Ferocious, pack-feeding jumbo squid have invaded waters off California's central coast and are devouring local fish populations. Researchers say global warming and overfishing are likely to blame.
Humboldt or jumbo squid (Dosidicus gigas) first appeared off Monterey, California during an El Niño event which warmed waters in 1997. Since 2002 they have taken up permanent residence.
The findings offer a striking look at how multiple human-induced environmental changes are affecting ocean ecosystems.
"I think we're seeing the combined results of climate change and overfishing," says Bruce Robison of the Monterey Bay Aquarium Research Institute in California, US. "There has been a big change in the cast of characters out there that may be very significant commercially as well as ecologically."