Plastic from remote corners of the South Pacific, including nesting areas for New Zealand albatrosses, has confirmed the global threat to seabirds from plastic pollution.
The study, published October 12 in the journal Aquatic Conservation: Marine and Freshwater Ecosystems, examines patterns in plastic seabirds from across the South Pacific.
It uses data that the Canterbury Museum's senior curator of natural history, Dr. Paul Scofield, and ornithologist Christopher Robertson from Wellington in the late 1990s and 2000s.
"Plastic pollution is a major threat to seabird species, not just here in New Zealand but around the world," says Dr. Scofield. “If we know more about how seabirds interact with plastic, we may be able to solve this problem in the future. Right now it's only getting worse. "
Christopher Robertson, co-author of the study, says, “One of the interesting things we got from this study is that it shows you how far plastic can travel in the ocean. Some of the areas where we collected the plastic are very remote. To me this shows that this is a global problem; It is not something that a single country can solve on its own. "
“With the samples provided by our New Zealand colleagues, we were able to study the patterns of interactions between seabirds and plastic across the South Pacific on a larger scale,” says lead author of the study, Valeria Hidalgo-Ruz of the Chilean Millennium Nucleus Center for Ecology and Sustainable Management of the Oceanic Islands.
"The results confirm that even seabirds in one of the most remote areas in the world, the Rapa Nui ecoregion (Easter Island), are severely affected by this global problem, underscoring the need for urgent solutions."
In the late 1990s and 2000s, field workers collected thousands of pieces of plastic from albatross nesting sites on the Chatham Islands, Campbell Island and Taiaroa Head in Otago. The birds swallowed most of the plastic while foraging at sea, and then spat it out at the nesting sites as they tried to feed their chicks.
Between 2003 and 2004, the team also examined plastic from the stomachs of Sooty Shearwaters that were killed by fishing operations around the Chatham Rise and the southeast coast of the South Island.
The study compared these plastics to similar samples from other locations in the Pacific, including the coast of Chile and Rapa Nui. The researchers examined the types of plastic found along with their shape, color and density.
Albatrosses tend to eat colored plastic, especially red, green and blue. The birds are likely to mistake these objects for prey. The study suggests that the colorful fishing gear used in commercial fishing in the Chatham Islands and Chile may be the source of some of the plastic found in these nesting sites.
Plastics in the stomach of diving seabirds like the Sooty Shearwater have been dominated by hard, white / gray, and round plastic objects. The researchers believe that most of these objects are inadvertently picked up when the birds eat fish or other prey that has consumed plastic.
Marine plastic uptake is an important issue for seabird conservation and is estimated to affect most seabird species by 2050.