Hatchery Performance Attributes of Juvenile Lake Sturgeon Fed Two Natural Food Types
E.T. Volkman, K.L. Pangle, D.A. Rajchel, T.M.
Sutton-2004
North American Journal of Aquaculture, 66(2):
105–112
Abstract:
The use of stocking programs to rehabilitate
depressed populations of lake sturgeon Acipenser
fulvescens requires the optimization of early life stage growth in
hatchery settings. We evaluated the performance of juvenile lake sturgeon
fed different proportions of two natural food types—adult brine shrimp Artemia
spp. and larval bloodworms Chironomus
spp.—over a 10-week laboratory experiment. The following five diet
treatments were provided: (1) 100% bloodworms; (2) 75% bloodworms : 25%
brine shrimp; (3) 50% bloodworms : 50%
brine shrimp; (4) 25% bloodworms : 75%
brine shrimp; and (5) 100% brine shrimp. Lake sturgeon growth was positively
related to bloodworm content in the diet and was significantly different
among treatments. Although the initial sizes of fish were similar, mean fork
length and wet weight were greatest for the 100% bloodworm treatment (183.1
mm and 37.5 g, respectively) and lowest for the 100% brine shrimp diet
(118.4 mm and 9.5 g) by the end of the study. Mean specific and absolute
growth rates in length (0.93% and 1.28 mm/d, respectively) and weight (2.61%
and 0.45 g/d) were greatest for the 100% bloodworm diet, followed by the
other treatments in order of decreasing amount of bloodworms in the diet.
Percent weight gain (525%) and food conversion efficiency (67%) were also
greatest for the 100% bloodworm diet, followed by the other treatments in
order of decreasing dietary bloodworm content. Whole-body protein (13.9%),
lipid (2.5%), and gross-energy (3.77 kJ/g) content were greatest for fish
fed 100% bloodworms, with these proximate-composition measures also ranked
in order of decreasing dietary bloodworm content for the other treatments.
We recommend that juvenile lake sturgeon reared in hatchery environments be
fed high proportions of bloodworms to maximize growth, body size, and lipid
content for rehabilitation stocking programs.
(Purdue University, Department of Forestry and
Natural Resources, 195 Marsteller Street, West Lafayette, Indiana 47906,
USA)