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.
Ariidae
Many other species of catfish are also present in freshwater habitats; some species only occur in freshwater. In North and South America, about 43 species extend into brackish water or are found exclusively in fresh water.