Comprehensive Management Plan for Puget Sound Chinook: Harvest Management Component (2017)

This Harvest Management Plan will guide the Washington co-managers in planning annual harvest regimes, as they affect listed Puget Sound Chinook salmon, for management years 2019-2020 through 2028-2029. Harvest regimes will be developed to achieve stated objectives (i.e., total or Southern U.S. exploitation rate ceilings, and / or abundance thresholds) for each of fifteen management units. This Plan describes how these guidelines are applied to annual harvest planning.

The Plan guides the implementation of fisheries in Washington, under the co-managers' jurisdiction, but also considers harvest impacts of other fisheries that impact Puget Sound Chinook, including those in Alaska and British Columbia, to assure that conservation objectives for Puget Sound management units are achieved. Accounting total fishery-related mortality includes incidental harvest in fisheries directed at other salmon species, and non-landed mortality.

The fundamental intent of the Plan is to enable harvest of strong, productive stocks of Chinook, and other salmon species, and to minimize harvest of weak or critically depressed Chinook stocks. Providing adequate conservation of weak stocks will necessitate foregoing some harvestable surplus of stronger stocks.

The Exploitation Rate (ER) ceilings stated for each management unit (Table 4-1) are not target rates. Pre-season fishery planning will develop a fishing regime that does not exceed the ER ceilings for each management unit. Projected exploitation rates that emerge from pre-season planning will, for many management units, be lower than their respective ceiling rates. While populations are rebuilding, annual harvest objectives will be intentionally conservative, even for relatively strong and productive populations.

To further protect populations, low abundance thresholds (Table 4-1) are set well above the critical level associated with demographic instability or with loss of genetic integrity. If escapement is projected to below this threshold, harvest impacts will be further constrained, by lower Critical Exploitation Rate ceilings, to increase escapement. Additionally, for some management units in the Plan, a Point of Instability (or Lower bound) has been defined which requires further harvest constraints below the Critical Exploitation Rates to be developed, based on co-manager agreement.

Exploitation rate ceilings for some management units are based on estimates of recent productivity for component populations. Productivity estimates (i.e., recruitment and survival) are subject to uncertainty and bias, and harvest management is subject to imprecision. The derivation of ER ceilings considers specifically these sources of uncertainty and error, and manages the consequent risk that harvest rates will exceed appropriate levels. The productivity of each management unit will be periodically re-assessed, and harvest objectives modified as necessary.

Criteria for exemption of state / tribal resource management plans from prohibition of the 'take' of listed species, are contained under Limits 4 and 6 of the salmon 4(d) Rule (50 CFR 223:42476). The 4(d) criteria state that harvest should not impede the recovery of populations whose abundance exceeds their critical threshold, and that populations with critically low abundance should be guarded against further declines, such that harvest will not significantly reduce the likelihood of survival and recovery of the ESU.

The abundance and productivity of all Puget Sound Chinook populations is constrained by habitat conditions. Recovery to substantially higher abundance is primarily dependent on restoration of habitat function. Therefore, the harvest limits established by this Plan must be complemented by the other elements of the Comprehensive Recovery Plan that address degraded habitat and management of hatchery programs.