Kl. Pope et Dr. Devries, INTERACTIONS BETWEEN LARVAL WHITE CRAPPIE AND GIZZARD SHAD - QUANTIFYING MECHANISMS IN SMALL PONDS, Transactions of the American Fisheries Society, 123(6), 1994, pp. 975-987
To test potential competitive interactions between larvae of white cra
ppie Pomoxis annularis and of gizzard shad Dorosoma cepedianum, we add
ed adult gizzard shad to eight of twelve 0.1-ha ponds that had been st
ocked with adult white crappies. Larval white crappies and larval gizz
ard shad appeared within 1 week of one another and larval white crappi
e density did not differ between treatments. Zooplankton density decli
ned similarly between treatments, and zooplankton species composition
and size did not differ. Although larval white crappie and larval gizz
ard shad had moderate diet overlap, prey selection by white crappie di
d not differ between treatments. During April, more than 70% of larval
gizzard shad had empty stomachs, compared with less than 20% of larva
l white crappies. Age-0 gizzard shad recovery was extremely low (< 10
kg/ha) in five of eight ponds. Daily ring counts from otoliths indicat
ed that late-spawned gizzard shad had higher growth rates than early-s
pawned gizzard shad, whereas no such relationship existed for white cr
appie. At a given size, age-0 white crappies weighted more in ponds wi
th gizzard shad than in ponds without them. Contrary to our prediction
s, gizzard shad did not negatively affect age-0 white crappies.