Note to Teachers: Consider which of these terms you would like your class to commit to memory, and create a “short list” of this glossary for your students.

adaptation: Adjustment or modification of an organism to changes in the environment.
adipose fin: A small fatty fin found on the top back of salmon and trout between the dorsal fin and the tail (caudal fin). This fin is removed (clipped) from Washington state hatchery chinook, coho and steelhead to distinguish hatchery fish from wild fish.
aerate: Supplying with oxygen; with water it is a process of exposing water to the air, usually by churning or breaking the surface of the water, such as waterfalls, riffles, etc..
alevin: Newly hatched fish with yolk sac attached. See sac fry.
algae: Simple plants that grow in water. They range from microscopic size to plant hundreds of feet long.
anadromous: Migratory. A fish that spawns in fresh water then migrates to the ocean, returning to fresh water as an adult to spawn. (From the Greek words for “up river”)
anal fin: Fin located on the bottom and near the back of the fish.
anglers: People who fish. Usually refers to recreational (sport) fishers using a rod and reel.
anthropologist: A person who studies human beings and human cultures.
aquatic: Water-related. Anything that lives in the water.
bar: The area at the mouth of a river where sediments are deposited.
barrier: Barricade; separator; blockage of a route.
Benthic: Bottom-dwelling.
brood fish/brood stock: Fish held in the hatchery to produce eggs like one would raise chickens for eggs.
buck: A male fish.
carbon dioxide: A gas (like oxygen is a gas) which is exhaled from animals and absorbed by plants.
carcass: Body of a dead animal; corpse; carrion.
carrying capacity: The number of fish or wildlife that can be supported by a given area of land or water.
cascades: A steep series of small waterfalls. It is the name given to the mountain range that runs through the center of Washington and Oregon.
caudal fin: Another name for the tail of a fish.
char: A genus of small-scaled trout (Salvelinus).
commercial fishing: Fishing to sell the catch of fish for the market.
counter-shaded: Offset coloration allowing an animal to hide in its environment. Fish usually have darker tops and lighter bottoms, making it difficult to see them from above or below.
divide: The line that separates watersheds, usually a ridgetop.
domestication: To adapt an animal to life in association with humans.
dorsal fin: Dorsal means top. This is the large fin on the top of a fish’s back.
ecological: How plants, animals and other living creatures interrelate to their environment.
ecology: The relationship or study of the relationship of a fish or animal to its environment.
eddy: A current of water (also could be air) which runs against the main current.
electromagnetic signals: Small electrical charges based on magnetic properties.
Endangered Species Act: A law that requires special protection for plant and animal populations that are in danger of becoming extinct.
estuary: The area where the tides of the ocean meet a river current.
environment: The total of all the things around you, both physical and biological.
erosion: The natural process of moving soil and rock material from any part of the earth’s surface.
evaporate: Change from a liquid to a gas.
exploitation: Take for personal use without providing a benefit in return.
extinction: Gone forever.
eyed egg: A fish egg that has developed to the point where the dark eyes of the embryo can be seen through the shell.
fertile: An egg that has the potential to develop and hatch or an animal or fish that can produce
fertilize: Mix sperm and eggs. One sperm unites with (fertilizes) one egg to create a complete set of genetic instructions (genes).
fingerling: A small fish, up to one year of age. A small fish about the size of your little finger. A stage or size measurement in the growth of a fish.
foliage: Plants.
food chain: A chain or series of plants and animals where some feed on certain ones and are in tum eaten by others.
forb: A herbaceous plant other than grass growing on a field or meadow.
freshets: A stream created by overflow or runoff.
fry: Recently hatched fish, after yolk sac has been absorbed, and prior to the fingerling stage.
fungus: A type of lower plant (such as mold) that helps decompose organic matter.
gene: The unit of genetic information passed along from generation to generation through mating.
gills: The feathery organs of fish and other aquatic creatures that extract oxygen from the water and return carbon dioxide.
gillnets: Nets that capture fish as they try to swim through the mesh of the net. Used mostly by commercial fishers.
gradient: Gradual change in coloration, slope, or pressure.
grading: The process of sorting fish by size.
ground water: Water that is contained in the soil or ground which feeds rivers and lakes during low rainfall, and is pumped out of wells.
habitat: The place where a fish or animal lives. It must include the necessary food, water, and shelter.
habitation: Occupancy; residence; moving in.
hatchery: Facility for raising fish.
heath tray: Tray used in hatcheries to raise eggs to the fry stage.
hen: Female fish.
