Food for Thought: Connecting Zooplankton Science to Management in the San Francisco Estuary

Abstract

Pelagic fish in the San Francisco Estuary (estuary) are harder to catch in recent decades. Over the past thirty years, Delta Smelt catch in the Fall Midwater Trawl (FMWT) has declined by 99%, Longfin Smelt catch has declined by over 95%, and even the notoriously hardy Striped Bass have declined by over 75% (California Department of Fish and Wildlife [CDFW] FMWT data, unpublished, see “Notes”). To manage the system and reverse these declines, we need a better understanding of the “bottom-up” processes that exert control on these populations—we need to study fish food. In other words, in addition to studying fish directly, we need to increase our understanding of what pelagic fish eat: zooplankton (Brown et al. 2016).