HATCHING TIME AND EARLY GROWTH OF AGE-0 BLACK GRAPPLES, WHITE CRAPPIES, AND THEIR NATURALLY PRODUCED F1 HYBRIDS IN WEISS-LAKE, ALABAMA

Extensive natural hybridization occurs between black crappie Pomoxis n igromaculatus and white crappie P. annularis in Weiss Lake, Alabama. F irst-generation (F-1) hybrids have faster annual growth than black cra ppies and white crappies in this reservoir. However, no information ex ists on hatching date and early growth differences among black crappie s, white crappies, and F-1 hybrid offspring. We collected age-0 crappi es in early August 1992-1994 from Weiss Lake and identified species an d their hybrids with starch gel electrophoresis. Hatching date and ear ly growth were determined from otoliths. Swim-up dates of F-1 hybrids peaked about a week earlier than those of parental species. The growth rate of F-1 hybrids (0.86 mm/d) was significantly higher than those o f black crappies (0.67 mm/d) and white crappies (0.72 mm/d). Back-calc ulated lengths at ages 10, 70, and 30 d were higher for F-1 hybrids co mpared with black crappies. Thus, the faster growth of F-1 hybrids sta rts just after hatching and continues throughout life.