Natural Recruitment Failure of Walleye in Tennessee
Reservoirs
Christopher S. Vandergoot *, Phillip W. Bettoli
Tennessee Cooperative Fishery Research Unit Tennessee
Technological University, 205 Pennebaker Hall or Box 5114,
Cookeville, TN 38505 Phone: (931) 372-3094 Fax: (931)
372-6257 Email: csv2001@tntech.edu
Email: pbettoli@tntech.edu
Dale C. Honeyfield
U.S. Geological Survey, Biological Resources
Division, Research and Development Lab, Rural Route 4, Box
63, Wellsboro, PA 16901, Phone: (570) 724-3322 ext. 233,
Fax: (570) 724-2525, Email: honeyfie@epix.edu
Keywords: Walleye, early mortality syndrome,
alewives, reproductive failure
Early Mortality Syndrome (EMS) has been linked to poor
reproductive success of salmonids in the Great Lakes and New
York Finger Lakes. Low thiamine concentrations in eggs are
indicative of the syndrome, causing high fry mortality. In
those northern lakes, salmonids feed on alewives Alosa
pseudoharengus, which contain thiaminase, a
thiamine-degrading enzyme, and thiamine concentrations in
brood fish and eggs are lowest where alewives are the
predominant prey item. Alewives are common in several
Tennessee reservoirs, particularly those where walleyes Stizostedion
vitreum suffer chronic recruitment problems. In spring
of 1999, we initiated a study to determine if a relationship
existed between poor reproductive success of walleyes and
the presence of alewives. Preliminary analysis revealed that
thiamine concentrations in walleye eggs were higher, not
lower, in systems where alewives were most abundant.
However, large differences in age and size structure among
alewife populations may have accounted for these initial
findings. Currently, the minimum concentration of thiamine
needed for normal embryonic development of walleye eggs is
unknown. To further investigate the relationship between
thiamine concentrations in walleye eggs and hatching
success, walleye eggs will be hatched and assayed for
thiamine from three different reservoirs with varying
densities of alewife in spring 2000.
Keywords: Walleye, early mortality syndrome, alewives,
reproductive failure
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