Joint Chinook Technical Committee. 1992 Annual Report. TCCHINOOK (93)-2. November 19, 1993.

The Pacific Salmon Treaty established a system of fishery-specific catch and harvest-rate restrictions intended to:

"halt the decline in spawning escapements of depressed stocks; and attain by 1998, escapement goals established in order to restore production of naturally spawning chinook stocks, as represented by indicator stocks identified by the Parties, based on a rebuilding program begun in 1984".

The goal of the program is to rebuild depressed naturally-spawning stocks and restore production through progressive increases in spawning escapements achieved through a combination of catch ceilings in selected mixed-stock fisheries and harvest rate restrictions in nonceiling, passthrough fisheries. The Pacific Salmon Commission instructed the Chinook Technical Committee (CTC) to "develop procedures to evaluate progress in the rebuilding of naturally spawning chinook stocks". The February 1987 Chinook Technical Committee Report, "Assessing Progress Toward Rebuilding Depressed Chinook Stocks", established an evaluation framework that documented an indicator stock program, identified information requirements, and recommended analytical procedures for the assessment of rebuilding. The Committee also identified a number of policy issues that had to be resolved before final conclusions could be reached regarding the status of rebuilding on a regional or coastwide basis. Agreement on those issues has not yet been reached.

In assessing the status of individual stocks under the rebuilding program, the Committee identified three main elements that must be examined: 1) spawning escapement levels; 2) fishery harvest and stock-specific exploitation rates; and 3) production responses to increases in spawning escapements. The Committee recommended that rebuilding assessment be stratified into three phases corresponding with three five-year chinook life-cycles in the rebuilding period: 1984-1988; 1989-1993; and 1994-1998. The Committee felt that a three-phase approach to assessment would address the problems of changing data availability and quality over time.

This report provides an evaluation through the midpoint of the second phase of the rebuilding program using data through 1992. This report includes recent catch in fisheries of concern to the Pacific Salmon Commission (Chapter 1), assessment of spawning escapements for 4₂ escapement indicator stocks (Chapter 2), fishery-harvest and stock-specific-exploitation rates based on 40 exploitation rate indicator stocks (Chapter 3), a summary of the Chinook Model assessment (Chapter 4), and an integration of results from Chapters 2-4 (Chapter 5).

RECOMMENDATIONS

Stock Status and Fishery Regimes

With, at most, five years remaining before the target date of rebuilding for chinook stocks, and 50% of the escapement indicator stocks classified as either Probably Not Rebuilding or Not Rebuilding, the CTC concludes that not all stocks will rebuild by the target date with the current management regime. Recent reductions in survival rates and reduced contributions from major stock groups will likely reduce the rate of rebuilding of natural stocks in the coming years, unless adjustments to management regimes are made. The CTC recommends that the Parties:

1) Define the objectives of the chinook rebuilding program for the five years remaining before the target rebuilding date of 1998. These objectives should include specification of criteria for evaluation of rebuilding:

a) the set of indicator stocks that are to be rebuilt by 1998; and

b) management objectives and constrains (e.g., target harvest rates, minimum catch levels) for particular fisheries.

2) Consider alternatives to fixed quotas for controlling harvest rates. The wide fluctuation in chinook abundance suggest that required reductions in harvest rates will be difficult to achieve with fixed catch quotas. Alternatives include the use of catch levels linked to production of chinook abundance obtained from the chinook model and/or methods which can effectively control harvest rates through fishing effort limitations.

3) Reduce incidental fishing mortality or set allowable harvests based on total mortality. Reductions in stock exploitation rates for reported catch have been offset to a significant extent by increases in incidental mortality.

4) Evaluate the potential for actions which compliment harvest controls, including enhancement and the reduction of nonfishing related sources of mortality. The severely depressed status of some stocks, and the lack of a positive response in escapements, suggest that stock specific actions may be necessary, in addition to the control of harvests in mixed stock fisheries, to rebuild some stocks.

Given well defined objectives, the CTC can work with the Chinook Work Group to develop an appropriate management regime. However, in the absence of new objectives for the rebuilding program, or the clarification of the passthrough provision, the CTC recommends that the Parties:

5) Manage ceiling fisheries so as to achieve, at a minimum, the 1985 target harvest rate reductions for total mortalities. Given the current status of the escapement indicator stocks, these harvest rate reductions remain useful as initial targets.

6) Evaluate compliance with the passthrough provision using the CTC Nonceiling Index. The CTC recommended index for the evaluation of exploitation rates on depressed stocks in nonceiling fisheries provides a technically feasible approach for evaluating compliance with the passthrough provision. Any definition of passthrough which may ultimately be adopted by the PSC must be technically measurable to determine compliance.

Monitoring and Evaluation

1) Eliminate data limitations which are comprising the ability of the CTC to complete the escapement and exploitation rate assessment. General research needs of the CTC have been addressed in detail by the CTC (1992b). Data needs for the annual report, that have not been completely satisfied, include the following:

a) Report estimated CWT recoveries to the Pacific States Marine Fisheries Commission (PSMFC) by July of the year following the fishery. As requested by the PSC, the CTC is currently conducting the Exploitation Rate Assessment on a year-out basis to allow agencies sufficient time to collect and report recovery data. However, the following data were still not available from the PSMFC: i) Estimated recoveries for the 1992 Puget Sound sport fisheries; ii) 1991-1992 tributary sport recoveries in the Columbia River; and iii) escapement recoveries for most southern U.S. stocks.

b) Collect and provide information on the age and sex composition of escapement. Age and sex specific escapement data are essential to evaluate brood production, stock productivity, and escapement goals. Age specific data also improve the quality of the calibration of the CTC chinook model.

c) Tag representative Exploitation Rate indicator stocks at sufficient levels. The CTC is especially concerned about the lack of adequate representation of spring and summer stocks and the lack of an indicator stock (with escapement data) for Harrison River stock.

d) Establish consistent and standardized recovery programs for CWT fish at hatcheries and on spawning grounds. Accurate estimates of escapement are essential for the Exploitation Rate Assessment. The CTC is concerned that: i) pilot studies have indicated that many tagged fish may not be successfully identified at hatcheries; and ii) CWT fish which do not return to the hatchery may not be accounted for on a consistent basis. In addition, standardized procedures should be instituted for enumeration of marked and unmarked releases and tag retention rates.

e) Provide estimates of sublegal encounter rates in troll fisheries and legal and sublegal encounter rates in chinook nonretention and net fisheries. The CTC has estimated that incidental fishing mortality is approximately 30-50% of the reported catch (CTC 1987). However, sampling programs to determine the magnitude and stock composition of the nonlanded catch mortality are virtually nonexistent.

f) Provide estimates of nonreported chinook catches by Canadian Native fisheries. The CTC is unable to fully evaluate impacts of these fisheries on chinook stocks and the rebuilding program until these data are provided.

2) Conduct research on factors affecting freshwater and marine survival of chinook stocks. Factors such as predation, El Nino events, habitat destruction, and enhancement practices can significantly affect chinook production and the rebuilding program.