Concordia University
M.Sc. candidate
Supervisor: Dylan Fraser
Start: 2010-09-01
End: 2012-08-20

Project

Ecological correlates and long-term consequences of hatchery-wild hybridization
The intentional and unintentional removal of reproductive barriers between populations is resulting in ever increasing occurrences of intraspecific hybridization between genetically distinct populations, in many cases of domestic or hatchery origin. To appropriately manage the potential risks to nearby wild populations such intraspecific hybridization represents conservation and wildlife managers must understand what factors affect the extent of hybridization as well as what the long-term outcomes are for affected populations. This study presents the results of two separate but related investigations into this phenomenon. The first addressed whether environmental or anthropogenic variables can be used to predict the extent of admixture following hybridization between wild and hatchery brook trout populations. The results suggest that populations inhabiting less productive habitats (higher elevation, reduced littoral zones) experience greater admixture following hybridization with hatchery fish, as do populations exposed to increased human activity (elevated fishing pressure and stocking frequencies). The second portion of this study addressed the long-term consequences of hybridization on fitness and adaptability through experimental matched plantings of wild, admixed and hatchery strains into three new environments roughly 360 km away. Results indicated that among the populations studied, there was no evidence for long-term deleterious effects of hybridization after as few as 7 generations following the cessation of stocking. The results of these two studies have implications for the management of hybrid populations and hybridization events following accidental introductions by proposing measures that may limit the resulting amount of admixture as well as for the conservation and restoration of native populations in areas exposed to hybridization with conspecifics as the results suggest that any negative effects of hybridization may be transient, with populations displaying levels of survival and phenotypic plasticity comparable to wild populations in a time span of fewer than ten generations.

Keywords

intraspecific hybridization, introgression, salmonidae, brook trout, hatchery, stocking, salvelinus fontinalis, Conservation

Publications

1- Concurrent habitat and life history influences on effective/census population size ratios in stream-dwelling trout
Belmar-Lucero, Sebastian, Jacquelyn L. A. Wood, Sherylyne Scott, Andrew B. Harbicht, Jeffrey A. Hutchings, Dylan J. Fraser
2012 Ecology and Evolution