S. Adam Fuller
William R. Gould
Paul R. Turner
Dennis M. Hallford
Colleen A. Caldwell
2004
<p><span>Timing of gametogensis and thus spawning can be inferred through changes in plasma concentrations of gonadal hormones. In preparation for ovulation and spawning, mean concentrations of 17ß-estradiol in a population of Rio Grande chub (</span><i>Gila pandora</i><span>) occupying the Rio Bonito, New Mexico, peaked at 37.6 ng/mL on 16 June and declined to 1.50 ng/mL by 11 August. Similarly, the gonadal somatic index (GSI) increased from 9.02 on 21 May (</span><i>n</i><span> = 9) to 11.85 on 16 June (</span><i>n</i><span> = 2) and declined to 6.10 on 11 August (</span><i>n</i><span> = 2). Peak concentrations of 17ß-estradiol and elevated GSI in June coincided with peak daylength for the year (14 h and 12 min) and average water temperature of 15.1°C. Concentrations of 17ß-estradiol remained low through 3 October indicating no additional spawning events in the Rio Grande chub population. We demonstrated 17ß-estradiol is a nondestructive and thus useful tool in estimating timing of spawning in a wild fish population.</span></p>
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10.1894/0038-4909(2004)049<0311:SCIEOT>2.0.CO;2
en
Southwestern Association of Naturalists
Seasonal changes in 17-ß estradiol of the Rio Grande Chub (<i>Gila pandora</i>) in south-central New Mexico
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