post

Protected Species – Pacific Pelagics

Protected Species and Pelagic Fisheries/Ecosystems

Protected species listed under the Endangered Species Act and known to occur in pelagic waters of the Western Pacific region include green, hawksbill, leatherback, loggerhead and olive ridley sea turtles, humpback, sei, sperm,blue, and fin whales, Hawaiian monk seals , short-tailed albatrosses and Newell’s shearwaters. Other marine mammals known to occur include several types of dolphins and whales, other seabirds known to occur include other albatrosses, shearwaters, petrels, boobies, tropicbirds and other species.

Green Sea Turtles (Chelonia mydas)

green turtleGreen sea turtles are a circumglobal and highly migratory species, nesting and feeding in tropical/subtropical regions. Their range can be defined by a general preference for water temperature above 20° C. Green sea turtles are known to live in pelagic habitats as posthatchlings/juveniles, feeding at or near the ocean surface.

The non-breeding range of this species can lead a pelagic existence many miles from shore while the breeding population lives primarily in bays and estuaries, and are rarely found in the open ocean. Most migration from rookeries to feeding grounds is via coastal waters, with females migrating to breed only once every two years or more. In the Pacific, the only major (> 2,000 nesting females) populations of green turtles occur in Australia and Malaysia. Smaller colonies occur in the insular Pacific islands of Polynesia, Micronesia, and Melanesia and in the Northwestern Hawaiian Islands.

Since the establishment of the ESA in 1973, and following years of exploitation, the nesting population of Hawaiian green turtles has shown a gradual but definite increase and scientists have concluded that this population is well on the way to recovery following 25 years of protection. This increase is attributed to increased female survivorship since the harvesting of turtles was prohibited in addition to the cessation of habitat damage at the nesting beaches since the early 1950s.

Hawksbill Sea Turtles (Eretmochelys imbricata) 

As a hawksbill turtle grows from a juvenile to an adult it switches foraging behaviors from pelagic surface feeding to benthic reef feeding. The maturing turtle establishes foraging territory and will remain in this territory until it is displaced. As with other sea turtles, hawksbills will make long reproductive migrations between foraging and nesting areas but otherwise they remain within coastal reef habitats. Along the far western and southeastern Pacific, hawksbill turtles nest on the islands and mainland of southeast Asia, from China to Japan, and throughout the Philippines, Malaysia, Indonesia, Papua New Guinea, the Solomon Islands, and Australia.

Leatherback Sea Turtles (Dermochelys coriacea) 

Leatherback turtles lead a completely pelagic existence, foraging widely in temperate waters, except during the nesting season when gravid females return to tropical beaches to lay eggs. Males are rarely observed near nesting areas, and it has been proposed that mating most likely takes place outside of tropical waters, before females move to their nesting beaches. Leatherbacks are highly migratory, exploiting convergence zones and upwelling areas in the open ocean, along continental margins, and in archipelagic waters. In a single year, a leatherback may swim more than 10,000 kilometers. Migratory routes of leatherback turtles originating from eastern and western Pacific nesting beaches are not entirely known. However, satellite tracking of postnesting females and genetic analyses of leatherback turtles caught in U.S. Pacific fisheries or stranded on the west coast of the U.S. presents some strong insights into at least a portion of their routes and the importance of particular foraging areas. Current data from genetic research suggest that Pacific leatherback stock structure may vary by region. Due to the fact that leatherback turtles are highly migratory and that stocks mix in high-seas foraging areas, and based on genetic analyses of samples collected by both Hawaii-based and west-coast-based longline observers, leatherback turtles inhabiting the northern and central Pacific Ocean comprise individuals originating from nesting assemblages located south of the equator in the western Pacific (e.g. Indonesia, Solomon Islands) and in the eastern Pacific along the Americas (e.g. Mexico, Costa Rica).

Recent information on leatherbacks tagged off the west coast of the United States has also revealed an important migratory corridor from central California to south of the Hawaiian Islands, leading to western Pacific nesting beaches. Leatherback turtles originating from western Pacific beaches have also been found along the U.S. mainland. There, leatherback turtles have been sighted and reported stranded as far north as Alaska (60° N) and as far south as San Diego, California. Of the stranded leatherback turtles that have been sampled to date from the U.S. mainland, all have been of western Pacific nesting stock origin.

