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Journals 2008/2009

Zamaria Rocio
Horace Mann Middle School, San Diego, CA

"Marine Biodiversity of the Great Barrier Reef
(Heron Island Research Station)"

August 25 - September 14, 2008
Journal Index:
August 24 - 25 - 26 - 27 - 28 - 29 - 30 - 31
September 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 10
                 11 - 12 - 13

September 3, 2008
Ray Sighting At 8 am

Most mornings I am in the laboratory by 7 am so I may talk via my computer to my family and friends. However, this morning was unusual because when I got to the laboratory, only a few people were there and they said the rest of the group were down by the dock looking at the rays that had come close to the shore. I grabbed my digital camera, which was always close at hand and ran the 40 meters to the beach area. I could not believe what I was seeing. There were dozens of rays close to the shoreline. It was high tide and visibility was very good because the rays were not concealing themselves beneath the sand. A few people wearing their snorkels and wetsuits came within a meter of this group of Pink Whiprays (Himantura fai). These rays would then swim away, circling back around the pier and settling down once again in the shallow water near the shore. I was very intrigued by the interaction between the people and the rays that I must have been there for over an hour.

Rays are known as Elasmobranchs along with the sharks. Of all the species of rays found around the world, over 70% are endemic to Australia. They have cartilaginous skeletons and ventral gill slits. Rays also have one or more spines on their tails. These spines are serrated and are used for self-defense mostly against sharks. Over half the ray species have venom glands associated to these spines. The rays I was seeing today were called whiprays because of their long thin tails. These adult rays can measure 130 to 160 cm across and about 150 cm in length. Finally, as if these rays got tired of playing this game of "try to catch me if you can," they were gone. How fortunate I was to be part of this event even though I was just an observer.

Whiprays close to the shore and people

I had another coral head to work up today. This one took over three hours from start to finish because I was working by myself. It has been very interesting to look at what is on and in it. I try to guess what I will find before I look at it. I slowly clip away the head being careful not to smash any organism. Most of the time I am lucky. But always I come away with some new species I had not seen before and I am excited to bring it back to the laboratory to show Laetistia. Decorator crabs were plentiful today. They were crawling around the coral head and trying to hide among the algae on it. I think it is quite interesting that these crustaceans would take pieces of algae and attach it to their carapace. At the lab, all the crabs and other organisms I got were grouped by species in plastic containers. If necessary, the dissecting microscope was used to help do this. For the DNA analysis on the crabs, only one hind leg was taken and placed in the vial. Everything was recorded on a spreadsheet.

Decorator Crabs