Delta smelt: Life history and decline of a once abundant species in the San Francisco Estuary

San Francisco Estuary and Watershed Science
By: , and 

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Abstract

This paper reviews what has been learned about Delta Smelt and its status since the publication of The State of Bay-Delta Science, 2008 (Healey et al. 2008). The Delta Smelt is endemic to the upper San Francisco Estuary. Much of its historic habitat is no longer available and remaining habitat is increasingly unable to sustain the population. As a listed species living in the central node of California’s water supply system, Delta Smelt has been the focus of a large research effort to understand causes of decline and identify ways to recover the species. Since 2008, a remarkable record of innovative research on Delta Smelt has been achieved, which is summarized here. Unfortunately, research has not prevented the smelt’s continued decline, which is the result of multiple, interacting factors. A major driver of decline is change to the Delta ecosystem from water exports, resulting in reduced outflows and high levels of entrainment in the large pumps of the South Delta. Invasions of alien species, encouraged by environmental change, have also played a contributing role in the decline. Severe drought effects have pushed Delta Smelt to record low levels in 2014–2015. The rapid decline of the species and failure of recovery efforts demonstrate an inability to manage the Delta for the “co-equal goals” of maintaining a healthy ecosystem and providing a reliable water supply for Californians. Diverse and substantial management actions are needed to preserve Delta Smelt.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Delta smelt: Life history and decline of a once abundant species in the San Francisco Estuary
Series title San Francisco Estuary and Watershed Science
DOI 10.15447/sfews.2016v14iss2art6
Volume 14
Issue 2
Year Published 2016
Language English
Publisher University of California at Davis John Muir Institute of the Environment and the Delta Stewardship Council
Contributing office(s) California Water Science Center, San Francisco Bay-Delta
Description 30 p.
Country United States
State California
Other Geospatial San Francisco Bay
Online Only (Y/N) N
Additional Online Files (Y/N) N