As strange as it is, I am already halfway through my time with LAST. It is getting quieter as it becomes the low season here, but we have still had plenty turtles this week. The low volunteer numbers also mean it is time to do some seagrass sampling soon, which I’m excited about.
We were supposed to be out on ocean day at the start of the week but various technical problems with our boats and captains scuppered our plans and we headed out to the mangrove nursery to do some planting in the morning, tackling a beach clean/litter pick on our walk back. In the afternoon we crossed the river and planted two plots.
Luckily our volunteer was able to extend her stay for twenty-four hours and come out on the boat the next day. It was a nice day, with three turtles, a black, a green, and then a hawksbill when we were pulling in the nets. (The scientific community is undecided on whether black turtles are a separate species to greens, a subspecies, or an ecomorph.)
Left volunteer-less once again, a few days this week have been dedicated to deep cleaning the house and catching up on a ton of data entry, which we are now excitingly up to date with. We also went out on an ocean day and managed to get lots of GoPro footage for the project. We had two hawksbills, a small juvenile and an adult male.
It seems as good a time as any to go into the details of how we study the turtles. The net is deployed for 6 hours every ocean day, roughly 8am-2pm. When turtles are caught in the net they are brought onto the boat and wrapped in special turtle straight-jackets, with a damp cloth over their head which helps to keep them calm. We work the turtle on the beach, first weighing it while it is still safely strapped in. When it’s released one person takes each front flipper to hold it still. One or two other people measure while a scribe is recording all the information.
Every measurement is taken three times to reduce errors. We measure the carapace (the ‘top shell’) length and width at the widest point. To measure the plastron (‘bottom shell’) we either put it on its side or back. Only small turtles can be put on their backs as for the larger ones the weight of their internal organs would be too heavy on their lungs. We measure the length and width of the plastron, as well as from the end of the plastron to the tip of the tail, and the cloaca (the universal hole) to the tip of the tail. The tail measurements help to sex adults, as males develop a large tail as a secondary sexual characteristic when mature. There is no quick and reliable way to sex juveniles.
On the hawksbills we count the number of burrowing parasitic barnacles, ‘steph’, in the flippers and shell. A few is normal but very high parasite loads can be an indicator that something is wrong with the turtle and it is floating at the surface more than normal, and not diving to eat. If there is a reasonably high number but not enough to justify taking it to the rescue centre we remove as many as possible while we work.
The invasive procedures are left to the end of the process. The turtles need both external and internal tags. The external tags are metal, one on each front flipper. The internal tag is a PIT, the same microchip used for pet dogs and cats. We have a scanner to check for these. If the turtle is completely untagged we also take a very small tissue sample from the back flipper.
The whole process can take anywhere from five to thirty minutes, depending whether the turtle is already tagged and who is working on it. Then it is strapped back up in its jacket, taken out to reasonably deep water, and let go (preferably away from the net!).