.htm


Resources:
Manatees, Bioacoustics and Boats: Hearing tests, environmental measurements and acoustic phenomena may together explain why boats and animals collide



Posted by Bahamas Marine Mammal Research Organisation at
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