Fig. 3.

Monthly summed observations in Monterey Bay of Pacific hake, M. productus (in gray, left y axis) and Humboldt squid, D. gigas (in dark red, inverted right y axis) normalized by hours of ROV deployment. The Niño 3 index (in bright red, inverted right y axis) is based on averages of sea-surface temperature (SST) in the equatorial Pacific (http://ingrid.ldeo.columbia.edu/SOURCES/Indices). The increased observations of D. gigas began shortly after the increased SST of the equatorial Pacific in 1997 and in 2002. Observations of hake decreased after the squid reappeared, but they rose again between 1999 and 2002, the period when D. gigas was absent.