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

This report of the Chinook Technical Committee (CTC) updates our previous comprehensive stock assessment report (TCCHINOOK (96)-1, data through 1994). We provide a summary of fishery catches and management actions in 1995 and 1996, and an assessment of escapement and exploitation rates through 1996. Key points in the report are summarized below.

The Chinook Annex of the PST implemented in 1985 established ceilings for the catch of all gear types in Southeast Alaska (SEAK; 263,000) and North/Central British Columbia (NCBC; 263,000), the West Coast Vancouver Island (WCVI; 360,000) troll fishery, and the Strait of Georgia (GS; 275,000) sport and troll fishery. These provisions for catches (referred to as base ceilings) subsequently expired and, in 1995 and 1996, the parties were unable to reach agreement on suitable replacements. Catches in 1995 and 1996 (not including hatchery add-on and terminal exclusions) were lower than the base ceilings, and retention of chinook was not permitted in the WCVI troll fishery in 1996.

The status of 42 naturally spawning escapement indicator stocks was assessed using prior CTC procedures and additional information presented by the relevant management agencies. This assessment indicates that:

1. In 1995, the SEAK/TBR stocks completed their defined 15-year rebuilding period. Substantial progress has been made towards rebuilding these stocks. At the end of their rebuilding period, there is no evidence of escapement declines relative to the base period. Nine of the 10 stocks were Stable at Goal or had increased since the base period, and the other stock (Chickamin) had a recent escapement that was indistinguishable from base (Table 2-8). Five of the stocks (50%) were classified as Rebuilding or Stable at Goal, while 2 (20%) were Not Rebuilding in relation to the escapement goals the CTC used for the assessment (Table 2-9). The remaining 3 stocks (30%) were Indeterminate.
2. The other escapement indicator stocks, located in Canada south of the SEAK/TBR rivers and in the Pacific Northwest have a target date of 1998 for completion of their 15-year rebuilding program. These stocks included 24 stocks with escapement goals and 8 without goals. Thirty-one of these stocks were evaluated for changes in escapement relative to their respective base period; one stock (WCVI) was excluded from this analysis due to significant changes in escapement methodology. Of the 31 stocks evaluated through 1996, most (77%) have been Stable at Goal, have increased, or have remained indistinguishable in escapement magnitude relative to the base period (Tables 2-4, 2-8). However, seven (22%) of these stocks have shown escapement declines after 13 years of the rebuilding program. Of the 24 of these stocks with escapement goals, 11 (46%) were Stable at Goal, Above Goal, or Rebuilding, while 12 (50%) were Not Rebuilding or Declined Below Goal (Table 2-9). One stock was Indeterminate.
3. While assessment of progress toward attaining interim chinook escapement goals is the specific task of this chapter, some members of the CTC do not believe that application of the current algorithm results in an accurate assessment of rebuilding. The specific concerns of these members include: inconsistency in survey methodologies results in data sets of very different quality being treated equally; the numerous interim escapement goals may have no relevance to maximum sustained yield escapement goals; apparent erroneous conclusions may be reached if the algorithm is strictly applied; the current summarization of rebuilding progress does not distinguish between very small and very large stocks; and, the precision of the various escapement estimates has not been incorporated in the analysis.

The 1996 season required that the CTC make several changes to the exploitation analysis methods. Prior to 1996, incidental mortalities during CNR fisheries were calculated using information from the chinook retention portion of the fishery. For the 1996 analysis, a new method was developed to estimate CNR mortality based on encounter rates during a base period (Section 3.2.1.2). In addition, the age 2-3 survival index for 1996 was converted to express all recoveries as spawner equivalents (AEQ). This conversion was implemented to compensate for the under-estimation of cohort survival resulting from the closure of some Canadian fisheries (a substantial portion of the age-2 and age-3 chinook recoveries are usually catch recoveries). The cohort analysis was further modified in 1996 to incorporate the incidental mortality rates for troll and sport fisheries recommended by the CTC (TCCHINOOK (97)-1)(Section 3.2.1.1)

Examination of coded-wire tag data for 18 of the 39 exploitation rate indicator stocks (Table 3-3) indicated that:

