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:
17-May-2012
Scattered thunderstorms
prevented Willie, Beth and Kendria from going out early to check on Rita and
Georgie but finally by 4pm, the rain had held up just enough to search for the
tagged manatees. After traveling for over 70 miles around Great Harbour Cay to
the south and back, they had safely returned to Bullock’s Harbour. We found
them with the adult and juvenile male and observed them feeding on seagrass
beds. Georgie remained very close to her mother, Rita, as they were feeding and
socializing with the other manatees.
We are able to track the
manatees using two methods: signals received using a VHF radio receiver and
through locations derived from satellites passing overhead. These can be
downloaded from Argos’ website throughout the day and, unlike the radio
receiver isn’t dependent on us being within receiver range of the animals which
isn’t always possible because of bad weather conditions. If the animals are not
within radio range, using a combination of both methods can be best; first
check the Argos location, then travel to the general area and use the VHF
receiver to actually find them.
Argos categorizes satellite
locations received from their tags by ‘quality code.’ These codes are
essentially a measure of location (latitude and longitude) accuracy. Accuracy
is affected by how much of the tag’s transmitter is above the water’s surface
as a satellite passes overhead and also how many satellites passing overhead
picked up the same transmission. Accuracy can range from 100 meters to tens of kilometers
so close attention must be paid to the quality code (Deutsch et al. 2003).
Works Cited
Deutsch, C. J., Reid,
J. P., Bonde, R. K., Easton, D. E., Kochman, H. I., & and O'Shea, T. J.
(2003). Seasonal Movements, Migratory Behavior, and Site Fidelity of West
Indian Manatees Along the Atlantic Coast of the United States. The Journal
of Wildlife Management: Wildlife Monographs 151 , 1-77.
