The overall goal of this collaborative project is to evaluate characteristics of prey biochemistry and predator foraging differences that lead to thiamine deficiency complex TDC in lake trout

This $332,857 federal Project Grant award from the U.S. Fish and Wildlife Service under the Fish and Aquatic Conservation - Aquatic Invasive Species (CFDA 15.608) program will support a collaborative research project to evaluate characteristics of prey biochemistry and predator foraging that contribute to thiamine deficiency complex (TDC) in lake trout populations in the Great Lakes region.

The key objectives of the project are to: 1) compare the nutritional quality of prey fishes in Lakes Ontario and Superior through measurements of thiamine concentrations, lipid content, and thiaminase activity; 2) determine relationships between lake trout diet composition and thiamine concentrations; 3) compare lake trout recruitment potential between the two lakes by measuring egg thiamine concentrations; and 4) evaluate the correlations between proposed TDC mechanisms and the extent of thiamine deficiency in lake trout. The funding will support data collection, analysis, and the development of a database on prey nutritional quality that will be made available to fisheries managers in the Great Lakes region. Deliverables include a final report, conference presentations, and several peer-reviewed journal publications.

Objectives:1 compare nutritional quality of prey items fishes from lakes ontario and superior through measurement of their thiamine concentrations lipid contents and thiaminase activities. 2 determine relationships between lake trout diet composition and thiamine concentrations using diet estimates from stomach contents stable isotope and fatty acid analyses.3 compare lake trout recruitment potential between lakes superior and ontario through measurement of EGG thiamine concentrations.4 evaluate consistency in the correlations between proposed mechanisms of thiamine deficiency and the extent of thiamine deficiency in lake trout. The knowledge gained from this study will help researchers and managers better understand the underlying mechanisms of TDC and predict how prey assemblages could impact TDC and ultimately lake trout recruitment in the great lakes. Deliverables:1. Final report at the conclusion of the study presentations at local national and international conferences e.g. new york american fisheries society international association for great lakes research national american fisheries society.2. Several publications in peerreviewed journals e.g. journal of great lakes research canadian journal of fisheries and aquatic sciences. 3. Through this work we will develop a working database of prey nutritional quality that will be available to fisheries managers from the great lakes region.