Life History Diversity in Post-Spawn Female Steelhead Trout Assessed Using Plasma Estradiol-17β: Relationship with Growth and Energy Reserves
Post-spawning female steelhead trout (Oncorhynchus mykiss, kelt) reconditioning is a recovery tool addressing ESA-threatened Snake River steelhead populations. Kelt reconditioning capitalizes on iteroparity, the ability to repeat spawn, and natural selection that occurs prior to initial spawning. Wild kelts are captured, fed, and released to migrate upstream, and spawn naturally without a return to the ocean. Hatchery-origin kelts are reconditioned as a research model. After maiden spawning, kelts may spawn again after 1 year (consecutive spawner) or after 2 years (skip spawner). Kelts on the consecutive trajectory (rematuring) can be distinguished from kelts on the skipping trajectory (non-rematuring) by elevated plasma estradiol-17β (E2) levels 6 months prior to spawning.
Jenkins, l., A. Pierce, N. Graham, L. Medeiros, R. Branstetter, S. Everett, D. Hatch, and J. Nagler. 2017. Life History Diversity in Post-Spawn Female Steelhead Trout Assessed Using Plasma Estradiol-17β: Relationship with Growth and Energy Reserves. American Fisheries Society Western Division and Montana Chapter Annual Meeting, Missoula, MT, May 2017.