1. In 1996, fishery indices for both reported catch and total mortality were below base levels in all PSC ceiling fisheries (Table 3-6, Figures 3-1 through 3-4). Total mortality fishery indices for 1996 were reduced from base period levels by 52% in SEAK troll, 98% in NCBC troll, 95% in WCVI troll, and 17% in the Strait of Georgia troll and sport fisheries. Similarly, reported catch fishery indices for 1996 were reduced from base period levels by 61% in SEAK troll, 100% in NCBC troll, 99% in WCVI troll, and 32% in the Strait of Georgia troll and sport fisheries. The 1995 and 1996 total mortality and reported catch fishery indices for NCBC and WCVI troll were below the projected indices from the 1984 chinook model. The SEAK troll and Strait of Georgia total mortality indices were above the 1984 projected index in both 1995 and 1996. The total mortality and reported catch fishery indices for U.S. South ocean troll and sport were reduced 67 and 65% from the base period levels in the Columbia River stock group and increased 47 and 53% from base in the Puget Sound stock group.
2. In 1995 and 1996 nonceiling fisheries, harvest rates on wild stocks subject to the passthrough provision were below base period levels and therefore met the CTC’s suggested interpretation of passthrough obligations (CTC 1991) (Figures 3-7 through 3-14). In 1995, nonceiling fishery indices were at or near zero for Upper Georgia Straight, just below 1.0 for Skagit, Snohomish, and Stillaquamish Summer/Fall, and ranged from 0.3-0.8 for Columbia River Summer, Grays Harbor, and Quillayute Summer. In 1996, nonceiling fishery indices were again near zero in the Straight of Georgia and ranged from 0.3-0.8 for the other fisheries.
3. Brood year 1992 exploitation rates declined from brood year 1991 rates for both total mortality and reported catch for all five of the ocean type (age 0 migrant) stock groups (Figures 3-15 through 3-21). In all stock groups except SEAK/TBR-I, brood year 1992 exploitation rates based on total fishing mortalities indicate a 10-70% reduction in ocean exploitation rates relative to the base period. For SEAK/TBR, the 1991 brood year total exploitation rate is 30% above the base period. Similarly, in all stock groups except SEAK/TBR-I, exploitation rates based on reported catch indicated a 30-100% reduction in ocean exploitation rates relative to the base period. For SEAK/TBR, the 1991 brood year total exploitation rate based on reported catch is 10% above the base period. The 1992 brood total mortality exploitation rate index for LGS is higher than the 1984 projection from the CTC chinook model. The 1992 brood total mortality exploitation rate indices for the WACO and WCVI stock groups are lower than projections from the CTC chinook model.
4. The age 2-3 survival indices are generally either declining or stable at levels indicating poor survival (Appendix F). An exception is the Columbia Upriver Bright index, which has been increasing from 1991 until 1993. However, the brood year 1994 age-2 index for this stock was not computed because there were no CWT recoveries reported in 1996. While it is true that major Canadian ocean-troll fisheries were closed to chinook retention in 1996, the CTC is concerned that a complete lack of CWT recoveries, including hatchery rack recoveries, may signal poor survival of the 1992 brood. Other stocks with no age-2 recoveries in 1996 include Robertson Creek, Hoko Fall Fingerling, White River Spring Yearling, Cowlitz Fall, and Stayton Pond.

The 15-year rebuilding period for chinook salmon identified for the PST has or will soon conclude. Despite substantial reductions in fishery exploitation rates, 50% of the escapement indicator stock located in Canada south of the SEAK/TBR rivers and in the Pacific Northwest are currently classified as Not Rebuilding or Declined Below Goal. To evaluate and refine management options for these stocks, the CTC should:

1. improve the methods used to assess the status of the escapement indicator stocks;
2. identify the factors contributing to the status of stocks classified as Not Rebuilding or Declined Below Goal;
3. estimate the stock-recruit productivity relationship and escapement goals for the escapement indicator stocks; and
4. convene a workshop to foster understanding of recent developments in stock-recruit analysis and generate collaboration and consensus in CTC analyses.

Even with these improvements, the quality of the CTC assessments can be no better than the basic resource data collected by the management agencies. As previously noted by the CTC (1992):

Due to the limited scope of this report, stock catch distributions are not discussed in the text, but are presented in Appendix B. Additional information on escapements, terminal runs, and the methods and data used to calculate the exploitation rate indices can be found in Appendices A, C, D, E, F, and G.