Many approaches to preserving the earth's biodiversity focus on so-called hotspots, areas that house a high number of species. These locations have been identified on land around the world, from rainforests in central Chile to the Guinean Forests of West Africa. New research published online this week by the Proceedings of the National Academy of Sciences indicates that the ocean has a similar system of biodiversity richness for its large predators, such as tunas, sharks and sea turtles. The findings could improve the success rate of efforts to conserve threatened marine creatures.

Marine animals tend to be more peripatetic than landlubbers are so it was unclear whether a wide variety of large species would congregate together in a single area. Although scientists suspected certain regions would be richer in species than others, their concentrations had not been quantified. Boris Worm of the Institute for Marine Science in Kiel, Germany and his colleagues analyzed logbook records and information collected by independent observers to track species abundance in the world's oceans. They found that large oceanic predators congregate in hotspots, particularly in intermediate latitudes between 20 and 30 degrees North and South where both temperate and tropical species can thrive. In addition, the variety of habitat and abundance of nutrients that accompany features such as reefs, islands and underwater mountains support the majority of hotspots. The results build on the findings published last year that showed 34 percent of the world's small marine creatures that have restricted ranges can be found in just 0.012 percent of the ocean's total area, making these areas ideal candidates to garner protected status.

Worm and his colleagues also used a computer model to investigate the potential effects of instituting no-fishing zones that coincide with the newfound hotspots. Because the areas have a high number of species, but lower numbers of each type of animal, they are ideal candidates for fishing bans that could safequard threatened creatures while not greatly impacting the overall catch, the researchers suggest. They conclude that "the seemingly monotonous landscape of the open ocean shows rich structure in species diversity and that these features should be used to focus future conservation efforts."