homing: Ability to return or locate “home,” or a desired location.
hydroelectric facility: A dam; a place where electricity is made by falling water.
ice age: A period in geologic time, more than 10,000 years ago, when nearly one quarter of the earth was covered with ice.
imprinting: Behavior in which the first response to a particular stimulus, early in life, becomes a fixed response to the same stimulus thereafter.
incubator: A human-made environment where eggs are placed to hatch.
incubation: The entire process of hatching an egg.
inorganic: Made from material that is not from an animal or plant
interspace: The areas on a fish between the parr marks.
invertebrate: Does not have a backbone.
juvenile: A young fish or animal that is not mature.
larvae: An immature stage of development in many kinds of organisms.
lateral habitat: The calm water areas along the edges of a stream.
lateral line: A sensitive line along the side of a fish which senses changes in pressure.
leaf litter: Old fallen decaying leaves.
liberation truck: The specially equipped tanker truck that hauls fish to the place they will be stocked.
life cycle: The stages of development from egg to adult.
limiting factor: Factors that reduce the populations of living organisms.
marked fish: A fish that has had a fin clipped off, a dye sprayed on, a tag attached, or a wire implanted so it can be identified at a later date.
mash: Food pellets fed to young fish at the hatchery.
maxillary: The upper jaw bone of vertebrates, including fish.
midge: The larval form of any two-winged fly.
migration: Traveling between seasonal habitats.
milt: A milky liquid from the male fish that contains sperm.
Miocene: The geologic time period between 12 million and 25 million years ago.
mortality: Death.
niche: The role that a fish or animal plays in the plant and animal community. The type of habitat it uses.
nutrients: Natural particles which are used by living organisms.
organic: Of plant or animal origin.
parasite: A plant or animal living in or off of another plant or animal, in a harmful way.
parr marks:Vertical lines on young fish which make them harder to see.
pectoral fin: Front steering fins on either side of a fish; corresponds to front legs.
pelvic fin: Lower fin on either side of a fish; corresponds to hind legs.
percolation: To trickle/flow through something.
pesticide: A substance that is poisonous to certain animals considered by humans to be pests.
physiological: Having to do with what goes on inside of a body.
plankton: A tiny animal or plant which floats in water.
pool: A still/calm place of water.
porous: Full of holes and allows liquid to pass through.
predator: An animal that eats another animal.
raceway: A rectangular hatchery pond where water enters at one end and leaves at the other.
rapid: Fast moving, churning water.
ray: The main supporting structures for fins of a fish, usually easy to see and count.
rearing: To raise young.
redd: The nest made by salmonids for their eggs.
reservoir: Storage place for water.
respiration: The process of getting oxygen into the blood, either from the air or water. Another word for breathing.
riffle: Fast, shallow waters of a stream.
riparian zone: The vegetated area next to a stream/ river.
run: A population of fish that returns from the ocean at about the same time headed for the same place.
run-off: Excess water beyond the normal flow of a stream.
salmonid: Any fish of the salmon or trout group.
sediment: Fine particles of rock and sand that collect along a river bottom.
seine: A net weighted at the bottom that hangs vertically in the water and catches fish when its ends are drawn together.
shelter: Cover. A place to hide, raise the young, or get protection from weather or predators.
silt: Tiny, fine particles, such as soil or sand, suspended in and deposited by water.
slime layer: The layer of mucous covering a fish that protects it from fungi, parasites, and disease.
smolt: A young salmon or trout that has turned a silvery color and is ready to migrate to the ocean.
spawn: The act of egg-laying by the female fish and fertilization
by the male fish.
species: A specific type of animal or plant that can breed and produce offspring only with its own kind.
sperm or milt: Milky substance produced by the male fish to fertilize eggs.
stocking: The process of releasing fish into a lake or stream.
storm drain: Drains from streets and parking lots that channel rain water directly into streams.
stream velocity: The speed with which a stream flows.
streamline: A torpedo like shape that moves easily through the water.
substrate: Bottom material.
terrestrial: Belonging to the earth.
transpiration: An animal or plant giving off a watery vapor.
tributary: A side stream that joins a larger river.
turbulence: Uneven rough flow.
vent: The tube with which the female fish deposits her eggs.
watershed: The land area where water collects and flows.
weir: A fence or enclosure set in a waterway for capturing fish. Also, a dam or obstruction in a stream to raise the water level or divert its flow.
yolk sac: Sack attached to a newly hatched fish containing a balanced diet for its early growth.
zooplankton: Microscopic and other very small animals in water, many of which are larval forms.