A practical guide for assigning sex and stage of maturity in sturgeons and paddlefish

Abstract

The goal of this paper is to improve the assignment of sex and stage of maturity for sturgeons and paddlefish by providing both an overview of the gonadal stages of maturity and general guidelines and training needs for the four most commonly used techniques to assign sex and stage of maturity including ultrasound, endoscopy, plasma sex steroid analysis, and biopsy of the gonads via celiotomy. Sturgeons and paddlefish do not express external sexual dimorphism, which can make assignment of sex and stage of maturity challenging. Correct assignment of sex and stage of maturity is important for management of wild populations as well as for aquaculture, whether for conservation or commercial production. Selecting a technique to use when assigning sex and stage of maturity will depend on a number of factors; a comparison among these techniques is provided in this review, including tradeoffs, to help assist in technique selection based on specific research or production goals. The use of more than one technique may be beneficial to determine error rates associated with a single technique. This review is intended to serve as a practical resource when assigning sex and stage of maturity in field or laboratory settings in addition to stressing the importance of correctly identifying sex during research and in the management of populations.