Photos From the Field

                Wednesday, May 1, 2002

   

While looking for sea turtle nests this morning, a ghost crab ran just in front of my toes.  Can you make a conjecture as to why they are called ghost crabs? These ghost crab holes, which serve as their homes, are scattered about every few feet on the beaches here in Sarasota.
Teresa and I are up in the boat tower during the two hour observation at the Buttonwood Harbor site. She is taking pictures for the photo identification study. I am busy carefully recording data, which has to be completed both accurately and quickly with so many manatees around. This manatee, who was ID# 501C today, is showing us his left side which was obviously involved in a boating accident. Teresa indicated that the criss- cross scars you see are truly superficial and may heal with little permanent scarring. This can also pose a problem during a photo identification study, can you determine why?
This is a shot of just one of the manatees that was frightened by the floating manatee who bumped our boat.  The waves left out to the side of him should give you some indication of the speed and strength of an adult manatee.  Imagine the entire sight from my tower, with ten of them swimming away in every direction. One of the signs we look for when performing a boat survey is sea grass floating on the surface.  If you look closely you can see some turtle grass and shoal rising to the top of the water.  When manatees are grazing below, many pieces of grass are freed from the bottom, and float to the top.  If we notice this phenomenon we generally stop the boat and wait to see if any manatees come up to breathe.  With the glare on the water it is just as difficult for us to see the sea grass in the field, as it is for you to see it in this picture!
When looking for a manatee in murky water, it is difficult to see the gray skin on their bodies.  We tend to look for scar patterns since they are usually white.  This manatee here was 501A, the first photo identification we made today.  We were able to track his movements in the murky water by focusing on this white scar markings. Another method for judging the direction a swimming manatee is heading in, is the observation of "footprints".  The up and down movement of the paddle-shaped fluke forms oval shaped indentations in the water's surface.  The smallest footprint is closest to the manatee, so we can use these to indicate his path in the water.  Do you think the manatee is swimming towards the house on the right hand side of the picture or towards the boat?
After being up in the observation tower for a few hours, Teresa and I needed some food and extra protective clothing in order to continue our survey.  It is helpful to have extra people down below who can hand things up to you, since you cannot leave the tower during a sighting.  For validity and consistency in the data, the same people must complete any sighting incident they start, even if the manatees remain in that location for hours.

 

 

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