Loggerhead and Green Sea Turtle Night Research: New Nesting Record and Leatherback Update

We begin with big news out of Juno Beach: We have officially broken the all time record for nests in a single season!!!! As of Saturday, August 3rd, we have recorded 19,198 total nests on our 9.5 miles of beaches, which beats the previous record set in 2017 of 19,085!! And with a few months remaining in the 2019 nesting season, this record is surely to grow as the Research Department continues patrolling the beaches from Tequesta to Juno until the last nest has been excavated!

Appropriately named Biggie, this loggerhead has one of the largest heads and carapace lengths (108 cm/3.5 ft) we have encountered this season! (Photo: Derek Aoki)

Week 7 closes our work with loggerheads at night, as their nesting numbers are begging to taper off. But we were able to get a couple final ultrasound images and blood samples for the metabolomics and endarteritis studies as we bid farewell to these big headed creatures for the season. However, green turtles are still nesting at a relatively high rate, so we will continue to sample them until our target number is reached.

Data Manager Sarah Hirsch takes an ultrasound image of Snooooop, while Director of Research Justin Perrault collects blood. (Photo: Derek Aoki)
Athena, a green turtle, commences to front flipper cover her clutch, meaning she will throw sand from with her large front flippers behind her in order to disguise her nest. (Photo: Derek Aoki)

As the calendar turns to August, the leatherback nests we marked between April to June have mostly hatched or reached their last day of viability. Our morning crew will excavate, or dig up, a nest three days after it hatches or when it reaches its 80th incubation day (70th day for greens and loggerheads) in order to see how many egg hatched, are unhatched, if there are any live or dead hatchlings still in the chamber, and then take a some measurements to see how big her egg chamber is.

Currently, our leatherbacks have a hatch success rate of 53%, which is consistent with their historical average of 50-60%. This is determined by dividing the number of hatched eggs by the total number of viable in the clutch. Leatherbacks lay spacer, or yolk-less, eggs, which are smaller than their ‘normal’ eggs and will not produce an embryo. Therefore these eggs do not count towards the hatch success rate.

Nerita, a 178.7 cm CCL leatherback, finishes laying her only nest that our night crew encountered. (Photo: Derek Aoki)

Nerita, first tagged in 2005, was the largest of the 95 mamas we sampled and was only seen once by our night crew. Having a curved carapace length of 178.8 cm (5.9 ft), she had a fairly successful hatchout rate of 65.52%, in which she deposited 58 eggs and 22 spacers, of which 38 hatched.

Juno, a 161 cm (5.3 ft) CCL mama, seen laying her first of three nests our Night Crew witnessed. (Photo: Derek Aoki)

Juno, originally tagged in 2001, was one of the oldest turtles we sampled and we caught her three times this season! Her first nest was very successful, having a hatch rate of 83.75% (67 hatched out of 80 eggs and 5 spacers). Her second nest came in at 44.74% (51 hatched of 114 viable eggs and 5 spacers), and her third nest had a hatch rate of 42.47% (31 hatched of 73 total eggs with 21 spacers).

Our first and only encounter with Tricia, seen covering her nest at the beginning of the leatherback nesting season. (Photo: Derek Aoki)

A new comer this season, Tricia was first tagged early on in the 2019 season and we only saw her that one time. She had a 33.85% hatch rate that comprised of 22 hatched eggs out of a total of 65 eggs with 8 spacers.

That is all for this week! Come back next week as we continue to wind down the 2019 season of night surveys and add to our record breaking season!

Disclaimer: All marine turtle images taken in Florida were obtained with the approval of the U.S. Fish & Wildlife Service (USFWS) and the Florida Fish & Wildlife Conservation Commission (FWC) under conditions not harmful to this or other turtles. Images were acquired while conducting authorized research activities pursuant to FWC MTP-19-205.