A team of researchers recently returned to Honolulu with positive news on Hawaiian marine life in the remote Papahanaumokuakea Marine National Monument 1,500 miles northwest of Hawaii.
Hawaiian monk seal pups were born and mostly appeared healthy, while a large population of green sea turtles was seen at Tern Island.
The National Oceanic and Atmospheric Administration’s ship Oscar Elton Sette arrived in Honolulu Tuesday with more than a dozen field biologists who had been conducting research on Hawaiian monk seals and sea turtles at various isles since May.
Field researchers had set up camps at Kure Atoll, Pearl and Hermes Atoll, Lisianski Island, Laysan Island and French Frigate Shoals.
While there, they conducted daily seal surveys, tagged and measured recently weaned pups and disentangled some from nets and other marine debris.
This summer, they counted more than 140 Hawaiian monk seal pups in the Northwestern Hawaiian Islands, which has been the average for the past few seasons.
The team also made a surprise discovery — Hawaiian monk seal mom GV18 appeared to have given birth to twins.
Researchers observed GV18 at Lisianski Island, nursing a pair of pups about the same size. The pups weaned about midway through the season, according to research ecologist Stacie Robinson. They were on the thinner side but appeared healthy.
The team is eagerly awaiting DNA test results to confirm that the pair — a boy and girl — are twins. The birth of Hawaiian multiple monk seal pups is exceptionally rare, and occurs in only 0.1% of all births, according to researchers.
In addition to seal surveys, experts on NWHI research trips also relocate weaned pups to better spots to increase their chances of survival and help seals in need of medical assistance, said Shawn Farry, a biological research associate and field team leader at French Frigate Shoals.
On this trip, the team brought back four malnourished monk seal pups to get care at the Marine Mammal Center’s Ke Kai Ola hospital in Kailua-Kona. Years of data have shown that weaned, underweight pups have a low chance of survival, according to researchers.
The four female pups — two from Pearl and Hermes Reef and two from Lisianski Island — are now undergoing rehabilitation.
Researchers this year were also focused on assessing conditions at French Frigate Shoals, which sustained major damage after Hurricane Walaka passed through in October, wiping out a significant reef and washing away East Island.
Farry, who has been participating in the field camps since 1993, said East Island is now reforming into a much smaller isle. Historically, East Island was one of the largest pupping sites, and monk seals are still pupping there.
A three-person sea turtle field research team also set out for the French Frigate Shoals, where an estimated 96% of Hawaiian green sea turtles migrate to reproduce.
Marylou Staman, research technician with NOAA’s Marine Turtle Biology and Assessment Program, said the team identified and numbered 583 individual green sea turtles this season.
One female turtle, nicknamed Motherload, was outfitted with a satellite tag on Oahu’s North Shore before she left for the Northwestern Hawaiian Islands so researchers could track where she laid eggs.
Motherload, or OA48, laid four large clutches on Tern Island, said Staman, and has already migrated back to her usual foraging grounds off of Oahu’s North Shore.
Since East Island is no longer large enough, the team set up camp on Tern Island, and used small boats to survey turtles on East Island.
The island was large enough to encourage nesting among turtles, said Staman, but king tides washed over parts of the isle, and some eggs were observed washing out of the berm.
The turtles identified in the NWHI are likely now swimming around the main Hawaiian isles, and the research team is inviting the public to help track them by the letter-and-number combinations painted in nontoxic white paint on their shells.
At the same time, researchers remind the public to keep a respectful distance from wildlife. Hawaiian monk seals are a critically endangered species, with only about 1,400 remaining in the wild. Hawaiian green sea turtles are classified as threatened.
Through the camps, researchers have been able to compile some of the longest-running datasets for species conservation. It was the 38th field season for Hawaiian monk seals, and the 47th field season for Hawaiian green sea turtles.