Recovery Goals

Population Goals	Federal Status (Listing Date)	References	Notes

Population History

Escapement

Stock Status Rating Data

Population Details

Additional Information:

Interactive mapping can be found at Salmonscape.

For additional information contact the local biologist, ()

Escapement data last updated

Note: Some information may be preliminary and revised in the future.

Hatcheries associated with this population

Marblemount Hatchery

Escapement Graph Terms ↑

ESU - Evolutionarily Significant Unit: A population or group of populations of salmon considered distinct for purposes of conservation under the ESA based on genetic differentiation and evolutionary significance.

DPS - Distinct Population Segment: A population grouping, roughly synonymous with ESU, which is applied to steelhead and bull trout.

MPG - Major Population Group: groups of populations within ESUs or DPSs that are ecologically or genetically differentiated, but which retain some degree of connectivity greater than that between ESUs and DPSs.

Escapement Fish - A count of fish of a specific stock made at any point along their spawning migration route that is not on the spawning grounds during the spawning season. This amount reflects losses resulting from harvest and natural mortality prior to enumeration but does not reflect pre-spawning mortality. Escaped fish do not necessarily reach the spawning grounds or spawn successfully. If jacks or juveniles are included this needs to be noted in the comments.

Spawner Fish - Live and\or dead fish counted on the spawning grounds during the spawning season. If jacks are included this needs to be noted in the comments.

Spawner Redds - Redds counted on the spawning grounds during the spawning season.

Survival Fish - The estimated survival rate from one life history stage to a second stage, expressed as a proportion (e.g., an average of 50 smolts are produced by each female spawner = 50 smolts/female). The two life history stages being compared must be noted in the Comments field.

Stock Goal Terms

Critical Abundance Threshold Abundance threshold below which a population is at relatively high risk of extinction from: 1) pressures on the breeding population, 2) genetic effects of inbreeding depression or fixation of deleterious mutations, 3) demographic makeup, or 4) uncertainty in status evaluations. When this threshold is reached a common management action is to stop all fisheries on the stock.

Critical ER ceiling A fishery catch limitation calculated as the total mortality caused by a fishery or aggregate of fisheries divided by the sum of total mortality plus escapement. Once escapement falls near or below a critial escapement level (low abundance threshold) Southern U.S. fisheries on the stock are managed to not exceed this ceiling (Ref 2)²⁷

Escapement Goal (EG) The desired number of spawners reaching the spawning grounds.

Exploitation Rate (ER) Total mortality in a fishery or aggregate of fisheries expressed as the proportion of the sum of total mortality plus escapement (Ref 2)²⁷.

Rebuilding Exploitation Rates (RER) The rebuilding exploitation rate (RER) is the highest allowable (--ceiling--) exploitation rate for a population under recovery given current habitat conditions, which define the current productivity and capacity of the population. This rate is designed to meet the objective that, compared to a hypothetical situation of zero harvest impact, the impact of harvest under this plan will not significantly impede the opportunity for the population to grow towards the recovery goal. (See 2010 PS Chinook Harvest Management Plan)

Low abundance threshold A spawning escapement level, set intentionally above the of biological instability, which triggers extraordinary fisheries conservation measures to minimize fishery related impacts and increase spawning escapement (Ref 2)²⁷.

Maximum rebuilding exploitation rate A ceiling RER under normal conditions of stock abundance. This value is further reduced if any component of a management unit falls below its low abundance threshold (see Critical ER ceiling) (Ref 2)²⁷.

Recovery goal Desired spawner abundance interpolated from current, viable, and potential levels (Ref 1)²⁶. "Viable" indicates a low risk of extinction (95% chance of persistence over 100 years) while "potential" indicates that the population is maximally productive under recovered environmental conditions.

Southern U.S. (SUS) Fisheries U.S. salmon fisheries, both marine and freshwater, occurring offshore of or within the states of Washington, Oregon, Idaho, and California.

Upper management threshold An upper escapement level that serves as the threshold for determining whether a management unit has a harvestable surplus of fish (i.e., above this level there is a surplus). This is the escapement level associated with optimum productivity unless otherwise agreed to (Ref 2)²⁷.

Disclaimer

There are several circumstances that complicate the [stock status] rating process. When a wild stock experiences an extremely low survival, it is sometimes difficult to know if that survival is within the normal range for the stock, or if it is entering a depressed state caused by human impacts (e.g., habitat destruction or over-fishing). Naturally-produced salmonid stocks exhibit wide variations in survival, caused in part by changes in freshwater stream flows (droughts and flooding), ocean conditions and biological interactions such as competition and predation (Cooper and Johnson 1992). It is not uncommon for wild stocks to experience one or two extremely low-survival years each decade, resulting in low adult returns. Similarly, natural variation also provides years of above-average production.

Some stocks are experiencing survivals that are so low that they are clearly below the level of natural variation. The survivals of other stocks are intermediate between obviously healthy stocks and clearly depressed stocks and are the most challenging to evaluate because they could be experiencing low survivals within the normal range for the stock. Short-term databases often exacerbate the rating problem because with only a few years of observation it is unlikely that the lowest natural survivals have been documented. The evaluation of most stocks with intermediate survivals was based on the collective judgement of technical agency and tribal staff members most familiar with each stock.

The possibility of survival rate cycles for various stocks also can create difficulty in rating stock status. These cycles may be associated with weather-related impacts on freshwater spawning and rearing success, or even genetically controlled cyclic productivity conditions. The apparent existence of cycles in survival and production data may complicate the task of identifying depleted stocks, since poor stock performance could be the result of natural cyclic variation. Wherever possible, the existence of survival cycles is considered during the stock evaluation process.