Fish diversity declines in the deep ocean

There are fewer and fewer species of big fish in the deep sea, putting overall ocean health in danger. Scientists have known for years that overfishing diminishes species diversity in coastal areas, but in a study published today in the journal Science, researchers report a drop in diversity of deep-ocean fish as well — in many areas about 50 percent since the 1950s. For example, in places where the tuna catch used to include several different species, including bluefin and albacore, now mostly yellowjack and skipjack remain. If these two types of tuna cannot withstand environmental challenges like global warming, “we may have very little to fall back on,” says study coauthor Boris Worm. “The oceans have been drained of species, basically.” But there’s a hopeful finding as well: The study has revealed a few key spots where sea life congregates. Worm hopes that like coral reefs or rainforests, these areas will capture the public’s imagination and focus conservation efforts for maximum future impact.