Monk Seals and Sea Turtles on Deserted Islands: NOAA's 2018 Field Season

A rare sight on Laysan Island: a five-year-old monk seal mother with her pup. (Photo: NOAA Fisheries)

On April 15, 2018, NOAA Ship Oscar Elton Sette sailed from Honolulu for the Northwestern Hawaiian Islands to support the recovery of two endangered species, the Hawaiian monk seal and the green sea turtle. It dropped field biologists and their gear at five sites (French Frigate Shoals, Laysan Island, Lisianski Island, Pearl and Hermes Reef and Kure Atoll), where they would spend three to five months counting, tagging and, when needed, rescuing animals on islands in the middle of the Pacific. They sent back notes from the field.

Getting ashore

The first stop, still in the main islands, was Niʻihau and Lehua, surveyed with Niʻihau residents. The Niʻihau teams went on foot, by jeep, on horseback and by helicopter, and counted 40 monk seals. Inside the Papahānaumokuākea Marine National Monument, every soft item a person brings ashore, from clothes to hats and shoes, must be new or used only on that island, so that no seeds or insects hitch a ride. Each island team chooses its wardrobe from a store of quarantine clothes in Honolulu, and the helpers on unloading day make do with what is left, which is why they look, in NOAA's words, a little nutty.

The "keyhole" at Lehua Island on a wet survey day. (Photo: NOAA Fisheries/Mark Sullivan)

Quarantine "field-forward fashion" at Tern Island. (Photo: NOAA Fisheries)

At Tern Island, in French Frigate Shoals, the team fitted two young seals with satellite tags, one of them with a camera as well and the other with a depth recorder, to learn how young seals forage and survive there. The crews carried ashore 250 water jugs and countless five-gallon buckets, enough to live on for three months. On Lisianski, where heavy surf forced the boats to land gear about an eighth of a mile from camp, one biologist's watch counted 10.5 miles of walking to set up four tents. At Pearl and Hermes, an atoll of 194,000 acres with only 80 acres of land on seven shifting islets, the team found five nursing mother-and-pup pairs and only healthy seals. Midway, a naval air station and submarine base in the Second World War, is now a national wildlife refuge where nearly two million birds of 19 species nest, including the world's largest colony of Laysan albatross; there the team counted four nursing and three weaned pups. At Kure, the most remote of the chain and the world's northernmost coral atoll, a single scientist set up camp.

Field camp tents among sooty terns and albatross chicks on Tern Island. (Photo: NOAA Fisheries)

Seals seen from above and from within

A drone team flew 26 flights totaling more than 270 minutes and took over 2,700 photos of seal habitat and more than 100 monk seals, pictures that show each seal's size, age and condition and, in time, will identify individuals by their markings. On the cliffs of Nihoa, about 900 feet high, the drone searched from above in fog while a shore team in the rain marked seals with bleach and flipper tags.

Three monk seals on Mullet Island, from the drone. (Photo: NOAA Fisheries)

"Seal cams" mounted on seals' backs record how they hunt. One young male, Y2JU, made an all-night foraging trip from French Frigate Shoals to Brooks Banks, about 40 miles away. When the team downloaded a recovered camera, they spent an evening watching "seal TV."

From a seal’s camera, recovered at French Frigate Shoals. (Photo: NOAA Fisheries)

Two good-news stories

At Pearl and Hermes, a young female, DH24, developed an abscess about the size of a grapefruit between her shoulder blades. Abscesses can hamper a seal's movement and feeding, and can even burst inside and spread infection through the body. When hers did not drain and began to affect her, the biologists lanced it and gave her antibiotics, and she was later seen healthy.

On Laysan, a five-year-old female had a pup. Five is the youngest age at which monk seals are known to give birth; it had last happened on Laysan 27 years earlier, and there are only seven other such records in the Northwestern Hawaiian Islands.

Turtles

On French Frigate Shoals, the main green turtle nesting beach in the islands, a sea turtle team spends six months tagging every nesting female to estimate how many there are. Researchers measure turtles basking on the beach (a long tail marks a male) and give each one a number, etched into its shell with a tool like a nail-salon drill and painted with non-toxic paint so it stands out. Outside the breeding season, many of these turtles live around the main Hawaiian Islands; NOAA asks anyone who sees a numbered turtle to email respectwildlife@noaa.gov with the number and the location.

Lindsey Bull and Marylou Staman measure a female green turtle on Tern Island. (Photo: NOAA Fisheries)

Jan Willem Staman numbers a green turtle on East Island. (Photo: NOAA Fisheries)

Coming home

Four months on, a later voyage of the Sette collected the camps at Pearl and Hermes, Lisianski and Laysan; French Frigate Shoals stayed until October. Asked what they had missed, the biologists named hot freshwater showers, crisp salads, ice cream, pets, road trips (hard on an island three miles around), fresh fruit and vegetables, beer, since alcohol is not allowed in the monument, and above all family and friends. What kept them going: sunset dinners on the beach, "Blue Planet Tuesdays" with tea and popcorn, crafts, invented holidays such as a "Christmas in July" with carols and presents made from marine debris, and Sunday coffee on the pier with the sharks.

A U.S. Fish and Wildlife Service biologist, David Link, came along to survey birds, invasive plants and ants on each refuge island, and to repeat a 1961 photograph on Laysan that shows how far native replanting has come.

Laysan in 1961. (Photo: U.S. FWS)

The same view in 2018, after native plants were replanted. (Photo: U.S. FWS)

The 2018 monk seal field team aboard the Sette, after their first hot showers, salads and ice cream in months. (Photo: NOAA Fisheries)

Sources

• NOAA Fisheries, "Field Notes: Science and Stewardship in the Northwestern Hawaiian Islands."