Grant: Discovery Grants Program - Individual

Life history traits directly influence an organism's ability to pass genes to the next generation. Traits like growth rate and maturation age vary widely among- and within-species and affect harvestable yields. Understanding this variation is critical for conservation, management, and insights on adaptation. The long-term objectives of my research program are to determine the scope, hierarchical expression within-species, origins and implications of intra-specific life history variation in fishes. Three short-term objectives are outlined by this proposal. (I) An examination of temporal changes in the life histories of capelin, herring and sand lance will address the significance of environmental perturbation and fishery induced evolution. Similar long-term temporal shifts in these species would indicate widespread mid-trophic alterations, and energy flow changes in the marine ecosystem. The absence of temporal shifts in unexploited sand lance would suggest top-down fishing mortality as a probable cause in other species. (II) Artificial fertilizations will identify local adaptation between on- and off-beach spawning capelin and spring- and autumn-spawning herring. Such genetic variation would be important for productivity and should be protected for long-term viability of species and fisheries. Barriers to fertilization among-populations would also indicate the degree to which a general phenomenon might mitigate human induced genetic homogenization. (III) Environmental effects on growth and survival are reasonably documented, but we know very little on factors influencing fertilization ability. Individual variability in sperm performance will be examined under different environmental conditions for several species. Local adaptation to spawning conditions in populations of cod and capelin will be investigated at different temperatures and salinities. Results of the sperm work will indicate evolutionary trends among-species and genetic differences among-populations that would be important to protect, and may also help improve aquaculture techniques.