Overfishing threatens seabird populations worldwide

Science Daily reports on a new major international study of bird populations that has shown that irrespective of breed or location, all seabird populations suffer once fish stocks fall below a critical level.

The study, “Global Seabird Response to Forage Fish Depletion--One-Third for the Birds", examined 14 species of coastal birds across the globe that feed mainly on sardines, anchovies, herring and prawns. Gannets, terns, puffins, seagulls or penguins,  irrespective of species, the study found that if fish stocks fell below a third of their potential maximum, reproduction rates plummeted.

Based on almost 450 years of cumulative observations, the study, is the first to produce hard evidence that, long term, ecosystems obey similar laws. It also provides a good barometer for monitoring the health of marine eco-systems. It demonstrates that overfishing  will cause a collapse of bird populations and that a third of possible maximum populations represents a clear limit to fish stock depletion.

* Bird and Humans both consume around 80 million tons of fish a year so are in direct competition for fish stocks. Predators are vital to the good health of eco-systems.The prey predator relationship is not fully understood but it's feared that  failure to allow adequate fish stocks for birds could precipitate a collapse of marine eco-systems.

Image: Tim Bastable

Parts of the Mediterranean are a dead sea but Marine Reserves can allow systems to recover

National Geographic Magazine report on research published on 29th February 2012 on the impact of overfishing on the Mediterranean, where some areas of the sea are devoid of all live after possibly centuries of overfishing - stunning photographic contrast between sea floor in the degraded areas and marine parks in Spain and account of the success of marine conservation zones in allowing ecosystems to recover.