Fig. 3. Changes in the distribution of forage species distribution off California in the year preceding (2013) and during the marine heatwave (2014–2016).

a–d Mid-water trawl catches (catch-per-unit-effort; CPUE) of total northern anchovy; e–h acoustically determined (NASC; m² nmi⁻²) krill distribution and abundance, averaged onto a 25 km² grid. All survey data are derived from the Rockfish Recruitment and Ecosystem Assessment Survery (RREAS) during May–June. Dashed box indicates the long-term core sampling region of the RREAS; from Point Reyes 38° N to Monterey Bay 36.5° N. Map contours are the 200 m, 1000 m, and 2000 m isobaths (inshore to offshore; labeled in a). i, j Changes in the mean (error bars denote 95% confidence intervals) relative abundance of total anchovy (blue) and krill (red), and corresponding changes in spatial intensity and clustering (indexed by Moran’s I) for the mapped distributions per year. Source data are provided as a Source Data file.