Use of Ultrasound Imaging and Steroid Concentrations to Identify Maturational Status in Adult Steelhead
| Autor: | Lisbeth K. Siddens, Martin S. Fitzpatrick, Allen F. Evans |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
endocrine system
medicine.medical_specialty Gonad Ecology urogenital system business.industry Ultrasound Management Monitoring Policy and Law Aquatic Science Biology Andrology medicine.anatomical_structure Endocrinology Internal medicine medicine Ultrasound imaging Rainbow trout business Ecology Evolution Behavior and Systematics Testosterone |
| Zdroj: | North American Journal of Fisheries Management. 24:967-978 |
| ISSN: | 1548-8675 0275-5947 |
| DOI: | 10.1577/m03-112.1 |
| Popis: | We sought to develop a rapid, noninvasive, and accurate method for distinguishing prespawn (mature or maturing) adult steelhead (anadromous rainbow trout Oncorhynchus mykiss) from postspawn adults (kelts). Ultrasound images of gonads were collected, and levels of plasma testosterone (T), 11-ketotestosterone (11-KT), and 17α-hydroxy-20β-dihydroxyprogesterone (DHP) were determined for adult steelhead before and after spawning. Results demonstrated that ultrasound images provided quantifiable selection criteria (number of eggs or gonad size) for the identification of prespawn versus postspawn adults. Mature females were easily identifiable by the presence of numerous, well-developed eggs. Conversely, only a few mature eggs remained in the body cavities of female kelts. Ultrasound investigation of the maximum testis area demonstrated that testes undergo substantial size changes following spawning. Mean maximum testis area was 2.86 cm2 in prespawn males and 0.62 cm2 male kelts. Distributions of testis... |
| Databáze: | OpenAIRE |
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