White Sturgeon Sex and Stage of Maturity in Lower Columbia River, Canada

Knowledge pertaining to when hatchery-origin White Sturgeon become reproductively mature and contribute to spawning occurring in the wild population is critical to informing management decisions for the population. Accordingly, the objectives of this project are to: 1. Determine sex and stage of maturity using multiple methods, estimate age at first maturity and, if applicable, spawning periodicity of hatchery-origin White Sturgeon in the lower Columbia River, Canada. 2. Determine sex and stage of maturity using multiple methods and spawning periodicity of wild White Sturgeon in the lower Columbia River, Canada. Reproductive indices will be developed for the wild population through collection of biological samples during the course of the study as well as using a long-term sex and stage of maturity dataset developed based on multiple captures of adults over the past decade within the study area. 3. Determine accuracy across multiple methods used to assign sex and stage of maturity to hatchery-origin and wild White Sturgeon in the lower Columbia River, Canada. Methods tested will include ultrasound, endoscopy (otoscope and endoscope), and measurement of plasma sex steroids. Histological analysis of gonadal tissue collected by biopsy will be used to validate true sex and stage of maturity. In order to validate histological analysis of the gonad as a control for sex and stage at maturity in this study, the following sub-objectives will be evaluated: 3.1. Determine homogeneity of stage of maturity across gonadal tissue in both female and male White Sturgeon of hatchery-origin in the lower Columbia River, Canada. 3.2. Determine the accuracy of gonadal biopsy in assessing stage of maturity in hatchery-origin White Sturgeon in the lower Columbia River, Canada. 4. Compare reproductive indices for hatchery-origin White Sturgeon to the wild breeding population including sex ratio, estimated age at first maturity, and spawning periodicity. 5. Determine how age, size, and habitat influence growth and reproductive indices for hatchery-origin White Sturgeon.