| coded wire tag recovery: | Coded wire tags are laser etched metallic wires implanted into the snouts of many hatchery fish. The coding on the tag indicates the hatchery from which the fish was released as well as the year the fish was released. These tags are subsequently recovered and read to create a database of where individual tags were recovered. |
| emigration: | Migration from freshwater to the ocean. |
| escapement: | The number of salmon and steelhead that return to a specific point of measurement after all natural mortality and harvest have occurred. Natural spawning escapement (or spawner escapement) refers to fish that return to spawn without human intervention in rivers, streams or lakes. Hatchery rack escapement refers to hatchery-produced fish that return from the ocean to collection points at the hatchery of origin. |
| exploitation rate: | The total rate of harvest of a given stock or run of fish. |
| habitat: | The environment in which an organism normally lives and grows. Habitat factors of particular relevance to salmon and steelhead include, but are not necessarily limited to, water temperature, flow, instream cover (including large woody debris), substrate, pools, shading, and bank angle and stability. |
| immigration: | Migration from the ocean to freshwater. |
| jack: | Sexually mature male salmon or steelhead that return to freshwater one or more years earlier than is customary for a particular species or stock. |
| juvenile: | Fish from one year of age until sexual maturity. |
| outmigration: | Downstream migration of fish through the river system to the ocean. |
| PIT tags: | Passive Integrated Transponder tags are used for identifying individual salmon for monitoring and research purposes. Each miniaturized tag consists of an integrated microchip that is programmed to include specific fish information. The tag is inserted into the body cavity of the fish and decoded at selected monitoring sites. |
| smolt: | A juvenile salmon or steelhead migrating to the ocean and undergoing physiological changes to adapt its body from a freshwater to a saltwater existence. |
| stock: | The fish spawning in a particular lake, stream, or series of streams at a particular season, which fish to a substantial degree do not interbreed with any group spawning in a different place, or in the same place at a different season. |
| Southern Oscillation Index (SOI): | An oceanographic indicator of environmental conditions that allows for the prediction of global climate events such as El Nino. |
| tailrace: | That portion of a stream immediately downstream of a release from a dam, penstock, or other man-made water discharge device. The area is typically characterized by higher than normal velocity and turbulence. |
| time series: | A sequence of years during which records of a consistent form are collected in order to determine a trend. |
| trend: | The directional change in a time series data set. Population trends identify trends in the abundance of a particular stock, population, or other fish grouping. |
| upwelling: | The movement to the surface of ocean bottom waters in areas near the continental shelf. These waters are typically rich in nutrients. |
| yearling: | One-year-old fish. |
| wild population: | Fish that have completed their entire life cycle in the natural environment and maintained successful natural reproduction with little or no supplementation from hatcheries or other culture facilities. A natural population is similar but may contain fish of hatchery or mixed parentage. |
Revised 03/05/97