**ABSTRACT NOT FOR CITATION WITHOUT AUTHOR PERMISSION. The title, authors, and abstract for this completion report are provided below.  For a copy of the full completion report, please contact the author via e-mail at m.c.hale@tcu.edu or via telephone at 817-257-8707. Questions? Contact the GLFC via email at frp@glfc.org or via telephone at 734-662-3209.**


Behavioral and genetic diversity among ecotypes of Lake Superior Brook Trout

 Matthew C. Hale1, Krista M. Nichols2, Robert McLaughlin3, Chris Wilson4 and Robert Mackereth5


1Department of Biology, Texas Christian University, 2800 S. University Drive, Fort Worth, TX,

USA 76129


2Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries

Service, NOAA, 2725 Montlake Blvd E, Seattle, WA, USA 98112


3Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G2W1


4Aquatic Biodiversity and Conservation Unit, Ontario Ministry of Natural Resources, Trent

University, Peterborough, ON, Canada K9J 7B8


5Department of Biology, Lakehead University, Thunder Bay, ON, Canada P7B 5E1



June 2017




The main goal of the funded project was to evaluate behavioral and genetic variability between different ecotypes of Brook Trout from Lake Superior. This goal was approached from different angles: 1) by determining the heritability of behaviors such as the propensity to disperse, risk taking, general activity, and aggressiveness, which are potentially connected to the development of different ecotypes in Brook Trout (objective 1), and 2) by using genomic approaches to A) identify genetic polymorphisms associated with the different migratory types (objective 2), and B) to evaluate differential gene expression in the brain between behavioral types (objective 3). In all objectives, wild-caught Brook Trout in Nipigon Bay and tributaries exhibiting alternative life histories -- either adfluvial ‘coaster’ or residents -- were collected for our objectives. Heritability and gene expression for behaviors were evaluated in controlled crosses made between and within life history types, maintained at the Codrington Fisheries Research Facility for several years. Behavioral research suggested repeatable differences in the expression of several behaviors that can broadly be classed as “shy” and “bold”. Several of these behaviors were found to have a strong heritable component suggesting that there is underlying genetic variation for variation in behavior, but our research failed to find an association between parent life history and behaviors expressed by their offspring (objective 1). Evaluation of gene expression in the brains of these offspring identified a small number of genes differentially expressed between shy and bold individuals at ages 1 and 2 postfertilization; the genes differentially expressed between these behavioral types were not genes identified a priori for an association with behavioral diversity, but illustrate the power of a whole-transcriptome approach in the identification of genes and biological process underlying complex behaviors (objective 3). Finally, in wild-caught coaster and resident Brook Trout from Nipigon Bay and tributaries, we failed to find a consistent association in the genome with life history type (objective 2); however, this work, leveraging samples and associated metadata collected under prior funding, did reveal that Brook Trout captured in the Nipigon Bay were almost exclusively from the Cypress River, among the major tributaries sampled. The findings under these joint objectives show that there is genetic diversity and gene expression differences underlying complex behaviors; however, parent life history was not a significant predictor of these behaviors in a common environment. Moreover, these results together with our association analysis in wild-caught individuals, further suggest that life history decisions in these Brook Trout populations are likely promoted by ecological and growth processes operating in each tributary during development.