There are at least 350 species of seabirds in the world today. Some of them are daring navigators, like the albatross, ranging far from land in search for food. Others, like the Emperor penguin, are the only birds to breed during the harsh winters of Antarctica.
Shorebirds or ocean-going navigators, seabirds all have one thing in common. They depend on the oceans of the world for sustenance. Seabirds are also a great indicator of the health of the whole marine ecosystem, not only the open ocean, but the shoreline as well.
Conservationists have known for a long time about the decline in seabird populations, says the Guardian. But a new study in PLOS One suggests that overfishing and pollution have led to a 69.9 percent decline in populations, far worse than previously thought.
Lead author, Michelle Paleczny with the University of British Columbia and the Sea Around Us Project, says, “Seabirds are particularly good indicators of the health of marine ecosystems. 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 study determined there were a number of factors that have led to the decline, including overfishing of the fish seabirds feed on, entanglement in fishing nets and lines, oil and plastics pollution, predators feeding on their eggs, and destruction and changes to their habitat. Environmental and ecological changes due to climate change are also factors.
Seabird populations have been well-documented. The researchers used accumulated data (1950- 2010) to compile information on more than 500 seabird populations around the world, representing 19 percent of the global seabird population. The biggest drops in seabird populations were seen in the Southern Hemisphere, which includes Australia, Antarctica, most of South America and a third of Africa.
One of the hardest hit families the Sternidea, which includes terns, saw a decline of 85.8 percent. The Frigatidae, a family that includes frigatebirds, saw declines of 81.7 percent. The Phalacrocoracida, which include cormorants and shags, declined 73.6 percent, according to CBS News.
The research also showed some populations actually increased, a sign that conservation efforts are working in some places. There have been successful efforts to rid some Pacific islands of rats, cats and other invasive species, and in another successful project, the conservation group, Birdlife, worked with fishermen in South Africa to reduce bycatch by 99 percent.
There are solutions to many of the threats. The study suggests: “Increased efforts should be made to rid seabird colonies of invasive species, reduce bycatch in fisheries or the ensnaring of birds in fishnets, and setting up conservation areas.”
The biggest problem is, of course, plastics in the ocean. A study released last month stated that 90 percent of the world’s seabirds have plastic in their intestines. “I have seen everything from cigarette lighters…to bottle caps to model cars. I’ve found toys [inside seabird guts],” co-author Denise Hardesty, with CSIRO, told the Associated Press, and as reported by the Guardian.
The study, “Population Trend of the World’s Monitored Seabirds, 1950-2010,” was published in the journal PLOS One on June 9, 2015.
