Don Pedro Project
Salmonid Information Integration and Synthesis Study
Salmonid Information Integration and Synthesis Study (W&AR-5)
Draft Glossary
Terms
Definitions
Adipose fin
A small fleshy fin with no rays, located between the dorsal and caudal
fins. Clipping of adipose fins is used to identify hatchery-raised
salmonids.
Age
The number of years of life completed, here indicated by an arabic
numeral, followed by a plus sign if there is any possibility of
ambiguity (e.g., age 1, age 1+).
Age composition
Proportion of individuals of different ages in a stock or in the catches.
Age-class
A group of individuals of a certain species that have the same age.
Alevin
Newly hatched salmon or steelhead that have not completely absorbed
their yolk sacs and usually have not yet emerged from the gravel.
Alluvial
Originating from the transport and deposition of sediment by running
water.
Anadromous
Fish such as salmon and steelhead trout that migrate up rivers from the
sea to spawn in fresh water.
Caudal fin
The tail fin.
Coded-wire tag (CWT)
A small (0.25mm diameter x 1 mm length) wire etched with a
distinctive binary code and implanted in the snout of salmon or
steelhead, which, when retrieved, allows for the identification of the
origin of the fish bearing the tag.
Cohort
Members of a life-stage that were spawned in the same year.
Density-dependent
Factors affecting the population that are dependent on the population
size, such as spawning habitat area or juvenile rearing area at higher
population sizes.
Density Independence
Factors affecting the population regardless of population size, such as
temperature, disease, or stranding.
Delta
An alluvial landform composed of sediment at a river mouth that is
shaped by river discharge, sediment load, tidal energy, land
subsidence, and sea-level changes. The Sacramento and San Joaquin
River Delta is formed at the western edge of the Central Valley by the
confluence of these rivers and refers to a complex network of channels
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Salmonid Information Integration and Synthesis Study
east of where the rivers enter Suisun Bay (an upper arm of San
Francisco Bay).
Escapement
The number of sexually mature adult salmon or steelhead that
successfully pass through an ocean fishery to reach the spawning
grounds. This amount reflects losses resulting from harvest, and does
not reflect natural mortality, typically partitioned between enroute and
pre-spawning mortality. Thus, escaped fish do not necessarily spawn
successfully.
El Niño
A climactic event that begins as a warming episode in the tropical
Pacific zone that can result in large scale intrusions of anomalously
warm marine water northward along the Pacific coastline of North
America.
Estuary
A region where salt water from the ocean is mixed with fresh water
from a river or stream (also see Delta).
Floodplain
The part of a river valley composed of unconsolidated river deposits
that periodically floods. Sediment is deposited on the floodplain during
floods and through the lateral migration of the river channel across the
floodplain.
Fry
Salmonid life stage between the alevin and parr stages.
Homing
The ability of a salmon or steelhead to correctly identify and return to
their natal stream, following maturation at sea.
Hydroelectric
Generation of electricity by conversion of the energy of running water
into electric power.
Irrigation
To application of water to land by means of pumps, pipes, and ditches
in order to help crops grow.
Kelts
A spent or exhausted salmon or steelhead after spawning. All species
of Pacific salmon, except some steelhead and sea-run cutthroat, die at
this stage.
Life history
The events that make up the life cycle of an animal including
migration, spawning, incubation, and rearing. There is typically a
diversity of life history patterns both within and between populations.
Life history can refer to one such pattern, or collectively refer to a
stylized description of the 'typical' life history of a population.
Life-stage
Temporal stages (or intervals) of a fish’s life that have distinct
anatomical, physiological, and/or functional characteristics that
contribute to potential differences in use of the environment.
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Salmonid Information Integration and Synthesis Study
Macroinvertebrate
Invertebrates visible to the naked eye, such as insect larvae and
crayfish.
Osmoregulation
Refers to the physical changes that take place in salmonids as their
gills and kidneys adjust from fresh water to salt water as they enter the
ocean, and from salt water to fresh water upon their return.
Parr
Life stage of salmon or steelhead between the fry and smolt stages. At
this stage, juvenile fish have distinctive vertical parr marks and are
actively feeding in fresh water.
Predator
An animal which feeds on other living animals.
Production
Output from a stock-production model at a particular life-step.
Recruitment
Addition of new fish to a defined life history stage by growth from
among smaller size categories. Often used in context of management,
where the stage is the point where individuals become vulnerable to
fishing gear.
Redd
A nest of fish eggs consisting of gravel, typically formed by digging
motion performed by an adult female salmon or steelhead trout.
Riffle
A shallow gravel area of a stream that is characterized by increased
velocities and gradients, and is the predominant stream area used by
salmonids for spawning.
Riparian
Referring to the transition area between aquatic and terrestrial
ecosystems. The riparian zone includes the channel migration zone and
the vegetation directly adjacent to the water body that influence
channel habitat through alteration of microclimate or input of LWD.
River mile
A statute mile measured along the center line of a river. River mile
measurements start at the stream mouth (RM 0.0).
Riverine
Referring to the entire river network, including tributaries, side
channels, sloughs, intermittent streams, etc.
Smolt
Salmonid life stage between the parr and adult stages. At this stage,
juvenile salmon and steelhead undergo physical changes and migrate
to the ocean.
Smoltification
Refers to the changes that take place in salmonids as they prepare to
enter the ocean. These changes include the development of the silver
color of adults and a tolerance for salt water.
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Salmonid Information Integration and Synthesis Study
Spawn
The act of producing a new generation of fish. The female digs a redd
in the river bottom and deposits her eggs into it. The male then covers
the eggs with milt to fertilize them.
Spawning grounds
Areas where fish spawn.
Straying
A natural phenomena of adult spawners not returning to their natal
stream, but entering and spawning in some other stream.
Stock
Input value required by the stock-production models. It is the first
required value entered into the population dynamics model
spreadsheets; for example, stock would be the number of fry, for a fryto-juvenile step.
Wild
Salmon or steelhead produced by natural spawning in fish habitat from
parents that were spawned and reared in fish habitat.
Woody debris
Logs, branches, or sticks that fall or hang into rivers. This debris gives
salmonids places to hide and provides food for insects and plants
which these fish feed upon.
Yolk sac
A small sac connected to alevin which provides them with protein,
sugar, minerals, and vitamins. Alevin live on the yolk sac for a month
or so before emerging from the gravel and beginning to hunt food for
themselves.
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