Gonadosomatic index and fecundity of Lower Missouri and Middle Mississippi River endangered pallid sturgeon estimated using minimally invasive techniques

Abstract

Summary Minimally invasive, non‐lethal methods of ultrasonography were used to assess sex, egg diameter, fecundity, gonad volume, and gonadosomatic index, as well as endoscopy to visually assess the reproductive stage of Scaphirhynchus albus. Estimated mean egg diameters of 2.202 ± 0.187 mm and mean fecundity of 44 531 ± 23 940 eggs were similar to previous studies using invasive techniques. Mean S. albus gonadosomatic indices (GSI) for reproductive and non‐reproductive females were 16.16 and 1.26%, respectively, while reproductive and non‐reproductive male GSI were 2.00 and 0.43%, respectively. There was no relationship between hybrid status or capture location and GSI. Mean fecundity was 48.5% higher than hatchery spawn estimates. Fecundity increased as fork length increased but did so more dramatically in the upper river kilometers of the Missouri River. By examining multiple fish over multiple years, the reproductive cycle periodicity for hatchery female S. albus was found to be 2–4 years and river dwelling males 1–4 years. The use of ultrasonic and endoscopic methods in combination was shown to be helpful in tracking individual gonad characteristics over multi‐year reproductive cycles.

Determination of annual reproductive cycle in male sterlet, Acipenser ruthenus using histology and ultrasound imaging

“…In this context, some descriptions of ultrasonic images have been used for better characterization of fish gonad (Jennings et al, 1996;Bryan et al, 2007). The ultrasound imaging also can be used to determine some parameters such as size of the ovary or testis and gonad shape (Albers et al, 2013). However, some other parameters including fecundity and GSI might be determined via further analyses (Bryan et al, 2007).…”

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

“…The development of ultrasonography as a technique to assign sex and stage of maturity in sturgeon has been the fastest growing technique and has been reported for multiple species, including Persian sturgeon ( Acipenser persicus , Vajhi, Veshkini, Masoudifard, Moghim, & Molazem, ); stellate sturgeon ( Acipenser stellatus , Moghim, Vajhi, Veshkini, & Masoudifard, ); Adriatic sturgeon x Siberian sturgeon ( Acipenser naccarii x Acipenser baerii , Petochi et al., ); sterlet ( Acipenser ruthenus ) , beluga ( Huso huso ) , Siberian sturgeon ( Acipenser baerii ), Russian sturgeon ( Acipenser gueldenstaedtii ) , Huso huso x Acipenser ruthenus, Acipenser gueldenstauedtii x Acipenser baerii (Chebanov & Galich, ); white sturgeon ( Acipenser transmontanus ), green sturgeon ( Acipenser medirostris , Van Eenennaam, Linares, & Doroshov, ; Van Eenennaam, unpubl. data); lake sturgeon ( Acipenser fulvescens , Chiotti, Boase, Hondorp, & Briggs, ); Russian sturgeon (Memiş et al., ); Chinese sturgeon ( Acipenser sinensis , Du et al., ); Siberian sturgeon (Munhofen, Jiménez, Peterson, Camus, & Divers, ); shovelnose sturgeon (Colombo, Wills, & Garvey, ; Wildhaber et al., ; Bryan et al., ; Wildhaber et al., ); and pallid sturgeon (Albers, Wildhaber, & DeLonay, ).…”

Physical characteristics and simulated transport of pallid sturgeon and shovelnose sturgeon eggs

“…Egg diameter was previously reported as 2.3-3.1 mm for pallid sturgeon (Keenlyne et al 1992;DeLonay et al 2012;George et al 2012;Albers et al 2013) and 2.3-3.2 mm for shovelnose sturgeon (Moos 1978;Henry and Ruelle 1992;Bryan et al 2007). Our measurements of the diameter of both pallid sturgeon and shovelnose sturgeon eggs were similar to those reported by others.…”