Robert Humston

Temporal Variation in Trace Element Chemistry of Fish Otoliths: Implications for Identifying Natal Origins in River Systems

Otolith chemistry has demonstrated potential for identifying natal origins and tracing dispersal in fisheries across a variety of habitats. Our objective was to assess inter-annual and intra-annual (specifically, within the spawning season) variation of trace element signatures distinguishing different rivers. Our study site was the Upper James River and its tributary the Maury River in western Virginia. We collected smallmouth bass (Micropterus dolomieu) fry from various locations along the length of the Maury River and also from the James within 10 km of their confluence. In 2005 fry...

Geologic Analyses for Evaluating Watershed Heterogeneity: Implications for Otolith Chemistry Studies

Studies using otolith chemistry to distinguish fish stocks in fresh waters have suggested that spatial heterogeneity in basin geology determines the scale of stock discrimination possible with this approach. However, no studies have illustrated an association between spatial variation in fish otolith chemistry and watershed geology. We consider this relationship in the context of a recent study describing within- and between-river variation in trace element chemistry of otoliths from YOY smallmouth bass (Micropterus dolomieu) from the Maury and James rivers (Virginia). Cluster analysis of...