Hold the anchovies - Magellanic Penguins need them

08-01-2007

Rapid expansion of Argentina’s new anchovy fishery may threaten the world’s largest colony of Near Threatened Magellanic Penguins Spheniscus magellanicus at Punta Tombo, Patagonia. Anchovies make up more than 50 percent of the Magellanic Penguin’s diet.

A paper in Science reveals that the country’s plan to develop a small-scale trawler fishery for the “under-exploited” anchovy includes no mechanism to quantify the impact on wildlife.

The anchovies are turned into fish meal, much of which goes to fish farms in China and Europe. Ten pounds of anchovy may be required to produce one pound of farmed fish. The value of the fishery is a fraction of the ecotourism revenues generated by the penguins and other “charismatic megafauna” which depend on the anchovies and the larger fish that feed on them.

“Rising global demand for fish meal could fuel unsustainable anchovy fishery expansion on the Patagonian coast”, the paper’s authors warn. They say anchovy populations are naturally variable, and long-lived predators like penguins, sea-elephants and sea-lions can ride over the scarce years -“as long as good years follow bad”.

But when bad years follow bad years, populations may be unable to bounce back. Nearly ten years after the severe El Nino of 1997-8, the Humboldt’s Penguin Spheniscus humboldti colony at Punta San Juan, Peru, previously 5000 strong, has reached just 2000 birds. Research into the causes of this failure to recover points to overfishing: Peru’s long-established anchovy fishery takes up to 85 percent of the anchovies in Peru’s waters, and studies by the World Bank and others indicate that the catch needs to be halved to provide a sustainable future for fisherman and wildlife.

“Before any further expansion and investment takes place, the costs to other fisheries, risks to wildlife and ecotourism, and food web interactions need to be determined,” the authors of the Science paper conclude. They add that to make informed decisions about the future management of the fishery, research into ecosystems and indicator species like the penguins is needed.

Overfishing of anchovies in Peru poses a threat to other birds. A recent article in World Birdwatch magazine highlights the threat posed by overfishing to “Guano Birds” like Guanay Cormorants Phalacrocorax bougainvillii, and Peruvian Boobies Sula variegata.

You can download the article, titled 'Peru's marine life losing out to fishfarms', from the September 2006 edition of this award-winning magazine by clicking here.