Scott Pavey, PhD-student at the Simon Fraser University, British Columbia, Canada, will give a talk for all those interested on Wednesday 11 April, 11.00-12.00, in Håkonshallen, Animal Science Building, UMB.
Scott Pavey |
The first part of this study challenges recent hypotheses about sockeye salmon colonization based on life history and broadens the pathways that investigators should consider when studying sockeye colonization of novel habitats. Most sockeye populations exhibit lake-type life histories. Riverine populations are thought to be more likely to stray from their natal stream to spawn and therefore colonize new habitat. We examined genetic relationships among five geographically proximate sockeye populations
Length measurements of sockeye salmon |
from the Aniakchak region of the Alaska Peninsula, Alaska. Specifically, we sought to determine if the genetic population structure was consistent with the hypothesis that a riverine population colonized a recently available upriver volcanic caldera lake. Patterns of genetic divergence suggested that the geographically proximate riverine sockeye population did not colonize the lake; the caldera populations were more genetically divergent from the downstream riverine population (Fst=0.047) than a lake-type population in a different drainage (Fst=0.018).
Scott Pavey and colleagues - downstream a river |
The second part of this research involves rapid population divergence. Ecological speciation is the evolution of reproductive isolation resulting from divergent natural selective regimes, and is a key component of adaptive radiation thought to be responsible for much of the biotic diversity of life. This study on sockeye salmon combines genetic, paleolimnetic, geologic, and ecological evidence to describe a case of local adaptation and reproductive isolation in a recently colonized volcanic lake. The parapatric anadromous populations spawn in ecologically different habitats in a lake that resides in a volcanic caldera. Preliminary data suggest the caldera was colonized by a single source and evolved significant reproductive isolation (Fst = 0.011 p<0.001) in less than 100 generations and these populations may be in the incipient stages of ecological speciation.
