Jumbo squid mystery solved

JULY 18, 2019

by Michelle Horton, Stanford University

The culprit responsible for the decline of Mexico's once lucrative jumbo squid fishery has remained a mystery, until now. A new Stanford-led study published in the ICES Journal of Marine Science identifies shifting weather patterns and ocean conditions as among the reasons for the collapse, which spells trouble for the Gulf of California's marine ecosystems and fishery-dependent economies. It could also be a sign of things to come elsewhere.

"What is happening with the jumbo squid is indicative of larger changes impacting marine organisms and ecosystems across the northeast Pacific," said the study's lead author, Timothy Frawley, who was a Stanford graduate student when he conducted the research. "In many respects these squid, with their unique and adaptive survival strategies, function as sentinels of environmental change." William Gilly, professor of biology, was senior author of the study.

Warmer waters

Also known as the Humboldt squid, these large, predatory creatures are targets of the world's biggest invertebrate fishery, commercially fished in Peru, Chile and Baja California. In 2008 the Gulf of California jumbo squid fishery employed over 1,500 fishing vessels and was the fourth largest fishery in all of Mexico. By 2015, it had completely collapsed, and as of yet shows no sign of recovery.

To better understand the factors that drove the collapse and have inhibited recovery, the team compiled official fisheries records and reports, oceanographic data obtained from satellites and instruments deployed at sea, and biological measurements of over 1,000 individual squid. Comparing these data sources over time, the research team identified and described changes in ocean habitat that coincided with reductions in squid size, life span and fisheries productivity.

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