The diet of historical Lake Ontario Atlantic salmon was composed of lake herring (Coregonus artedi) and bloater (Coregonus hoyi); these prey fishes collapsed the 1950's due to environmental changes and overfishing. After the collapse, introduced alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) composed the diet for Lake Ontario salmonids. Alewife and rainbow smelt are known to contain high levels of thiaminase, whereas lake herring and bloater contain low levels of thiaminase. Thiaminase is an enzyme that breaks down thiamine, a vitamin that is important for energetic and metabolic function.
Is it suggested that some Atlantic salmon populations and individuals may have adaptations to coping with high thiaminase diets
(Dimond and Smitka 2005). The Saint-Mary's River population from Michigan, USA has a diet high in thiaminase (high in alewife) and
has only a small proportion (25-35%) of adult females returning to spawn that display low thiamine levels. This variation in
thiamine levels may suggest behavioural or genetic adaptations.
This study will examine the performance of three candidate populations exposed to historical and current diets of Lake Ontario. Production of diets is in collaboration with Dr. Dominique Bureau and Dr. Patricio Saez. Younger and older salmon performance will be measured by examining behaviours, thiamine levels, reproductive traits, and offspring performance.
Groups of younger (two-year-old) and older (six-year-old) Atlantic salmon will be fed diets varying in thiaminase content. Diets will be fed for two to three years because it may take at least that long to induce a thiamine deficiency.
The data gathered during the experiment are:
Houde ALS, Saez PJ, Wilson CC, Burean DP, Neff BD. 2015. Effects of feeding high dietary thiaminase to sub-adult Atlantic salmon from three populations. Journal of Great Lakes Research 41: 898-906. |PDF|
Brown SB, Honeyfield DC, Hnath JG, Wolgamood M, Marcquenski SV, Fitzsimons JD, Tillitt DE. 2005. Thiamine status in a dult salmonines in the Great Lakes. J Aquat Anim Health 17: 59-64. doi: 10.1577/H04-059.1.
Dimond P, Smitka J. 2005. Evaluation of selected strains of Atlantic salmon as potential candidates for the restoration of Lake Ontario. Trout Unlimited Can Tech Rep ON-012, 41 pp. Available at: http://www.tucanada.org/reports/ON-012_AtlanticSalmonStrains.pdf.
Fisher JP, Brown SB, Wooster GW, Bowser PR. 1998. Maternal blood, egg and larval thiamin levels correlate with larval survival in landlocked Atlantic salmon (Salmo salar). J Nutr 128: 2456-2466. Available at: http://jn.nutrition.org/content/128/12/2456.abstract.