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

GROWTH PARAMETERS OF WILD AND SELECTED STRAINS OF ATLANTIC SALMON
(Salmo salar) ON TWO EXPERIMENTAL DIETS
William R. Wolters*, Frederic T. Barrows, Gary S. Burr and Ronald W. Hardy
USDA, ARS National Cold Water Marine Aquaculture Center
25 Salmon Farm Road
Franklin, ME 04634 USA
bill.wolters@ars.usda.gov
Two Atlantic salmon strains, one wild and one selected, were cultured from parr to smolt size to evaluate growth parameters,
feed consumption, and feed conversion. Each strain was fed diets formulated to represent either a traditional high protein, lower
energy salmon diet (46% protein, 18% fat) or a newer high energy diet (40% protein, 32% fat).
Atlantic salmon parr from Penobscot (wild) and St. John’s River (selected) strains were cultured in 265-liter tanks filled with
2-3 ppt salinity well water and connected to a common bio-filter system. Salmon parr were stocked at approximately 5 kg/m3
(100 fish/tank) and fed one of two experimental diets in a 2 x 2 factorial design with 4 replicate tanks for each treatment. Fish
were fed to apparent satiation with feed amounts adjusted weekly. Both diets were produced using twin-screw cooking extrusion,
and fish oil was vacuum coated after manufacture. Fish were anesthetized, counted and weighed at approximately 2 week
intervals. Analysis of variance was used to determine the effects of strain, diet, and diet × strain interaction on initial weight,
day 163 weight, specific growth rate, thermal growth coefficient, % feed consumed/day, and feed conversion ratio.
There were significant strain differences in initial weight, day 163 weight, specific growth rate, % feed consumed per day,
and thermal growth coefficient. Diet also had a significant effect on day 163 weight, specific growth rate, and thermal growth
coefficient. There were no differences from strain or diet for feed conversion or strain × diet interactions. St. John’s strain
salmon grew faster and were larger after 163 days (117.2+2.5g) than Penobscot River salmon (71.2+2.5g) (Figure 1). Although
diet had a significant effect, 163 day weight was different between the two experimental diets only for St. John’s River fish
(99.0+2.0 and 89.4+2.0g). Strain differences accounted for 85.9% of the difference in 163 day weight compared to 14.2% due
to diet. Results indicate St. John’s River salmon, which are commercially cultured and are being used in selective breeding
programs, have superior growth compared to wild, unselected Penobscot River salmon, and have even faster growth when fed
modern type diets.
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