Upwelling
The major upwellings in the ocean are associated with the divergence of currents that bring deeper, colder, nutrient rich waters to the surface. There are at least five types of upwelling: coastal upwelling, large-scale wind-driven upwelling in the ocean interior, upwelling associated with eddies, topographically-associated upwelling, and broad-diffusive upwelling in the ocean interior.
Eastern freshwater cod
Eastern freshwater cod originally occurred in great abundance throughout the system, to significant altitudes. Though reportedly "M. ikei" were never found above the large falls in some headwaters, the uppermost reaches of many tributaries feature in this species' range.