EMS results from a depletion of vitamin B1 (thiamine) that is brought about by female salmonids ingesting thiaminase-containing forage fish, such as the alewife or smelt. The female is then unable to encapsulate enough thiamine into her eggs to allow the juveniles to survive. EMS can cause up to 100% mortality in hatchery raised fish such as salmon and lake trout. This mortality typically occurs just after juvenile fish hatch and are still utilizing the yolk sac for food. By correlating the concentration of egg-thiamine with juvenile mortality, we get an estimate of EMS for the Atlantic salmon we raise here at LSSU. We are currently monitoring the long term trends of EMS in these Atlantic salmon as a potential indicator of Lake Huron thiamine status.
Thiaminase is the enzyme that degrades vitamin B1 (thiamine). A better understanding of thiaminase, the root cause of EMS, will hopefully provide a better understanding of this complex disease. We are currently examining the biochemistry of this enzyme using modern molecular biological tools. This includes the development of new tools to look for the presence of thiaminase in Great Lakes fishes.
The research projects related to EMS provide a unique opportunity for undergraduates to perform research in an active area of Great Lakes research. These projects supply data to management agencies such as the Michigan Department of Natural Resources that aid them in making management decisions. Students involved with these projects also gain valuable experience both in the field and the laboratory that will aid them when seeking jobs in the fisheries and management fields. Our students have had the opportunity to present their data to management officials at meetings and through the literature.