Important details of the reproductive ecology of many freshwater fishes of the species-rich southeastern USA are still poorly known. Two such species are Notropis asperifrons (Burrhead Shiner), and Notropis stilbius (Silverstripe Shiner). Both are endemic to the Mobile Basin, AL. To determine timing and patterns of reproductive effort, collections were made of as many as 20 individuals of each species at roughly four-week intervals from March through September. Female gonadal somatic index (GSI) data averages for each collection indicate that both species peak in reproductive activity in April. Both species still had reproductively competent female GSI values as late as July 31. Examination of ovarian tissue indicates that Burrhead Shiner oocytes are usually larger at equivalent developmental stages. Burrhead Shiners exhibit sexual size dimorphism with larger females, while Silverstripe Shiners do not.
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1 December 2007
Observations on the Reproductive Biology of Two Notropis Shiner Species
Bruce Stallsmith,
Kevin Butler,
Amy Woodall,
Bob Muller
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