Manicured turtles swim for science

Scientists tracking the dispersal of hatchling loggerhead turtles have resorted to the nail salon to help fit tiny tags to the endangered creatures.

The Florida team tried several ideas to attach the technology to the animals, which measure less than 20cm in length.

This included making little harnesses, and using tough epoxy adhesives.

But it was only when the turtle shells were prepared like a manicurist primes fingernails that the satellite tags would stay on for a useful period.

“My collaborator typically has very fancy toenails that are nicely manicured with painted waves and other designs on them,” recalls Kate Mansfield, a US National Marine Fisheries Service scientist in Miami.

“We gave her manicurist a call and her manicurist recommended we use an acrylic base coat. We went out to our local pharmacy and picked some up and tried it on the turtles. We prepped the shell, sanded it down a little bit, buffed it nicely – kind of a turtle spa.

“The acrylic base coat extended our attachments by upwards of two to three months.”

The nail trick is a breakthrough in the study of Atlantic loggerheads (Caretta caretta) because scientists have been struggling to find an effective way to study these animals’ early years.

Something like 80% of female loggerheads will nest in Florida. When their hatchlings emerge 40-70 days later, they make a mad dash for the water and swim out into the open ocean.

Researchers have some information on the movements of these neonates from strandings and bycatch, but those first few years in the Atlantic are largely “lost years” to science. It may be up to a decade before these wanderers return to near-shore habitats.

Fitting satellite trackers is the obvious answer, and the latest generation of tags is now small enough not to impede the junior turtles’ natural behaviour.

But the compact solar-powered units, originally developed to study the migration of birds, are expensive and must stay in place long enough to return useful data and justify the investment.

This is complicated by the speed at which the turtles grow. Their weight can increase five-fold in their first three months at sea.

Mansfield and colleagues approached the problem in a number of ways, even making little costumes out of Lycra and neoprene wet suit material to carry the tags.

These were cut to a range of styles. One was referred to as “The Borat” because of its likeness to the “mankini” outfit worn by actor Sacha Baron Cohen in the comedy movie of that name .

The aim was to incorporate a mechanism, such as Velcro, that would allow the tag to drop off after a productive dataset had been acquired.

“We were trying to go in for that Janet Jackson wardrobe-failure moment where the turtles would pop out of their harnesses, but unfortunately we couldn’t quite come up with the right mechanism for the harnesses to be shed over time as the turtles grew,” Dr Mansfield told BBC News.

Direct attachment ideas included using hard epoxy glues.

These were found to be short-lived. The top layer of the keratin shell would peel away as the turtle grew. The epoxy glues also had a tendency to deform the shell.

The team eventually settled on a preparation that involved the base-coat of the manicurist’s acrylic and a mount for the tags of neoprene strips held in place by a silicone-based adhesive.

Laboratory trials showed this combination would keep the tracker locked down for a minimum of 50-plus days. In contrast, hard epoxy preparations would come off after only a couple of weeks.

Dr Mansfield and colleagues are now compiling a report on what they have learnt about neonate dispersal in the open ocean from their manicured turtles.