title: Documenting utility of paddlefish otoliths for quantification of metals using inductively coupled plasma mass spectrometry.
abstract: BACKGROUND
  The otoliths of the inner ear of fishes record the environment of their surrounding water throughout their life. For paddlefish (Polyodon spathula), otoliths have not been routinely used by scientists since their detriments were outlined in the early 1940s. We sought to determine if paddlefish otoliths were useful for resolving elemental information contained within.
  
  
  METHODS
  Adult paddlefish were collected from two wild, self-sustaining populations in Oklahoma reservoirs in the Arkansas River basin. Juveniles were obtained from a hatchery in the Red River basin of Oklahoma. Otoliths were removed and laser ablation, inductively coupled plasma mass spectrometry (ICP-MS) was used to quantify eight elements (Li, Mg, Mn, Rb, Sr, Y, Ba, and Pb) along the core and edge portions, which were analyzed for differences between otolith regions and among paddlefish sources.
  
  
  RESULTS
  Differences were found among samples for six of the eight elements examined. Otoliths from Red River basin paddlefish born in a hatchery had significantly lower amounts of Mg and Mn, but higher levels of Rb than otoliths from wild paddlefish in the Arkansas River basin. Concentrations of Y, Sr, and Ba were reduced on the edges of adult paddlefish from both reservoirs compared with the cores.
  
  
  CONCLUSIONS
  This research shows the utility of using an ICP-MS analysis of paddlefish otoliths. Future research that seeks to determine sources of paddlefish production, such as which reservoir tributaries are most important for reproduction or what proportion of the population is composed of wild versus hatchery-produced individuals, appears promising.
authors.affiliation: US Geological Survey, Oklahoma Cooperative Fish and Wildlife Research Unit, Oklahoma State University, Stillwater, OK 74078, USA. longjm@okstate.edu
authors.forename: James M
authors.initials: JM
authors.lastname: Long
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Schaffler
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000835:Animals, Wild; D017753:Ecosystem; D005398:Fisheries; D005399:Fishes; D013058:Mass Spectrometry / Q000379:methods*; D008670:Metals / Q000032:analysis*; D009825:Oklahoma; D010037:Otolithic Membrane / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D008670:Metals