| Anadromous | To hatch in freshwater, and migrate to saltwater only to return to have your offspring in freshwater. |
| Anal fin | Provides balance. |
| Adipose fin | There is no known use; however, this fin is often clipped to differentiate hatchery fish from wild fish. |
| Alevin | 2nd stage of the salmon life cycle; newly hatched salmon with the yolk sac still outside its body, doesn’t swim, and lives in the spaces between the gravel. |
| Carcass | 7th and final stage of the salmon life cycle; after spawning salmon die their bodies fertilize the vegetation around the stream. In turn the vegetation helps keep the stream clean and cold providing a healthy habitat. The bugs that eat the carcasses are in turn eaten by the fry of the next generation of salmon. |
| Caudal fin | Also known as the tail fin, it provides the main source of propulsion, females use their caudal fin to dig their redd (nest). |
| Caudal peduncle | The narrow region of the body of a fish just in front of the caudal fin. Provides the muscle to power the caudal fin. |
| Cycloid | Thin fish scale that shows concentric lines of growth, without serrations on the margin. |
| Dorsal fin | Provides steering control and balance. |
| Erosion | To wear (something) by weathering or abrasion such as water flowing over a rock or the exposed dirt on a river bank. |
| Estuary | Tidal mouth of a river, where the stream meets the ocean, it eases the transition from fresh to salt water. |
| Eyed egg | If a salmon egg is fertilized the first part of the salmon you can see growing in the egg is the eye. |
| Fish Eyes | Fish eyes can see both to the left and the right at the same time, and each eye can move independently. |
| Food web | A system of interlocking and interdependent food chains showing who eats whom. |
| Freshet | The flooding of a river from a heavy rain or snow melt. |
| Fry | 3rd stage of the salmon life cycle; when the salmon emerges from the gravel, can swim, no longer has a yolk sac, and has parr marks. |
| Jack | Male salmon that return to spawn after only spending 1 or 2 years in the ocean and as a result are very small. |
| Kype | The hooked jaw many male salmon develops during the spawning phase. |
| Ocean derived nutrients | Nutrients acquired (eaten) by anadromous fish (salmon) out in the ocean and deposited in a freshwater ecosystem when that fish returns to spawn and dies. |
| Ocean Going Adult | 5th stage in the salmon life cycle; salmon leave the estuary and head north to the cold and food filled waters of Alaska for an average of 3-5yrs. |
| Odolith | Small oval calcareous bodies in the inner ear of vertebrates that are involved in sensing gravity and movement. |
| Osmoregulation | The maintenance of constant osmotic pressure in the fluids of an organism through the control of water and salt concentrations. Salmon use their kidneys and gut to excrete the excess salt they accumulate when living in salt water. |
| Parr marks | Dark bars across the body of a fry which helps them camouflage in the shadows of the stream. |
| Redd | Salmon nest made from a female digging in the gravel with her tail. |
| Riparian zone | The interface between land and a river or stream. A healthy riparian zone should be heavily vegetative which helps to filter stormwater sediments and pollutants before the water enters the stream. |
| Roe | Another name for a salmon egg. |
| Salmon egg | Also known as roe, it is the reproductive contribution of the female salmon. |
| Scale | A small plate-like structure that forms the external covering of fishes, and reptiles. Salmon scales are cycloid with concentric rings for determining age. |
| Smolt | 4th stage of the salmon life cycle; when it turns silvery and enters the estuary. |
| Smolting | The transition of changing from a fry to a smolt. |
| Spawn | Release or deposit of eggs. |
| Spawners | 6th stage in the salmon life cycle; adults return from the ocean to their natal streams to spawn. |
| Watershed | An area or region drained by a river, river system, or other body of water. |
| Wetland | Areas that are saturated or covered by water as least part of the year, contain specific types of plants, and have hydric soils (soils formed in water and usually in the absence of oxygen). |
| Yolk sac | A structure which stores nutrients derived from the egg. Young salmon absorb nutrients from this sac while their digestive system matures. |
