Protected Species

PIFSC is actively engaged in research to support the conservation of sea turtles and marine mammals in the Pacific Islands Region. Studies conducted by Center scientists support management actions of NOAA and partner agencies under provisions of the U.S. Endangered Species Act and Marine Mammal Protection Act, including recovery plans and take reduction plans. Center biologists conduct population monitoring and other research on threatened and endangered populations of sea turtles and the endangered Hawaiian monk seal. Other PIFSC researchers monitor and assess populations of cetaceans across the Region, in collaboration with the Southwest Fisheries Science Center. During 2010, progress was noted in several areas:

NOAA Ship Surveys Support Assessment and Monitoring of Cetaceans in the Central and Western Pacific

High-powered binoculars are used to sight cetaceans at the sea surface.
High-powered binoculars are used to sight cetaceans at the sea surface.
Fraser's dolphins in the Hawaiian Archipelago.
Fraser's dolphins in the Hawaiian Archipelago.
False killer whales.
False killer whales.

Soon after the Center was established by NOAA in 2004, we developed a research program to expand knowledge of cetaceans in the newly created Pacific Islands Region. The program has broad scope, addressing cetaceans in each U.S. Pacific Island area—Hawaii, American Samoa, Guam, Commonwealth of the Northern Mariana Islands, and the Pacific Remote Island Areas—and the adjoining and interconnecting oceanic waters. Current information on cetaceans in this vast region is meager and improved knowledge is essential to support NOAA goals of protected species conservation and ecosystem-based management.

In early 2010, PIFSC scientists conducted visual and acoustic surveys for cetaceans during a 3800-mile transit of the NOAA Ship Oscar Elton Sette between Hawaii and the Mariana Archipelago. While the ship was underway, expedition scientists used high-powered binoculars to scan surrounding waters, looking for whales and dolphins at the sea surface. They sighted 25 groups of cetaceans, including sei whales, sperm whales, false killer whales, melon-headed whales, striped dolphins, and spotted dolphins. To complement the visual survey, the field party used an array of towed hydrophones to detect cetaceans below the sea surface. They frequently heard sounds of minke whales and humpback whales. After arriving in the Marianas, scientists used small boats to conduct visual surveys of cetaceans in nearshore waters around Guam and Saipan, sighting spinner dolphins, sperm whales and pilot whales. During the Sette's return voyage to Honolulu, the research team repeated the visual and acoustic surveys, sighting and hearing the same species found earlier. Analysis of data from the cruise will provide valuable new information on the distribution, abundance, and stock structure of cetaceans across the Hawaii-Marianas survey corridor.

Later in 2010, PIFSC scientists joined with colleagues at the Southwest Fisheries Science Center to conduct the Hawaiian Islands Cetacean and Ecosystem Assessment Survey, a collaborative survey of cetaceans in the 200-nautical mile Exclusive Economic Zone around the Hawaiian Islands, including waters of the Northwestern Hawaiian Islands within the Papahānaumokuākea Marine National Monument. The large-scale expedition involved a pair of NOAA research vessels, the Oscar Elton Sette and the MacArthur II. Operating along parallel, uniformly-spaced oceanic tracklines, the ships covered waters from the Island of Hawaii at the southeast end of the archipelago to Kure Atoll at the northwest end. Scientists aboard the ships used standard visual and acoustic survey methods, collecting data to assess the current abundance of cetacean species in the region. They recorded over 400 cetacean sightings, many accompanied by photographs, and a similar number of acoustic detections. When conditions permitted, they launched small boats to approach cetaceans at the sea surface and used special darts to collect skin biopsy samples for analysis of population genetics and stock structure. Samples from 147 animals representing several cetacean species were collected, including 40 from false killer whales in the offshore and Northwestern Hawaiian Islands portions of the study area. Oceanographic observations collected systematically throughout the survey will help researchers put the cetacean observations into an ecosystem context. Analysis of the cetacean survey data is underway and new abundance estimates should be available for most species by the end of 2011.

Study Expands Knowledge of Loggerhead Turtle Movements and Oceanic Habitat in the East China Sea

For the past decade, scientists at PIFSC have been on the forefront of research to understand the oceanic distribution and habitat of loggerhead sea turtles in a wide area of the North Pacific, particularly in the transition zone north of Hawaii between subtropical and temperate waters. They have equipped live loggerheads with Argos location transmitting tags, released them, and monitored them by polar-orbiting satellites to learn about their movements and dive behavior. And by combining this information with oceanographic data, also collected by satellites, they have learned the preferred pelagic habitats of the turtles and how to predict areas and time periods where fishing vessels are most apt to encounter turtles. This research is fundamental to developing an ecosystem-based strategy for managing pelagic longline fisheries in turtle habitat and reducing turtle mortality caused by interactions with fishing gear.

In 2010, PIFSC scientists and collaborating researchers from Taiwan and Japan reported new results from studies of 34 loggerheads caught incidentally in pound nets moored in shallow water along Taiwan's Pacific coast. Genetic analysis showed that these turtles, like other loggerheads in the North Pacific, were born on nesting beaches on Japan's Pacific coast. The immature turtles were outfitted with satellite transmitting tags and released. The tracking data, downloaded from Argos, documented oceanic journeys from 6 to 503 days.

