Life history strategies of striped bass, Morone saxatilis, populations inferred from otolith microchemistry

• Published in: Fisheries research 2003-04, Vol.62 (1), p.53-63
• Main Authors: Morris, James A., Rulifson, Roger A., Toburen, Larry H.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); Freshwater; Fundamental and applied biological sciences. Psychology; Morone saxatilis; Otolith; PIXE; Population discrimination; Trace elements
• ISSN: 0165-7836; 1872-6763
• DOI: 10.1016/S0165-7836(02)00246-1

Otolith microchemistry was used to investigate genetic, demographic and life history characteristics of striped bass, Morone saxatilis. Striped bass were collected from three river systems along the eastern seaboard: the Neuse River and Roanoke River, North Carolina, USA and the Stewiacke River, Nova Scotia, Canada. The elemental ratios Mn:Ca, Fe:Ca, Br:Ca, Zn:Ca, Cu:Ca and Sr:Ca were measured in otolith nuclei using broad-beam particle induced X-ray emission (PIXE) spectroscopy. Elemental ratios were not significantly different between several Roanoke River genotypes. Two dorsal coloration patterns found in Stewiacke River striped bass indicate the presence of ocean-going (green) and resident (black) contingents, but results of trace elemental analysis showed no differences in elemental signatures of otolith nuclei suggesting that the contingents originate from the same population. Observed Sr:Ca ratios were not stable between Roanoke River year classes; decreased levels of strontium found in 1 year class corresponded with a flooding event. Discriminant analysis using these six elemental ratios correctly identified approximately 88% of the Neuse River, 79% of Stewiacke River, and 47% of the Roanoke River striped bass to the river system from which they were caught during spawning activity. Misclassified individuals might be a result of environmental variability from subhabitats or represent wandering individuals from other populations. The Neuse River population, which is considered to be an endemic riverine population, had no obvious outliers. Results of this study show the increased power of information gathering provided by otolith microchemistry when used in concert with phenotypic and genotypic classification techniques.