Hatching Time and Early Growth of Age-0 Black Crappies, White Crappies, and Their Naturally Produced F1Hybrids in Weiss Lake, Alabama

Abstract

Abstract Extensive natural hybridization occurs between black crappie Pomoxis nigromaculatus and white crappie P. annularis in Weiss Lake, Alabama. First-generation (F1) hybrids have faster annual growth than black crappies and white crappies in this reservoir. However, no information exists on hatching date and early growth differences among black crappies, white crappies, and F1 hybrid offspring. We collected age-0 crappies in early August 1992–1994 from Weiss Lake and identified species and their hybrids with starch gel electrophoresis. Hatching date and early growth were determined from otoliths. Swim-up dates of F1 hybrids peaked about a week earlier than those of parental species. The growth rate of F1 hybrids (0.86 mm/d) was significantly higher than those of black crappies (0.67 mm/d) and white crappies (0.72 mm/d). Back-calculated lengths at ages 10, 20, and 30 d were higher for F1 hybrids compared with black crappies. Thus, the faster growth of F1 hybrids starts just after hatching and continues...