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parr marks

Dark, vertical marks on many species of young trout that provide camouflage. These marks can remain on the fish through adulthood in some species such as the golden trout or small resident westslope cutthroat trout.

passive intergrated transponder (pit) tags

A small (11mm), individually coded, electronic tag that is implanted into the body of a fish using a small syringe. This tag is activated by passing a hand-held scanner over the fish, and since it is off until it is activated, it can last for up to 50 years.

pectoral fin

First set of fins behind (anterior) a fish's head. On trout, these fins are located on the ventral side (underside) of the fish. Some fish, such as bass, have them behind their head along the mid-line of their body.

pelvic fin

Posterior-most paired fins on the ventral side of a fish's body.

pH

A measure of the acidity or alkalinity of a solution, numerically equal to 7 for neutral solutions, increasing with increasing alkalinity and decreasing with increasing acidity. The pH scale commonly in use ranges from 0 to 14.

piscivorous

piscivorous means "fish eating". Examples of piscivorous fish include northern pike or bull trout, but their diets also include aquatic insects.

Habitually feeding on fish; fish-eating.

pool

Stream features that is normally deep and wide, slow water with no turbulence.

Scour- A rubbing or scraping motion which causes cleaning or digging.

Scour Pool- A pool created by the scouring action of the stream flowing against an obstruction, such as a log or rock, causing an increase in depth.

Plunge Pool- A pool created by water passing over or through a complete or nearly complete channel obstruction, and dropping steeply into the streambed below scouring out a deeper spot in the stream.

potamodromous

A life history strategy in which a species of fish completes its entire life cycle in freshwater including growing, maturing and spawning. All species in Montana are potamodromous.

preceipitation

Water in the form of rain, snow, sleet or hail that falls to the earth after accumulating in the atmosphere.