Loggerhead Sea Turtles (Caretta caretta) 

For their first years of life, loggerheads forage in open-ocean pelagic habitats. Both juvenile and subadult loggerheads feed on pelagic crustaceans, mollusks, fish, and algae. Loggerheads are opportunistic feeders that target items floating at or near the surface, and if high densities of prey are present, they will actively forage at depth. As they age, loggerheads begin to move into shallower waters, where, as adults, they forage over a variety of benthic hard- and soft-bottom habitats. In the North Pacific subadults and adults are found in nearshore benthic habitats around southern Japan, as well as in the East China Sea and the South China Sea (e.g. Philippines, Taiwan, Vietnam).In the South Pacific, loggerheads are known to nest in Queensland, Australia.

Olive Ridley Sea Turtles (Lepidochelys olivacea) 

Olive ridleys lead a highly pelagic existence. These sea turtles appear to forage throughout the eastern tropical Pacific Ocean, often in large groups, or flotillas. While olive ridleys generally have a tropical range, individuals do occasionally venture north, some as far as the Gulf of Alaska. The postnesting migration routes of olive ridleys, tracked via satellite from Costa Rica, traversed thousands of kilometers of deep oceanic waters ranging from Mexico to Peru and more than 3,000 kilometers out into the central Pacific.

Humpback Whales (Megaptera novaeangliae) 

Humpback whales winter in shallow nearshore waters of usually 100 fathoms or less. Mature females are believed to conceive on the breeding grounds one winter and give birth the following winter. Within the U.S. EEZ in the North Pacific, there are at least three relatively separate populations of humpback whales that migrate between their respective summer/fall feeding areas to winter/spring calving and mating areas. The Central North Pacific stock of humpback whales winters in the waters of the Main Hawaiian Islands. This population is estimated to total 6,000 – 10,000 individuals and researchers estimate that it is increasing by seven percent per year, putting the species on a track to double in just over a decade. In addition at least six well-defined breeding stocks of humpback whales occur in the Southern Hemisphere.

Sei Whales (Balaenoptera borealis) 

Sei whales have a worldwide distribution but are found mainly in cold temperate to subpolar latitudes rather than in the tropics or near the poles. They are distributed far out to sea and do not appear to be associated with coastal features. The International Whaling Commission only considers one stock of sei whales in the North Pacific, but some evidence exists for multiple populations. In the southern Pacific most observations have been south of 30.

Sperm Whales (Physeter macrocephalus)

Sperm whales are found in tropical to polar waters throughout the world and are among the most abundant large cetaceans in the region. Sperm whales have been sighted around several of the Northwestern Hawaiian Islands and off the main islands of Hawaii. Sightings of sperm whales were made during the 1980s around Guam, and in strandings have been reported on Guam Sperm whales have also been observed around Samoa.

Blue Whales (Balaenoptera musculus) 

Blue whales occur in all oceans, usually along continental shelves, but they can also be found in the shallow inshore waters and on the high seas. The stock structure of blue whales is uncertain.

Fin Whales (Balaenoptera physalus) 

Fin whales are found throughout all oceans and seas of the world from tropical to polar latitudes. Although it is generally believed that fin whales make poleward feeding migrations in summer and move toward the equator in winter, few actual observations of fin whales in tropical and subtropical waters have been documented, particularly in the Pacific Ocean away from continental coasts.

Hawaiian Monk Seals (Monachus schauinslandi)

The Hawaiian monk seal is a tropical seal endemic to the Hawaiian Islands. Today, the entire population of Hawaiian monk seals is about 1,300 to 1,400 and occurs mainly in the NWHI Small populations at Necker Island and Nihoa Island are maintained by both reproduction and immigration, and an increasing number of seals are distributed throughout the MHI where they are also reproducing. 11The 2004 U.S. Pacific Marine Mammal Stock Assessment estimates that there are 1,304 monk seals in the Hawaiian Islands, with at least 52 of those occurring in the Main Hawaiian Islands. There was an exceptional reporting of a pupping at Johnston Atoll in 1969; however, site visits by biologists have been infrequent and it is not known how regularly monk seals use the atoll. Aggressive male monk seals in the NWHI are known to mob females and sometimes kill pups. Mobbing behavior is thought to occur due to a skewed sex ratio, and 22 subadult males were translocated from Laysan Island in the NWHI to the Big Island in the MHI in 1994. In 1998, two males were identified as aggressive at French Frigate Shoals. They were translocated to Johnston Atoll in 1999 and were resighted at that location for a few months, although they have not been resighted recently. At one time it was believed that NWHI lobsters were an important part of the diet of monk seals and this concern may have contributed to the closure of the NWHI lobster fishery. However an ongoing analysis by NMFS of fatty acid signatures in monk seal blubber indicates that lobster and crustaceans in general don’t appear to be very important to monk seals as there are species of NWHI lobsters in relatively high abundance but monk seals are not eating them.