A Bayesian state-space model was used to process the Argos positional data and estimate the post-release paths of turtles. The turtles mostly occupied the Taiwan Strait and East China Sea. Outside this area, some turtles registered locations in Pacific coastal waters of Taiwan and Japan; others ranged more widely, some venturing northeastward into waters of the Kuroshio Extension Bifurcation Region (KEBR) and adjacent areas of the central North Pacific, others into the Yellow Sea, and a few into coastal waters of Vietnam and Malaysia in the South China Sea. Further analysis of positional data revealed a “hotspot” of high turtle occupancy in the East China Sea; 51% of all track days were recorded there. Bathymetric data showed the hotspot to be a relatively shallow area and chlorophyll-a data indicated that waters there were twice as productive as those encountered by tagged turtles outside the area.

Modeled turtle time tracks were analyzed in conjunction with various oceanographic data, including a new product based on satellite altimetry that resolves mesoscale eddies. In earlier research in the KEBR, PIFSC scientists showed that such eddies are key features of loggerhead foraging habitat. In the present study, the research team found that among eddy features examined, turtles had the highest affinity for eddy edges, but turtles inside the East China Sea high-occupancy area were much less likely to be found near an eddy than those outside the hotspot; even non-sentient objects (like free-drifting buoys and simulated passive particles originating at turtle release sites) showed higher probability of eddy association than the hotspot turtles. This finding is curious, and suggests more research is needed to understand the distribution of eddies in time and space and other factors, such as benthic habitat, that influence the distribution of forage and the behavior of loggerheads in the complex hotspot area.

The tracking data show that loggerheads susceptible to capture in Taiwan's poundnet fishery are apt to visit waters in many national jurisdictions within the Asian region, as well as the high seas, underscoring the critical need for international cooperation in loggerhead conservation. Fishery interactions with loggerheads have been recorded across the range of the turtles, from Asia to North America but rigorously monitored only in the U.S. The East China Sea hotspot is heavily fished, primarily by boats from China.

Tracks of tagged loggerheads determined from Argos satellite data. Circles denote release locations 
                   and stars the last transmitted positions.
Tracks of tagged loggerheads determined from Argos satellite data. Circles denote release locations and stars the last transmitted positions.

New Technology Enables Better Understanding of Foraging Habitat Use by Hawaiian Monk Seals

Between foraging trips, monk seals rest. The GPS-equipped cellular transmitter tag, glued to the 
                   seal's back, transmits data on the animal's location and dive depth, and temperature of the 
                   surrounding water.
Between foraging trips, monk seals rest. The GPS-equipped cellular transmitter tag, glued to the seal's back, transmits data on the animal's location and dive depth, and temperature of the surrounding water.

When they are not ashore resting or nursing their pups, Hawaiian monk seals spend their time at sea searching for something to eat — fish and other marine fauna on the reefs and banks surrounding the islands. Research on foraging habits of monk seals is an important part of the Center's work to support recovery of this endangered species. In parts of the seal's range, persistent declines in seal abundance are caused by high mortality, particularly in juveniles, as a result of chronic food limitation and other factors. Understanding the feeding habits and preferences of the seals, and the abundance of prey species and forage competitors, will help NOAA develop effective recovery strategies.

In the remote Northwestern Hawaiian Islands, where most monk seals live and where the overall seal population is declining at a rate of 4.5% per year, foraging habits have been studied by placing dive recorders, satellite transmitters and cameras (CRITTERCAMS) on seals and analyzing data and video documenting their feeding excursions. Other diet studies have involved analysis of seal scat, spews and blubber.

In the main Hawaiian Islands, where monk seals are increasing in number, a new technology is providing useful information about seal foraging. PIFSC scientists are using telemetry tags featuring a GPS unit, cellular transmitters, and sensors that measure depth and temperature of the water where the seal is swimming. The cell phone transmits the seal's location and environmental data to a computer onshore where scientists can monitor the seal's movements and surroundings at a resolution never before possible.

In 2010, Center researchers put cell phone tags on the backs of 11 older monk seals, gluing the device to their pelage. Data collected so far show that most of the seals made regular trips to sea to forage near shore in a range of habitats from shallow coral reefs to waters over 500 m below the surface. Foraging excursions usually lasted less than 2 days. But one adult male seal tagged on Oahu made an unusually long oceanic voyage lasting for a month, covering 2000 nautical miles.

A GPS-equipped satellite cell phone tag was attached to an adult male Hawaiian monk seal on Oahu. 
                   From March through July 2010, the tag recorded the seal's foraging movements, including a visit to 
                   neighboring Kauai and oceanic waters far offshore.
A GPS-equipped satellite cell phone tag was attached to an adult male Hawaiian monk seal on Oahu. From March through July 2010, the tag recorded the seal's foraging movements, including a visit to neighboring Kauai and oceanic waters far offshore.