What do catadromous fish do?

Catadromous fish are characterized by their unique life cycle in which they migrate from freshwater environments to the ocean to spawn. This reproductive strategy is typically seen in species like the American eel, which lives in freshwater but returns to the saltwater of the Sargasso Sea to reproduce.

This migration is crucial for the reproductive success of catadromous species, as the marine environment provides the necessary conditions for their eggs and larvae to develop. The transition from freshwater to saltwater not only serves as a spawning ground but also allows the fish to exploit different ecological niches at various life stages, enhancing their survival and growth potential.

Other options describe different migratory patterns and habitats that do not fit the definition of catadromous behavior. For example, the choice that states fish migrate from saltwater to freshwater to spawn describes anadromous species, which is fundamentally different from the catadromous lifestyle.