In the last six years, California has seen a major increase in the number of jumbo squid off the coast. Though there are several competing theories as to why this invasion has occurred, scientists say jumbo squid can be considered to be one of the "early winners" of ocean climate change.

It is the swelling biomass of lanternfish that explains the squid’s presence, the scientists say. Lanternfish comprise more than 400 species and are far more abundant than sardines or anchovies. Little is known about them, however, because they are not commercially exploited.

Others on the climate change 'win list' potentially include sperm whales, a jumbo squid predator whose numbers appear to have doubled off the West Coast in the last 15 years, said NOAA Fisheries biologist John Field, a collaborator on the project, who recently organised a CalCOFI symposium on jumbo squid.

In the absence of fishing pressure, some sharks could also be on the win list. In fact, it is believed that overfishing of sharks, and to a lesser extent tunas, both of which normally keep the squid’s numbers in check, has probably contributed to the jumbo squid’s population boom.

A major goal of the project is to estimate the squid’s biomass in the California Current, which stretches along the entire U.S. West Coast, and to document the squid’s feeding behaviour – to provide managers with ball-park numbers of the squid’s impact on species of management concern such as hake, market squid and rockfishes.

“We have no direct evidence the squid is impacting fisheries,” Field said. But, it is reasonable to assume they could – or are. Adult jumbo squid off California can weigh 30 kilos. The animals reach this super-size in about a year.

“You have a new predator on the block that is pretty awesome,” Stanford biologist William Gilly, who has funding from the California Ocean Protection Council and California Sea Grant to study the squid’s influence on the California Current ecosystem, said. “They have huge energy requirements and they are starting to eat things that people care about.”

NOAA’s California Sea Grant is a statewide, multi-university programme of marine research, extension services and education activities.

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