February 15-18, 2009 Washington State Convention Center Seattle ...

VARIATION OF EGG SIZE OF DOMESTIC WHITE BASS Morone chrysops DUE TO
DIETARY DIFFERENCES
Matthew McEntire* and S. Adam Fuller
USDA / ARS – H.K. Dupree Stuttgart National Aquaculture Research Center
P.O. Box 1050
2955 Hwy 130 East
Stuttgart, Arkansas 72160-1050 USA
Matthew.mcentire@ars.usda.gov
Tagged domestic three year old white bass brood fish were stocked in 5500 L tanks at the Harry K. Dupree Stuttgart National
Aquaculture Research Center with flow through well water mimicking a normal thermal and diurnal pattern in the South Eastern
USA. There were two groups of fish fed different diets during most of vitellogenesis. The control group was fed a 45%
protein 16% fat diet containing primarily fish meal and the other was fed a 45% protein, 15% fat diet containing fish meal and
squid meal. Fish were of the same age and genetic stock but held at different facilities prior to stocking. The mean (+ S.E.) fish
weights were 714+121g for the control group and 558+105g for group fed the diet containing squid meal and were statistically
different (p< 0.0001). In April fish were injected with a slow release gonadotropin-releasing hormone (GnRH) pellet to induce
oocyte maturation and ovulation.
Eggs were collected from 54 white bass females and preserved in 70 % isopropyl alcohol. All the egg samples were treated
the same and the amount of shrinkage in egg size was expected to be uniform and constant across groups. The eggs were later
photographed and mean relative egg size was measured to the nearest mm (n=30). The mean egg diameter was 0.85+0.05mm
for the control and 0.86+0.06mm for the diet containing squid meal. There was no statistical difference in egg sizes between
the groups (p