New York, July 10 (IANS): The world's monitored seabird population has dropped 70 percent since the 1950s, a stark indication that marine ecosystems are not doing well, says a study.

Researchers compiled information of 500 seabird populations from around the world, representing 19 percent of the global seabird population and found that overall population had declined by 69.6 percent, equivalent to a loss of about 230 million birds in 60 years.

"Seabirds are particularly good indicators of the health of marine ecosystems," said co-author Michelle Paleczny, University of British Columbia's master's student and one of the researcher.

"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 have," Paleczny said.

The study, published in Plos One, is the first to estimate overall change in available global seabird population data.

Some of the factors leading to such a sramatic decline include: overfishing of the fish seabirds rely on for food, birds getting tangled 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.

"Our work demonstrates the strong need for increased seabird conservation effort internationally."

The loss of seabirds causes a variety of impacts in coastal and marine ecosystems as they eat and are eaten by a many other marine species.

The seabirds also transport nutrients in their waste back to the coastal ecosystems in which they breed, helping to fertilise entire food webs.