MEXICO: Scientists say they have found that some fish can survive in low-oxygen dead zones that are expanding in deep waters off the West Coast as the climate changes.
While the overall number and kinds of fish in those zones are declining, some species appear able to ride it out, according to a study published this month in the journal Fisheries Oceanography.
The study focused on catches from 2008 through 2010 of four species of deepwater groundfish Dover sole, petrale sole, spotted ratfish and greenstriped rockfish.
Catches of ratfish and petrale sole both declined in low-oxygen areas, while catches of greenstriped rockfish and Dover sole showed no changes. Dover sole are well-known for being adapted to low oxygen, but greenstriped rockfish are not.
Oregon State University oceanographer Jack Barth, a co-author, says commercial fishermen will likely start taking oxygen levels into account as they decide where to tow their nets.
“It’s rearranging that ocean geography,” Barth said of the low-oxygen conditions. “If you go out to a spot where you’ve always gone before commercial fishing, and you don’t catch what you expect, is it because the oxygen has gone low and things moved someplace else?”
Dead zones were first noticed off Oregon in 2002, where they peaked in 2006, and have since spread to Washington and California waters.
Some, such as where the Mississippi River flows into the Gulf of Mexico, are caused by agricultural runoff. On the West Coast, scientists have demonstrated they are triggered by climate change.
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