The number of Galapagos blue footed boobies is declining according to a study published in the April edition of the journal Avian Conservation and Ecology.
According to the study, conducted between 2010 and 2015 by American biologist David Anderson, the number of booby chicks is declining. The reason? A lack of sardines.
Previous research has shown that when the birds had a diet based exclusively on sardines their reproduction rate was optimal. In contrast, when sardines represent less than half of the booby diet, reproduction slows down.
“We believe that the main factor behind the decline is the lack of the appropriate food, namely sardines,” said Kate Huyvaert, of Colorado State University who worked with Anderson in the study.
Johanna Barry, president of the Galapagos Conservancy organization, which funded the stud, said that the experts are not sure if the sardine shortage is natural or related to human activity. She also said that other factors could be involved in the boobie population decline
Pressure from environmental groups has been growing to restrict the number of tourists allowed on the islands, a move that has been fought by tourism interests. “The impact of human activity definitely plays a role in the health and number of species in the Galapagos,” says British biologist Stewart White. “It is difficult to say the lack of sardines and its effect on the boobies is the result of tourism but we think it plays a role,” he says.
According to White, who is a member of the Galapagos Conservancy, the cruise ships and yachts are the most likely culprits in the reduction of sardine populations. He said discussions are scheduled later this month with government biologists to deal with the problem.