ARCHELON vignettesElizabeth Willis ‘13 | July 29, 2010
Night Survey with Backof
On my first night survey at ARCHELON, I was scheduled to work with Tom Backof and Hannah Sintek. Tom was working on an independent research project in which he fastened data loggers and a radio transmitter to a turtle. This was used to acquire data about the turtle between nesting, such as where she migrated to, as well as water temperature and pressure per unit time, which gave valuable information about the turtle’s life in the sea, depth of dives, and possible sleeping habits. I found all of this very interesting, so accompanying Tom on my first night survey was definitely a privilege.
We came across a turtle pretty early in the night. While she laid her eggs, Tom was busy setting up his equipment and giving Hannah and me last-minute directions. The turtle was untagged, so the plan was to tag her after installing the data logger and transmitter. As soon as the turtle finished laying and started covering her nest, we got to work. First, we injected a PIT tag into the turtle’s shoulder and then Tom drilled two holes into the turtle’s carapace, one in the middle of the back end and one off to the right side. He fed a needle with surgical tubing through the hole, passed fishing line through it and fastened the data logger to the hole on the right side. When he started to do the same for the transmitter on the back hole, the needle with surgical tubing wouldn’t fit through the hole. So we opened up the hole a little wider with the drill and tried again. It still did not work; three needles broke and we had to make some more. (By needle, I basically mean a thin piece of fishing wire tied to the surgical tubing, which can be fed through the hole and used to pull the surgical tubing through.)
At this point, the turtle was getting really antsy. She was finishing up with covering and camouflaging and getting ready to go back to the sea. As Hannah and Tom worked to make some more needles, I turned around just in time to see the turtle leave her nest. “Uh, Tom do you want me to restrain her?” “Yes! Try to keep her quiet and high on the beach so I can get the transmitter on.” Unlike in Kefalonia, ARCHELON does not allow turtles to be flipped but we do restrain them by carefully placing hands over their eyes and gently but firmly pushing their head into the sand. So I set off after the turtle to restrain her. She was quiet in the beginning, but as Tom finally got his transmitter on and fastened, she decided she had had enough. She started turning around in circles and using her flippers to smack my arms out of the way. She even tried to bit me now and then, opening and closing her mouth as I kept myself at a safe enough distance while still able to hold her eyes closed.
After a frustrating 15 minutes of being jostled around by the turtle, Backof managed to wrap up the installation of his equipment, get a metal tag into her front flipper and finally we relaxed. We didn’t get any carapace measurements or put in a plastic tag, but the night was eventful enough and I ended up with quite a few scrapes and scratches along my arms from being smacked around by the fed up turtle. It was definitely worth it though!
My first nest excavation
Nest excavations happen 9 days after the nest first hatches, or 70 days after the lay date if there is not hatchling activity. We excavated our first nest, A1 (the first nest laid on A Sector) on July 22nd. Tom Riggall, our monitoring project leader, led the excavation and handled the eggs to show us how it is done and explain the process. A1 turned out to be a very smelly nest. The bottom layer of eggs had contracted some sort of bacteria and rotted, but most of the eggs hatched successfully.
As soon as we cleared away the top layer of sand, Tom took over and dug out the rest of the egg chamber. We cleared a flat area of sand next to the nest, where Tom deposited all the eggs and eggshells, which we then classified and laid out in rows of ten. First we distinguished the hatched eggs from unhatched eggs; the hatched eggs are clean and dry on the inside, whereas unhatched eggs are yolky and containing traces of blood. Then within the category of unhatched eggs, we separate the eggs into three groups: unhatched eggs with no visible embryos, unhatched eggs with dead embryos, and unhatched eggs with live embryos (this last category gets reburied to hatch later). The category of unhatched eggs with dead embryos gets subdivided further into eyespots, early, middle and late stages of growth. We also write down the number of live hatchlings found in the top 10cm of the nest, live hatchlings in the rest of the nest, dead hatchlings, and live or dead pipped hatchlings, which have come half-way out of the egg.
Once Tom had cleared everything out of the egg chamber, we recorded the bottom depth of the nest and began to classify the eggs. We came across 70 hatched eggs, 36 unhatched eggs with no visible embryos, 40unhatched eggs with dead embryos and three dead hatchlings. The whole excavation with Tom’s explanation took between half an hour and forty minutes and even though it was smelly (Tom said most nests are usually much cleaner than that one!) it was worthwhile and very educational.
Inundations and my first live hatchling
A few days ago we had some stormy weather (but no rain) with a very high tide. A lot of nests on all sectors of the beach got inundated or partly washed over by the waves. This created more work for the morning survey teams, as we had to check every nest and dig it out if it had been heavily inundated. I was on A Sector that morning, which is the beach with the highest concentration of nests of all the sectors that we monitor. By the end of morning survey, we had dug out 41 inundated nests and 18 nests that had been partly washed over by the waves. Some nests were buried under at least 25 cm of sand, while others were left almost exactly as they were. With all washed and inundated nests, you have to make sure that the sand under the grid is loosened so that when the sand dries it doesn’t form a hard sheet that could prevent hatchlings from exiting the nest.
About three-fourths into morning survey, we came across a nest that had just hatched the day before, A4. When we found it, it had be inundated and heavily predated by a dog from the front, where the waves had dragged out some of the sand. My team and I had been eagerly looking for the nest because we were hoping to see some hatchling tracks and if possible a few straggling hatchlings. When we saw all the paw prints and the empty eggshells, we all pretty much fell quiet because we didn’t think any hatchlings had made it the water during the night. I sent Emma to go dig a hole at the back of the beach to bury the empty eggshells and Maria, Mario and I started collecting all the eggshells we could find to get a count on the number of eggs that had been predated. Since the nest had hatched the day before, we had to conduct a mini excavation and differentiate between hatched and predated eggs. Maria and I sorted the shells and then I decided to check the nest for anything that we had missed. I found a few more empty shells and just as I was withdrawing my hand from the nest, I felt some movement against one of my fingers and seconds later a little hatchling head popped out of the sand! I was so shocked and excited that I breathlessly yelled hatchling to the rest of my team and we all gathered around to marvel at the little baby. It was so small, but it was incredible to see it fully formed with all its scutes and flippers and a tiny egg tooth. We buried the hatchling again to allow it to come out at night when it was cool rather than let it get dehydrated and possibly die walking in the sun.
Seeing the live hatchling made us all feel a lot better. When we counted the predated eggs, we found 24 hatched eggs and 20 predated ones, so we felt even better that quite a few had made it out of the nest. A live hatchling is so different from an adult turtle. In terms of size, the difference is tremendous but hatchlings also look so fragile and soft compared to the adults, which have such big, hard shells and so much strength. Finding a predated nest that is still hatching and encountering a live hatchling within the nest really put things into perspective for me. Our conservation work is definitely making a difference and giving more hatchlings a chance of survival. At the moment, the beach that we monitor here in Kyparissia has 815 nests. This is the largest number of nests that these beaches have seen since monitoring began; we broke the highest record of 779 nests and we expect to surpass 850 if not 900 nests by the end of the season as we encounter nests missed on morning surveys that we find by hatching or by predation. This surge in the number of turtles we have seen and tagged and the number of nest we have had this year can only be attributed to the conservation work that started on this beach 25 years ago. We are in fact making a difference here, and the turtle population of Kyparissia is increasing. Zakynthos, Kefalonia and Crete are experiencing a plateau in the decline of turtles, and they hope to see an increase soon, but here in Kyparissia we are already noticing the benefits of our work. It is so exciting to know that we are all making a positive difference and it is having fantastic effects!