The timing of major life cycle events (reproduction, flowering, feeding) is set by seasonal environmental cues in many organisms. Migratory fish in the Great Lakes are largely spring spawners, and they move into tributary rivers as the water warms in March-June. There is growing evidence that the timing of these migrations is shifting under climate change, creating ever earlier migrations. These changes in timing may profoundly change which species are present in rivers at a given time, potentially unraveling critical ecological linkages during the dynamic spring warming period. We are analyzing historical data on migration timing of six species across the Great Lakes basin, using Bayesian statisical modeling to maximize power to detect shifts from a patchwork of migration records in space and time.
The goals are to: 1) Understand which fish species may have reproductive cycles disrupted by climate warming. 2) Assess whether critical species interactions are eliminated by differential shifts in phenology. 3) Maintain healthy populations of native and introduced migratory fishes to support recreational, subsistence, and commercial fisheries.