Health metrics in Lake Ontario salmonines related to thiamine stress in Salmon River stocks.

Session: Thiamine Deficiency in the Great Lakes (1)

Donald Tillitt, U.S. Geological Survey, Columbia Environmental Research Ctr., dtillitt@usgs.gov
Steven Smith, Lynxnet Services, stevensmith@contractor.usgs.gov
Matthew Futia, The College at Brockport - State University of New York, mfuti1@u.brockport.edu
Katie Edwards, Binghamton University / Cornell , kedwards@binghamton.edu
Clifford Kraft, Cornell University, Dept. of Natural Resource, cek7@cornell.edu
Jacques Rinchard, The College at Brockport, State University of New York, jrinchar@brockport.edu

Abstract

Thiamine deficiency complex (TDC) in salmonines has been a primary cause for lack of natural recruitment and declines in certain Great Lakes populations.  Indeed, in both Lake Huron and Lake Michigan, signs of natural recruitment in lake trout have only become evident after average egg concentrations of thiamine increased to above the threshold for fry mortality of 4 nmol/g-egg.  Mortality of individuals within spawning runs of adult steelhead trout (Onchorynchus mykiss) in the Salmon River, Lake Ontario suggested that TDC stress was occurring in these stocks.  Here we report on thiamine-dependent enzyme activity (transketolase) in the brains of four species of salmonines collected in Lake Ontario, in 2016 and 2017.  Nascent enzyme activity and latency were measured to estimate apoenzyme as an indicator of thiamine stress.  These values were also compared to tissue thiamine concentrations.