Five decades (1972-2020) of zooplankton monitoring in the upper San Francisco Estuary.

We present the longest available dataset (by 15 years) of estuarine zooplankton abundance worldwide. Zooplankton have been monitored throughout the upper San Francisco Estuary from 1972 -present due to its status as a central hub of California water delivery and home to commercially important and endangered fishes. We integrated data from five monitoring programs, including over 300 locations, three size-classes of zooplankton targeted with different gears, over 80,000 samples, and over two billion sampled organisms. Over the duration of this dataset, species invasions have driven community turnover, periodic droughts have occurred, and important fishes have declined, likely due in part to reduced food supply from zooplankton. Data from the individual surveys have been used in prior studies on issues related to species invasions, flows, fish diets and population dynamics, zooplankton population dynamics, and community ecology. Our integrated dataset offers unparalleled spatio-temporal scope to address these and other fundamental ecological questions.