Oregon Sea Grant

Previous studies have shown that oceanographic conditions influence the distribution of range-expanding Humboldt squid (Dosidicus gigas), but broad-scale temporal and spatial distribution analyses are limited. Interannual variability in Humboldt squid occurrence is largely undocumented north of California. We combined annual occurrences noted by fishermen with fisheries-dependent and fisheries-independent data between 2002–11 from 42.0080˚N, 131.0000˚W to 46.7008˚N, 131.0000˚W. Humboldt squid more frequently occurred at a sea surface temperature range of 10.5˚–13.0˚C, sea surface height anomalies from –4.0–1.0 m, 0.26–3.00 mg m–3 chlorophyll a, and sea surface salinity range of 32.2–32.8 psu. Dissolved oxygen levels were bimodal, between 3.0–4.5 ml L–1 and 6.0–7.0 ml L–1 at 30 m depth. Maps of estimated likelihood of occurrence generated by nonparametric multiplicative regression were consistent with observations from fishermen. When Humboldt squid become abundant in northern California Current waters, research should include seasonal variability and oceanographic conditions at multiple depths.