Other Marine Mammals 

Non-ESA Listed Marine Mammals

Common Name

Scientific Name

Common Name

Scientific Name

Blainsville beaked whale

Mesoplodon densirostris

pygmy sperm whale

Kogia breviceps

bottlenose dolphin

Tursiops truncatus

Risso’s dolphin

Grampus griseus

Bryde’s whale

Balaenoptera edeni

rough-toothed dolphin

Steno bredanensis

Cuvier’s beaked whale

Ziphius cavirostris

short-finned pilot whale

Globicephala macrorhynchus

dwarf sperm whale

Kogia simus

spinner dolphin

Stenella longirostris

false killer whale

Pseudorca crassidens

spotted dolphin

Stenella attenuata

killer whale

Orcinus orca

striped dolphin

Stenella coeruleoalba

melon-headed whale

Peponocephala electra

Pacific white-sided dolphin

Lagenorhynchus obliquidens

pygmy killer whale

Feresa attenuata

minke whale

Balaenoptera acutorostrata

Fraser’s dolphin

Lagenodelphis hosei

Dall’s porpoise

Phocoenoides dalli

Longman’s beaked whale

Indopacetus pacificus

Short-tailed albatrosses (Phoebastria immutabilis) 

The short-tailed albatross is the largest seabird in the North Pacific, with a wingspan of more than 3 albatrossesmeters (9 ft) in length. The short-tailed albatross is known to breed only in the western North Pacific Ocean, south of the main islands of Japan. Although at one time there may have been more than ten breeding locations, today there are only two known active breeding colonies: Minami Tori Shima Island and Minami-Kojima Island. On December 14, 2000, one short-tailed albatross was discovered incubating an egg on Yomejima Island of the Ogasawara Islands (southernmost island among the Mukojima Islands). A few short-tailed albatrosses have also been observed attempting to breed, although unsuccessfully, at Midway Atoll in the NWHI. The 2008 worldwide population is estimate at 2,771 individuals and based on breeding pair counts, appears to be increasing by seven percent annually.

Newell’s Shearwater (Puffinus auricularis newelli) 

Generally, the at-sea distribution of the Newell’s shearwater is restricted to the waters surrounding the Hawaii Archipelago, with preference given to the area east and south of the main Hawaiian Islands. The Newell’s shearwater breeds only in colonies on the main Hawaiian Islands where it is threatened by urban development and introduced predators like rats, cats, dogs, and mongooses. Newell’s shearwaters are known to occasionally visit the CNMI. Shearwaters are most active in the day and skim the ocean surface while foraging. During the breeding season, shearwaters tend to forage within 50–62 miles (80–100 km) of their nesting burrows. Shearwaters also tend to be gregarious at sea, and the Newell’s shearwater is known to occasionally follow ships.

Other Seabirds 

Other seabirds found in the region include the black-footed albatross (Phoebastria nigripes), Laysan albatross (Phoebastria immutabilis), masked booby (Sula dactylatra), brown booby (Sula leucogaster), red-footed booby (Sula sula), wedge-tailed shearwater (Puffinus pacificus), Christmas shearwater (Puffinus nativitatis), petrels (Pseudobulweria spp., Pterodroma spp.), tropicbirds (Phaethon spp.), frigatebirds (Fregata spp.), and noddies (Anous spp.). The world’s largest Laysan albatross colony is located on Hawaii’s Midway Atoll where lead paint is reported to be flaking off of deteriorating buildings. Paint chips are consumed by albatross chicks as they wait for their parents to return with food and the American Bird Conservancy has stated that these chicks have shockingly high lead concentrations. The organization estimates that 10,000 chicks die each year as a result. The USFWS has stated that they plan to clean up as many buildings as possible over the next two to four years and will also excavate chip-contaminated soil from around the buildings and six inches down. The soil will be replaced with clean beach sand.

Following consultations under section 7 of the ESA, NMFS has determined that the Pacific pelagic fisheries of the Western Pacific Region are not likely to adversely affect any ESA-listed species or critical habitat.

NMFS has also concluded that the commercial Pacific pelagic fisheries of the Western Pacific region will not affect marine mammals in any manner not considered or authorized under the Marine Mammal Protection Act.