Freshwater salmon and saltwater salmon are the same species. In North America, this includes Atlantic salmon, of which there is only one species, and five Pacific salmon species: Coho, Chinook, Pink, Sockeye Salmon, and Pal. However, there are many differences in behavior and physiology between freshwater salmon and saltwater salmon. Some grow larger in salt water, some do not eat when in freshwater rivers, others die after spawning in freshwater, and so on.
All salmon are classified as anadromous, a term derived from Greek words that mean upward (ana) and running (dromos). This refers to fish that spend part of their life in the ocean and move into freshwater rivers or streams to spawn. For example, anadromous fish are born in fresh water, move into salt water to grow to adulthood or sexual maturity, and then return to fresh water to reproduce. When to fish for salmon depends on when it occurs in these different locations.
Atlantic, Koho, and Chinook salmon are the most famous anadromous fish. Others are steelhead, sturgeon, striped bass, herring and shad. There are approximately 100 species of anadromous fish around the world.
Some live entirely in fresh water
Understanding anadromia is made difficult by the fact that some anadromous species have adapted to full life in freshwater environments, either naturally or by introduction. These species, which include freshwater salmon, striped bass, and steelhead, migrate from lakes, where they spend most of their lives, to rivers to spawn. In such cases, these fish originally come from salt water. They remain anadromous when placed in pure fresh water, despite using the lake like the ocean.
Fish that come from saltwater but have freshwater forms are often referred to as “inland waterway”, regardless of whether or not they have a clear path to and from the ocean. Sometimes these fish are physically prevented from reaching the ocean. Fish in a reservoir or lake may not be able to walk. Fish in some streams, such as in high mountain regions, have a free passage to the sea, but cannot return due to obstacles, especially waterfalls.
Sometimes the terminology for the freshwater forms of saltwater fish is confusing. Atlantic salmon, found in freshwater lakes with no access to the sea, is popularly referred to as landlocked salmon or landlocked salmon to differentiate it from the saltwater version. Some people can simply refer to them as freshwater salmon. Sockeye salmon, found in freshwater lakes with no access to the ocean, is often referred to as Kokanee salmon. However, koho and chinook salmon (as well as striped bass and arctic char) are referred to by the same name in saltwater or freshwater, although chinook salmon are sometimes referred to as “king salmon” in freshwater and saltwater.
Regardless of what you call them, keep in mind that you will need a saltwater fishing license if you are going to fish for salmon in saltwater or tidal rivers. If you fish for salmon in freshwater environments, you will need a freshwater fishing license.