Our ATV rider called from the Ocean Sands section of Corolla to report turtle crawl. When KC looked at the photos, she declared, “There must be eggs with a body pit that big!”
So the team got to work taking measurements and reading the site. It was a challenge because mom crawled right back over the nest site on her way out. The team did great though locating eggs and before long, they were preparing to place the temperature data logger inside the egg chamber.
While making a place for the data logger, they discovered a “snowman” spacer egg. Spacer eggs are thought to provide additional air pockets to promote air flow in the egg chamber.
As with all of our nest laid here on the OBX we want and hope that all of our nest have great hatching success and most certainly do, but this nest unfortunately did not have any hatching success at all. However, our NCWRC Biologist and NEST volunteers were able to benefit from this nest still by learning a great amount about sea turtle development. After excavating this nest by counting a total of 120 “whole” eggs still in the egg chamber and opening up some of the eggs to record what life stages the turtle eggs were at, it was confirmed that this nest had stopped developing completely at a certain point and was never going to fully develop. Now, your probably thinking how does this happen? Why didn’t all these eggs develop and wasn’t there anything we could do? Unfortunately in this case mother nature was the culprit and there was nothing we could do to stop her but we believe we know how it all happened. The nest was laid on June 29th and all was well until we had a storm surge come through which caused several over washes over the nest including water that pooled and sat over the nesting area for long periods of time. It is common for us to see nests get over wash due to high tides and storms which does not affect development in a nest as much as long as the water is not constantly staying or pooling over the nesting site. When this pooling happens over a nesting site it causes low oxygen levels in the egg chamber which in turn can stop the development of these sea turtle hatchlings. A nest laid about a week before this nest had emergence at 62 days and a nest also laid 4 days after this nest had emergence at 52 days so from these nest, NCWRC Biologist could assume that this nest would have had emergence around day 55 or 56.
Comparing the developmental features with hatchlings that emerged at Day 55 by referencing the scientific article by Fernado Crastz called Embryological stages of the marine turtle these stage 2 hatchlings had vertebral process that could be seen (develops at Day 20), the carapace was evident but not defined at the neck (typical for Day 21), flipper bones could be seen through the skin (typically visible at Day 21) and one hatchling had a slight amount of pigmentation (starts Day 23) while one did not (see photo below). So from these observations and research it seemed that one embryo very likely made it to Day 21 and the other to Day 23 meaning most of the hatchlings likely stopped development around 21 to 23 days assuming they were on track for a day 55 emergence. Looking back at the date when pooling was observed on this nest site which was on July 19th, it was determined that this happened when the nest had been incubating for 20 days which gives us the clarification that this event caused the nest to be unsuccessful. While this is still a sad ending, this nest will help NCWRC Biologist with other nest when there are “stage 2” embryos to try to age. A BIG THANK YOU to the nest parents and nest sitting volunteers who helped on this nest!
- nest number: 06
- town: Corolla
- date eggs laid: 06/29/2017
- begin monitoring: 08/22/2017
- actual emergence date: N/A
- total eggs: 120
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