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Species-specific microsatellite DNA markers were used to identify hybrids of black crappies Pomoxis nigromaculatus and white crappies P. annularis and to determine the effect of hybridization on crappie growth. Specifically, we determined the contribution of hybrids to the skew in length frequency distributions that is frequently observed within year-classes of sympatric crappie populations and the resulting upward bias on growth estimates for the two species. Hybridization was found throughout most southern Minnesota Fakes that contained both species, but the frequency of hybrids was low in our length-stratified subsamples (mean frequency of first-generation [F1] hybrids among all lakes and year-classes = 3.2%; mean frequency of advanced-generation [Fx] hybrids = 1.4%). Among the 22 study lakes, only 2 contained no hybrids (based on polymerase chain reaction amplification of microsatellite loci). The F1 hybrids were disproportionately classified as black crappies under a Minnesota Department of Natural Resources (MNDNR) classification system that only allowed assignment of crappies to the two parental species. In one lake sampled over multiple years, we found F1 hybrids in only 5 of 14 year-classes of MNDNR-classified black crappies and in 4 of 11 year-classes of MNDNR-classified white crappies, indicating annual variation in the prevalence of hybridization. Consistent with their faster growth and tendency to be classified as black crappies, F1 hybrids accounted for 82% of all statistical outliers in length distributions of MNDNR-classified black crappie age-classes and 33% of the infrequent outliers in MNDNR-classified white crappie age-classes. The presence of F1 hybrids in our subsamples produced an upward bias in back-calculated length estimates for black crappies but had nonsignificant effects on white crappie length estimates. The effects of hybridization should be taken into account when estimating growth in crappie species from sympatric populations. [ABSTRACT FROM AUTHOR]

Presents articles related to molecular ecology. Development and characterization of microsatellite markers in Camellia japonica L.; Discussion of microsatellites in walleye Stizostedion vitreum; Isolation and characterization of microsatellites in albatrosses; Others.

Presents a study of genetic microsatellites in the walleye, Stizostedion vitreum, a sport fish species mainly found in the North American waters. Characterization and development of the microsatellites; Description of the methods of the study; Results, conclusions and discussion.