As they continue their journey from that Sargasso Sea and move more fully into freshwater, juvenile American eels start to gain pigmentation and turn from translucent “glass eels” into “elvers.” Dams remain a significantly obstacle, greatly reducing their ability to reach freshwater habitat.
Diadromous fish (Greek for “running through”) are those unique species that migrate between fresh and salt water. There are two general types: anadromous fish (“running up”) and catadromous fish (“running down”). The former spend most of their lives in saltwater, but migrate into freshwater to spawn; the later do the opposite.