Temporal and Spatial Variability in Otolith Trace-Element Signatures of Juvenile Striped Bass from Spawning Locations in Lake Texoma, Oklahoma-Texas

Abstract

We assessed the potential of trace-element analysis for identifying spawning locations of striped bass Morone saxatilis in the two tributaries of Lake Texoma, Oklahoma-Texas, during 2002-2004. We also assessed the temporal stability of elemental signatures over 3 years. Elemental composition of juvenile striped bass otoliths varied considerably between the two tributary arms of Lake Texoma both within and among years. Overall reclassification rates within each collection year ranged between 81% and 93%. However, because of high interannual variability, classification functions could not reliably predict natal areas for individuals from other year-classes (19-62%). Although the mechanisms generating spatial and temporal differences in otolith chemistry are not well understood, spatial differences in otolith chemistry indicate that elemental fingerprints of striped bass from the two natal rivers in the Lake Texoma system provide natural tags of juvenile habitat. The temporal variability we observed in otolith elemental signatures complicates the use of these signatures for determining the natal river of an unknown individual from an unsampled year-class. However, building a library of trace-element signatures for yearly cohorts should make it possible to determine natal rivers for adult striped bass from known cohorts.