Behavioural and genetic assessment of mate choice in brook trout (Salvelinus fontinalis)

A multifaceted approach is necessary in order to better understand the complex processes involved in mate choice. I investigated the mechanisms of mate choice using a population of brook trout (Salvelinus fontinalis ) with known ancestry, using a combination of behavioural observations and microsatellite genetic data to better understand how relatedness influences mate choice in this species. Video observations of female mate choice based on kinship indicated a statistically significant preference of female brook trout for association with males, as demonstrated by the decreased activity level of females in the presence of males. No statistically significant preference for unrelated or related males was evident, however, indicating that while females preferred to be near males, the relatedness of the preferred males varied between individuals. In a second experiment, the roles of relatedness, stocking and local adaptation in mate selection and mating success were investigated by introducing seven brook trout families of known ancestry and relatedness into a semi-wild environment. Reproductive contributions were assessed using two consecutive years of sampling newly hatched fry and determining parentage via microsatellite genotyping. Low levels of reproductive success of the stocked fish, along with little evidence of introgression, suggest that local adaptation is an important (and limiting) component of successful reproduction in this species. These findings are important to future conservation and management of brook trout, as they highlight the importance of maintaining genetic diversity and evolutionary potential both within and between populations.