Environmental Modulation of Marine Productivity and Annual Fish Catch Along the Coast of Peru

This study considers ocean–atmosphere influences on marine productivity over the shelf of Peru. Annual fish catch since 1961 and monthly satellite phytoplankton fluorescence (FLH) since 1997 in the area 7–14 S, 80–76 W provide a basis for statistical evaluation of environmental indicators from reanalysis fields. Monthly FLH is correlated with the year-on-year change in (anchovy) fish catch, wherein the autumn season (Mar–Aug) shows optimal association. The temporal record of FLH is regressed onto various fields, and the upper and lower 10 years are identified for composite analysis. Statistical results link the Southern Oscillation to wind patterns and oceanic response, wherein greater anchovy catch tends to follow La Niña. A case study is made of the change from El Niño in 2023 to La Niña in 2024. Composites indicate that cyclonic wind vorticity spreads phytoplankton across the Peruvian shelf under La Niña, resulting in a 33% increase in fluorescence from 0.26 to 0.39.