Don Pedro ProjectSalmonid Information Integration and Synthesis Study
Salmonid Information Integration and Synthesis Study (W&AR-5)
Draft Glossary
TermsDefinitions
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 finThe 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-dependentFactors affecting the population that are dependent on the population size, such as spawning habitat area or juvenile rearing area at higher population sizes.
DensityIndependenceFactors affecting the population regardless of population size, such as temperature, disease, or stranding.
DeltaAn 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 east of where the rivers enter SuisunBay (an upper arm of San FranciscoBay).
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-stageTemporal 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.
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 bodythat 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.
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 fry-to-juvenile step.
WildSalmon 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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