Lindsey Bull and Jan Willem Staman place a purpose-built box around the female green turtle to enable the team to apply a GPS satellite transmitter. Photo: NOAA Fisheries/Camryn Allen.

Michelle and Lindsey proceeded to measure the length of her shell and collect samples for genetic and hormone analysis. They looked for previously applied permanent identification tags that might tell us more about her history, and applied the tag “OA48” to her shell in white non-toxic paint. The team also applied a GPS satellite transmitter to monitor her migration to her nesting ground.

The identifier "OA48" was etched into the turtle's shell, and non-toxic paint was applied. The paint will wear off of the outer shell and remain in the etched markings for easy identification later in the season. Photo: NOAA Fisheries/Michelle Barbieri.

Interestingly, Michelle and Lindsey did discover a permanent identification tag (microchip) on OA48. Searching the microchip number in the database gave them some information about her life history. She was first encountered in 1993, when she was found stuck in a silt pond with leech eggs on her body, leeches in her mouth, and tumors on her right front flipper. At that time, she was in poor condition, so it was great to see her doing so well now.

In 1993, OA48’s shell was 34.9 inches long. Since then, she has grown less than a quarter of an inch in length and less than half an inch in width, suggesting that she was a mature female in 1993. Sea turtles reach sexual maturity in Hawai‘i between 23 and 38 years. OA48 must have been at least 23 years old in 1993, so she is likely at least 49 years old today. That may sound old, but the oldest known nesting female in Hawai‘i is 61.

As they released OA48 and she made her way to the water, the team pondered what they should nickname her. “I like the name Motherload because you said we hit the mother lode at the beginning of the day,” Michelle said. Camryn agreed, “She is loaded with yolked-up follicles, so the name is fitting.”

OA48, nicknamed "Motherload," makes her way back to the water on O‘ahu's North Shore. She is now outfitted with a satellite transmitter. Photo: NOAA Fisheries/Camryn Allen.

Motherload's Journey

Motherload’s satellite tag allowed the team to watch her movements from the Science Center in Honolulu. Camryn was patiently checking on Motherload’s status, and on Thursday, March 28th, she saw something new. She jumped up and ran to the office of Dr. T. Todd Jones—the leader of the Marine Turtle Biology and Assessment Program—announcing, “Motherload left! We did it!”

Motherload departed the North Shore of O‘ahu and had already passed Kaua‘i just 2 weeks after they tagged her. Their timing could hardly have been better.

Camryn taped maps of Motherload’s location to her office door for her colleagues to follow her journey. “She’s ~28 nautical miles away from French Frigate Shoals!” Camryn announced on April 6th.

But only nine days later, Camryn logged in to her computer to find a new development: Motherload had passed French Frigate Shoals. She was about 60 miles southwest of the atoll, apparently continuing west. “The next [known] nesting beach is about 200 miles farther—at Laysan Island,” Camryn said, “so we will have to see what she does over the next few days.” T. Todd explained, “she may tack back to get her bearings.”

Satellite track of OA48, Motherload, showing her southwest of French Frigate Shoals by approximately 60 miles, apparently heading west.

The team waited with bated breath, but not for long—the following day, April 16th, Motherload’s track showed that she had turned, just as T. Todd predicted, and was heading for French Frigate Shoals.

Satellite track showing Motherload turning back towards French Frigate Shoals.

Motherload arrived at French Frigate Shoals on Wednesday, April 17th. Between her departure from O‘ahu and her arrival at the atoll, she swam nearly 620 miles in 2½ weeks.

The satellite track of Motherload's journey of more than 600 miles from O‘ahu to French Frigate Shoals.

Now, staff wait patiently to see what Motherload will do. To fertilize her eggs, she will need a mate. Then, she will lay her eggs in “clutches” every 2 weeks, laying three or four nests.

But where will she lay them?

As of April 25th, Motherload has spent much of her time around Tern Island—a World War II-era runway surrounded in part by the original seawall and building structures. Motherload has also scoped out the prior location of Trig Island, and the team wonders if she will check-in on the Gins and the reformation of East.

Satellite track of Motherload's activity at Tern Island (left side) and the former location of Trig Island (upper right) at French Frigate Shoals in the Northwestern Hawaiian Islands.