Defining habitat quality for young-of-year Longfin Smelt

Defining habitat quality for young-of-year Longfin Smelt: historical otolith-based reconstructions of growth and salinity history in relation to geography, climate, and outflow

The Longfin Smelt population in San Francisco Bay has collapsed to < 1% of pre-1980s abundances.  Though several possible factors (e.g., freshwater outflow and prey abundance) have been implicated, little is known about the optimal environmental conditions needed by early life stages (e.g., larvae and juveniles). Using otolith-based growth and Sr isotope analyses, this study will provide historical chronologies of growth and salinity for hundreds of archived Longfin Smelt spanning the previous two decades. This will allow us to model (a) how habitat quality varies spatially throughout the bay, (b) how temporal variation in Longfin vital rates corresponds with recruitment dynamics, (c) the diversity of life history strategies used by Longfin, and (d) how life history and vital rates respond to changes in climate (e.g., drought and warming).