Artifical Breeding Colonies Proposed for Endanagered Albatross
ANCHORAGE, Alaska, October 28, 2005 (ENS) - To ensure a future for the endangered short-tailed albatross, a team selected by the U.S. Fish and Wildlife Service has advised the agency to establish one or more new breeding colonies of the seabirds. Threatened by volcanic eruptions, mudslides, drowning in fishing nets and ingestion of plastics, the once abundant species now numbers just 2,000 birds.
The short-tailed albatross, Phoebastria albatrus, the largest of the three North Pacific albatross species, is federally listed as endangered, and once numbered in the millions and was the most abundant albatross species in the North Pacific biologists believe.
Millions of these birds were taken by feather hunters before and after the turn of the 20th century, resulting in the near-extirpation of the species, the Service says. Numbers were reduced to as few as 40 or 50 birds in 1940. Today, about 2,000 short-tailed albatrosses remain, up from about 1,500 five years ago.
These birds are known to breed only on two remote islands in the western Pacific. Torishima Island, Japan, where the majority of short-tailed albatrosses breed, is an active volcano.
The total cost of recovery is estimated at US$5.67 million over 25 years, and the cost to establish the new breeding colonies is estimated at a little more than $2 million through the year 2027.
The island of Torishima, where 80 to 85 percent of short-tailed albatrosses breed, is an active volcano, and Tsubame-zaki, the natural colony site on this island, is susceptible to mud slides and erosion.
The primary threat to the species’ recovery is the possibility of an eruption of Torishima. A minor eruption occurred there in August of 2002, after the end of the breeding season.
The main colony site also is vulnerable to damage or destruction from volcanic eruptions, runoff from torrential rain, and typhoon-induced erosion.
The recovery team suggests that the most promising site for new colony establishment is in the Ogasawara group of the Bonin Islands. These islands, located about 1,000 kilometers (600 miles) south of Tokyo and 300 kilometers (200 miles) south of Torishima, belong to the Metropolis of Tokyo.
Japanese researchers made a reconnaissance trip to the Bonin Islands in March. Based on the results of this trip, the most favorable site for establishment of a new colony appears to be on the northwestern part of Mukojima, the recovery team wrote.
The scientists intend to try to induce a new colony to form by using decoys and a sound system playing back recorded vocalizations from the Tsubame-zaki colony. This is the least costly method, but if it fails, the team says physical translocation of the birds may be necessary.
The remainder of known short-tailed albatrosses breed at a site in the Senkaku Islands, to the southwest of Torishima, where volcanism is not a threat, but political uncertainty and the potential for oil development exist.
The Japanese government designated the short-tailed albatross as a Natural Monument in 1958 and as a Special Bird for Protection in 1972.
The advisory team explains in their Draft Recovery Report that short-tailed albatrosses require remote islands for breeding habitat. The birds nest in open, treeless areas with low vegetation or none at all.
Short-tailed albatrosses spend much of their time feeding in shelf-break areas of the Bering Sea, Aleutian chain and in other Alaskan, Japanese and Russian waters, as they require nutrient-rich areas of ocean upwelling for their foraging habitat, the team explains.
The major threat of overexploitation for feathers that led to the species’ original endangered status no longer occurs, but there are many other threats. Incidental catch in commercial fisheries, ingestion of plastics, contamination by oil and other pollutants, the potential for competition with non-native species, and adverse effects related to global climate change all take their toll.
But these secondary threats will not prevent recovery if the population is growing at a steady rate, the team said.
The short-tailed albatross may be considered for delisting when the total breeding population reaches a minimum of 1,000 pairs; and the three year running average growth rate of the population is six percent for seven years.
In addition, at least 250 breeding pairs must exist on at least two non-volcanic islands; and a minimum of 10 percent of these, 25 pairs, occur on a site or sites other than the Senkaku Islands.
In addition, a post-delisting monitoring plan and agreement to continue post-delisting monitoring must be in place and ready for implementation at the time of delisting, the team advised.
The Fish and Wildlife Service says restoring endangered or threatened animals and plants to the point where they are again secure and self-sustaining within their ecosystems is a primary goal of its endangered species program.
The short-tailed albatross draft recovery plan is open for public comment, and comments are due within the next 60 days. A copy of the draft recovery plan is online at: http://endangered.fws.gov/recovery/index.html#plans.
Comments may be sent to: U.S. Fish and Wildlife Service, Anchorage Fish and Wildlife Field Office, 605 W. 4th Avenue, Anchorage, AK 99501. Tel: 907-271-2888.