Comprehensive Assessment & Monitoring Program (CAMP)

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Glossary of CAMP Terminology

Aerial redd survey

A monitoring method that uses an airplane or helicopter to count the number of redds in a river. Redds are gravel spawning nests. The aerial redd counts are then used to estimate the number of adult salmon that spawn in that river.


Anadromous (uh-nad-ru-mus) fish species are ones that spend most of their lives in the ocean but reproduce in fresh water.

For the purposes of the Central Valley Project Improvement Act (CVPIA), anadromous fish are "...those stocks of salmon (including steelhead), striped bass, sturgeon, and American shad that ascend the Sacramento and San Joaquin rivers and their tributaries and the Sacramento-San Joaquin Delta to reproduce after maturing in San Francisco Bay or the Pacific Ocean."

The Anadromous Fish Restoration Program has determined that in the context of the CVPIA, the use of the term "salmon" refer to four stocks of Chinook salmon which include fall-, late fall-, winter-, and spring-run Chinook salmon.

Anadromous Fish Restoration Program (AFRP)

The program is administered by the U.S. Fish & Wildlife Service. Its goal is to at least double natural, sustainable production of anadromous fish in California's Central Valley on a long-term basis. This program is authorized under Section 3406(b)(1) of the Central Valley Project Improvement Act (CVPIA). Since 1995, the AFRP has helped implement over 195 projects to restore natural production of anadromous fish.


Photo: USFWS

Angler Survey

Also known as a creel census, an angler survey is a monitoring method used to estimate the number of fish harvested by sports anglers.

Carcass Survey

A monitoring method used to estimate the number of adult salmon that spawn in a river. With this technique, recently dead salmon carcasses are collected, colored tags are attached to the carcasses. The tagged carcasses are returned to the river. The ratio of tagged to untagged carcasses which are observed during subsequent surveys is used to develop a fish abundance estimate.

Central Valley Project Improvement Act (CVPIA)

See an overview of the CVPIA. Read the full text of the CVPIA (108 KB PDF).

Fish Screen

One of four CVPIA tools that can be used to promote increases in the natural production of anadromous fish.

A fish screen prevents fish from entering a water diversion structure and reduces the number of fish killed or injured.

Fyke trap

Photo: CDFW

Fyke Trap

A fyke trap consists of a mesh net with a live box that is attached to one end. In smaller streams, a fyke net can be fitted with wing nets that effectively cover all or most of the stream width.

Gill net

Photo: Juergen Geist, CDFW

Gill Net

Mesh nets that are used to collect fish. When fish attempt to pass through a gill net, their gills become entangled in the net.

Habitat Restoration

One of four Central Valley Project Improvement Act tools that can be used to promote increases in the natural production of anadromous fish.

Habitat Restoration activities are designed to increase the production of anadromous fish by improving their natural habitat. For example, adding gravel to a stream or river increases the amount of substrate that Chinook salmon could use for spawning.

Clipping fin of hatchery-raised fish to distinguish it from wild ones.Hatchery Returns

A monitoring method that counts the number of natural and hatchery-produced adult fish entering a fish hatchery.

The number of naturally produced fish that enter hatcheries is added to the estimated number of fish that naturally spawn in a river to estimate the total in-river run for a particular watershed.

Fisheries biologists routinely mark hatchery fish by clipping the adipose fin. The adipose fin is a small fleshy fin on the back, just in front of the caudal (tail) fin. Marking juvenile hatchery fish provides an ability to discriminate between wild (unmarked) and hatchery (marked) fish when surveys of adult fish are made.

Ladder Count

A monitoring method used to estimate in-river spawner abundance. Adult salmon are counted when they pass a fish ladder as they return upstream to spawn. "Fish steps" would be more accurate than "fish ladder." The many steps in the "ladder" provide areas for fish to jump up and deep pools for resting.


Fish are tagged and released. If they are caught again, researchers can learn about fish movement, migration, mortality and growth. The tags also help researchers estimate population size.


Photo: USFWS

Midwater Trawl Survey

A monitoring method that uses a small boat to tow a net, which captures fish in the upper 6 feet of the water column behind the boat.

Ocean Harvest Survey

A monitoring method used by the California Department of Fish & Game, and adapted by CAMP to estimate the number of adult fish harvested in the ocean by sport and commercial fishing.


A gravel spawning nest in a river bed where eggs and sperm are deposited. Young salmon fry stay in the redd, living on stored nutrients, until they are old enough to find their own food.

Rotary Screw Trap

Photo: Harry Mossman, USFWS

Rotary Screw Trap

An in-river fish sampling tool for sampling juvenile fish that are swimming downstream. The trap consist of a six to eight foot funnel suspended between two pontoons. As water enters the funnel, the internal screw core rotates. Fish are trapped in pockets of water that are forced into a box at the rear of the trap.

Snorkel Survey

A monitoring method when divers with snorkels estimate in-river spawner abundance. Divers visually survey adult salmon (normally spring-run Chinook) prior to spawning. This underwater survey method provides an index of fish abundance, not an absolute count.

Structural Modifications

One of four Central Valley Project Improvement Act tools that can be used to promote increases in the natural production of anadromous fish.

Structural modifications result in changes to facilities that impair fish movement patterns, and result in increased opportunities for successful fish passage.

For example, a structural modification may include the installation of a fish ladder that allows adult salmon to move upstream above a dam. Alternatively, a structural modification could also result in the removal of a barrier that prevents small salmon from moving downstream to the Pacific Ocean.

Sturgeon in trammel net

Photo: CDFW

Trammel Net

A trammel net is a variation on the gill net (see above). It consists of three layers of net. A slack, small mesh, inner panel of netting is sandwiched between two outer layers of netting, which are taught and have a larger mesh size.

Trammel nets entangle fish in bags or pockets of netting. This occurs when fish swim through one of the outer panels, they hit the inner panel, and are carried through to the other outer panel, which creates a bag or pocket, thereby trapping the fish.

Water Management Modifications

One of four Central Valley Project Improvement Act tools that can be used to promote increases in the natural production of anadromous fish.

Water management modifications include options that are designed to change the amount, timing, or location of water such that a more favorable aquatic environment is created for anadromous fish. For example additional water could be released from a dam to create more favorable conditions for fish reproduction, rearing, or migration.