Oncorhynchus nerka and Salmon

Oncorhynchus nerka noun - Small salmon with red flesh; found in rivers and tributaries of the northern Pacific and valued as food; adults die after spawning.

Salmon and Oncorhynchus nerka are semantically related. In some cases you can use "Salmon" instead a noun phrase "Oncorhynchus nerka".

Salmon noun - Any of various large food and game fishes of northern waters; usually migrate from salt to fresh water to spawn.

Oncorhynchus nerka and salmon are semantically related. Sometimes you can replace phrase "Oncorhynchus nerka" with "Salmon", this terms are similar.