Ascension : Conservation Weekly - TURTLES HATCH AT THE CONSERVATION CENTRE
Submitted by The Islander (Conservation Office) 22.05.2008 (Article Archived on 05.06.2008)

Hi. Here’s just a quick update on some of the work that is going on at the Conservation Centre. This year, in association with the Conservation team, I am doing some research to understand why some clutches of turtle eggs hatch very successfully while in others most of the eggs die.

 This is interesting on Ascension because some beaches, like Long Beach, produce very good hatching success while nests on others, like North East Bay, are generally much less successful. To help understand why we have set up sets of incubators at the conservation centre (made out of polystyrene crates kindly provided gratis by your local NAAFI store), with some set at a temperature similar to Long Beach (about 29ºC), and others set up at the warmer temperatures found on North East Bay (about 32.5ºC), but with everything else kept exactly the same. We then take eggs from a number of laying turtles and split them up with some at the warmer temperature and some at the cooler temperature and see how the hatching success compares. So far it is obvious that the hotter incubator produces much fewer hatchlings, suggesting that the heat on beaches like North East Bay is the main cause of lower hatching success. As we expected though, the eggs of some turtles do much better at hotter temperatures than others; some turtle’s eggs hatch out completely in the hotter incubators while those of other turtles all die. We think this is because of the amounts of certain nutrients that they are putting into their eggs, and this will be worked out using some biochemical tests on eggs done in the UK later this year. So hopefully we will soon understand better why some turtles on Ascension can nest more successfully than others!

Eggs started hatching in the hotter incubators on the 24^th March. First to arrive was LB1.4, “Elby” for short, weighing in at a healthy 22g (see photo). At incubation temperatures over 29ºC the majority of hatchlings are female, so coming from an incubator at 32.5ºC, Elby is certainly a girl.  Unfortunately the other 113 eggs in the nest that she came from were drowned in the high rollers we had in March, so Elby and the others in the incubators had a lucky escape and kept their feet dry. Since then about 70 others have successfully hatched out. Once they hatch we keep them here for about 48 hours to let their shells fully straighten and harden, and then release them into the sea. Survival of hatchlings is not very high, so it has been hard to watch them go; they never call and they never write! But maybe in 20 years time or so, some of the turtles that hatched out in the Conservation Centre will come back to Ascension to lay their own eggs. Good luck Elby!

Sam Weber