Natal Origin of North Carolina Central Southern Management Area Striped Bass Morone saxatilis Determined by Otolith Chemistry

Striped bass are one of the most important recreational fisheries in the state of North Carolina. The NC Wildlife Resource Commission stocks striped bass into the Neuse and Tar River systems (Central Southern Management Area) on an annual basis. Both systems have spawning populations, but no age zero fish have been collected in these river systems to support this. Striped bass are anadromous and, although highly migratory, evidence has shown they return to their natal streams to spawn. Water samples from these watersheds will be collected and analyzed using elemental microchemistry to determine watershed signature. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) will be used to determine concentrations of the trace elements Sr, Ba, Mg, and Mn in the water samples in order to identify a signature for each watershed. Fish will be collected from the study watersheds four times per year for two years. Length and weight of each fish will be taken to determine Fulton’s condition factor (K-factor). Gonads will be weighed to determine gonadal somatic index (GSI). Livers will be weighed to determine Liver Somatic Index (LSI). These measurements will be used to determine the condition of the fish at time of capture. Scales and otoliths will be removed for ageing. Otoliths will be removed and the cores and cross sections analyzed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) to determine concentrations of the trace elements Sr, Ba, Mg and Mn. The trace elemental concentrations of the otoliths will be compared to the elemental signatures established for the Tar and Neuse River Systems to determine if these watersheds are the natal origin of the striped bass collected within them.