Effects of Temperature on
the Early Development, Growth, and Survival of Shortnose Sturgeon, Acipenser
brevirostrum, and Atlantic Sturgeon, Acipenser
oxyrhynchus, Yolk-Sac Larvae
R.S. Hardy, M.K. Litvak-2004
Environmental Biology of Fishes, 70(2):
145-154
Abstract:
We reared shortnose and Atlantic sturgeons at
different temperatures after hatch and measured yolk utilization rate and
efficiency (YUE), maximum standard length, survival and development of
escape response. Newly hatched Atlantic sturgeon, were smaller in size, more
efficient at utilizing yolk (incorporating yolk to body tissue) and reached
developmental stages sooner than shortnose sturgeon reared at the same
temperatures (13–15°C).
Within each species, decreasing temperature delayed yolk absorption, escape
initiation, time to reach maximum size, and time to 100% mortality. However,
YUEs and the size of the larvae at these 'stages' were independent of
rearing temperature for both species. These results suggest that even as
temperature drives metabolic processes to speed up development, these two
species are still extremely efficient at transferring yolk energy to body
tissues. The lower efficiencies experienced by larval shortnose may reflect
difference in yolk quality between the two species and/or the Atlantic
sturgeon's higher conversion efficiency. The ability of these two sturgeon
species to develop successfully and efficiently under a wide range in
temperatures may provide a competitive advantage over more stenothermic
species and explain their persistence through evolutionary time.
(Idaho Department of Fish and Game,
2750 Kathleen Avenue, Coeurd'Alene, ID 83815, U.S.A., e-mail: rhardy@idfg.state.id.us,
e-mail of M.K. Litvak: litvak@unbsj.ca)