Genetic heterogeneity among pelagic egg samples and variance in reproductive success in an endangered freshwater fish, Hybognathus amarus (Cyprinidae)

A sweepstakes-mismatch process whereby reproduction is poorly coordinated with appropriate resources for larval development and recruitment can result in large variance in reproductive success among individuals and spawning aggregations. This process has been proposed to explain low ratio of genetic...

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Bibliographic Details
Published in:Environmental biology of fishes 2005-08, Vol.73 (4), p.463-472
Main Authors: OSBORNE, Megan J, BENAVIDES, Melissa A, TURNER, Thomas F
Format: Article
Language:English
Subjects:
Agnatha. Pisces
Animal and plant ecology
Animal reproduction
Animal, plant and microbial ecology
Animals
Aquatic organisms
Autoecology
Biological and medical sciences
Cyprinidae
Fecundity
Fish
Freshwater
Freshwater fish
Fundamental and applied biological sciences. Psychology
Heterogeneity
Hybognathus amarus
Larval development
Life history
Population number
Reproduction
Spawning
Vertebrata
Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
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Summary:A sweepstakes-mismatch process whereby reproduction is poorly coordinated with appropriate resources for larval development and recruitment can result in large variance in reproductive success among individuals and spawning aggregations. This process has been proposed to explain low ratio of genetic effective population size (N^sub e^) to adult census size (N) ratios in marine species with high fecundity, pelagic spawning, and extensive mortality in early life stages. This process is also hypothesized to also account for very low N^sub e^/N ([asymptotically =] 0.001) observed in the federally endangered Rio Grande silvery minnow, Hybognathus amarus. This species is a freshwater fish that shares life-history features with marine pelagic spawners. We tested two key predictions of the sweepstakes-mismatch hypothesis using molecular data: (i) that temporally distinct samples of eggs differ in genetic composition and, (ii) that egg samples do not comprise a random subset of potential adult breeders. We present genetic data that supports both predictions and that are consistent with the hypothesis that high variance in reproductive success among adult breeders is an important factor that lowers N^sub e^/N in H. amarus. This study highlights the importance of understanding the interaction of early life history and fragmentation in devising conservation plans for endangered aquatic organisms.[PUBLICATION ABSTRACT]
ISSN:0378-1909
1573-5133
DOI:10.1007/s10641-005-3215-3