Seabirds, such as albatrosses and large petrels, have enormous geographic ranges that often span multiple oceans and national territories. Some of these birds can spend up to a decade at a time at sea, where they feed on fish, squid, and krill. These characteristics also make them highly vulnerable to injury and death from fishing gear—chiefly from diving on baited hooks or entanglement and drowning in nets and lines. In some areas the birds may also suffer from a scarcity of food due to overfishing.
In a new study co-written by 2009 Pew marine fellow Matthieu Le Corre in the journal Science Advances, a team of researchers assembled a dataset composed of tracking information from 39 species of albatrosses and large petrels to investigate how seabirds use ocean habitats throughout their life cycles. The team also produced the first global estimates of how important various areas of the planet are to these species’ survival.
The authors found that the high seas—or areas beyond the jurisdiction of any country—are important to the survival of every species of albatross and large petrel, regardless of its country of origin. All the species included in the study spent time traversing or foraging in high seas habitats each year. The researchers also identified specific high seas areas, such as the north-central Atlantic Ocean and the Southern Ocean south of Tasmania, as hotspots where large numbers of species spend significant amounts of time.
The research also highlighted the importance of areas managed by individual regional fisheries management organizations (RFMOs), which oversee fishing in certain areas of the high seas, to seabird populations.
Important links between countries were also revealed by the team’s analyses of seabird movements. Nearly all the studied species annually visited the territory of a country other than the one in which they hatched. For example, species from New Zealand were found to spend significant time in the waters of Chile, and vice versa. Further, the authors found, some countries, such as Uruguay, Namibia, and Peru, have no breeding populations of albatrosses or large petrels but provide important nonbreeding habitat to 10 or more of the seabird species.
Le Corre, who used his Pew fellowship to study seabirds of the Western Indian Ocean, says that understanding where species forage and migrate at sea is critical to effectively conserving them.
“Seabirds are traveling everywhere at sea, and they are endangered almost everywhere due to fisheries bycatch and competition for food,” he explains. “Not a single country can solve this problem alone, because if you protect seabirds in your country, you might only be protecting 10% of the life span of a given species—so there is a need for a global view of seabird conservation at sea.”
By highlighting connections between countries, and between countries and RFMOs, the scientists hope to inform more effective conservation of albatrosses and large petrels. Many governments are signed on to bilateral and multilateral agreements to protect seabird populations, but the research reveals important gaps in these protections stemming from the birds’ highly migratory behavior. For example, species from Australia and Japan, which are the focus of the Japan-Australia Migratory Bird Agreement, were found to spend significant time in Russian waters.
The team cautioned that, although this research provides valuable insights into the migrations of large seabird species, the work tracked only breeding-age birds. Juveniles can use habitat differently than adult birds do and may be exposed to different threats. Further research could help to identify these differences.
Many of the findings, such as the importance of international cooperation, are relevant for conservation of most other seabirds not included in the study, Le Corre adds.
“If you look at the Barau’s petrel or the Mascarene petrel, for example, two endemic and endangered seabirds of Réunion Island, (Indian Ocean) they will spend their first four to eight years at sea, and they will not touch land until they return for breeding,” he explains. “During this time they are traveling everywhere in the ocean—they cross the high seas, they cross EEZs, and they absolutely don’t care about boundaries—so if our vision of protection is too narrow, we will not manage to effectively conserve our seabirds.”
Polita Glynn is a project director and Nathan Fedrizzi is a principal associate with The Pew Charitable Trusts’ Pew Fellows Program in Marine Conservation.