Researchers at the University of British Columbia (UBC) have revealed that the world’s monitored seabird populations have dropped 70 per cent since the 1950s.
Lead author Michelle Paleczny, a UBC master’s student and researcher with the Sea Around Us project, published the findings in the journal PLOS ONE.
The information was compiled from studies of more than 500 seabird populations around the world, representing 19 per cent of the global seabird population.
The scientists found that overall populations had declined by 69.6 per cent, equivalent to a loss of about 230 million birds in 60 years.
“Seabirds are particularly good indicators of the health of marine ecosystems,” says Paleczny. ”When we see this magnitude of seabird decline, we can see there is something wrong with marine ecosystems. It gives us an idea of the overall impact we’re having.”
The dramatic decline is said to be caused by a variety of factors, including overfishing of the fish seabirds rely on for food, entanglement in fishing gear, plastic and oil pollution, introduction of non-native predators to seabird colonies, destruction and changes to seabird habitat, and environmental and ecological changes caused by climate change.
Seabirds tend to travel the world’s oceans foraging for food over their long lifetimes, and return to the same colonies to breed. Colony population numbers therefore provide information to scientists about the health of the oceans.
Albatross were part of the study and showed substantial declines. Paleczny says these birds live so long and range so far that they encounter many dangers in their travels.
A major threat to albatross is getting caught on longline fishing hooks and drowning, a problem that kills hundreds of thousands of seabirds every year.
“Our work demonstrates the strong need for increased seabird conservation effort internationally,” says Paleczny. “Loss of seabirds causes a variety of impacts in coastal and marine ecosystems.”
Seabirds play an important role in those ecosystems. They eat and are eaten by a variety of other marine species. They also transport nutrients in their waste back to the coastal ecosystems in which they breed, helping to fertilise entire food webs.
The study is the first to estimate overall change in available global seabird population data and is a collaboration between UBC researchers Paleczny, Vasiliki Karpouzi and Daniel Pauly and Edd Hammill, a lecturer at the University of Technology, Sydney in Australia.
Thanks for the depressing news, Steph.
It's not just overfishing, just climate change destroying the food birds depend upon (like the Murrie die off in Alaska). Vast numbers of birds are also killed by eating plastic.
... 90% of seabirds living today have ingested some form of plastic, mistaking it for fish. Since this material is not able to pass through the animal, these birds are likely to die as a result. The scientists’ data also showed that in 1960, fewer than 5% of birds would have eaten plastic.