*U.S. Dept Commerce/NOAA/NMFS/NWFSC/Publications*

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**NOAA F/NWC-187 - Status and Future of Spring Chinook Salmon in the Columbia River Basin—Conservation and Enhancement**
**STATUS OF CHINOOK SALMON STOCKSIN THE MID-COLUMBIA**
James W. Mullan

U.S. Fish and Wildlife ServiceLeavenworth, Washington 98826

It is widely believed that chinook salmon stocks in the mid-Columbia River we severely depressed.Here I develop a paradigm that demonstrates that populations are stable and that the streams in this regionnow rear chinook salmon at carrying capacity.

The Wenatchee, Entiat, and Methow Rivers support wild spring chinook salmon. LeavenworthNational Fish Hatchery (NFH) releases about 2.4 million spring chinook salmon yearlings annually toIcicle Creek, a tributary of the Wenatchee River. Entiat and Winthrop NFHs release about 1.0 millionyearlings to the Entiat and Methow River.

I assessed escapements to the Wenatchee, Entiat, and Methow Rivers as the differences betweenadult counts at appropriate dams. Wild adult escapement equaled interdam count less fish that returned tohatcheries or were harvested. I divided spawner/redd ratios of 2.4 (Kohn 1988 for the Methow River;Hollowed 1983 for the Yakima River) and 3.1 (Meekin 1967 for the Mathew River) into interdam countsof wild spring and summer/fall chinook salmon, respectively, to account for prespawning mortality. I usedan egg deposition of 4,600 per spring chinook salmon female (12-year average at Leavenworth NFH) and5,240 per summer/fall female (Mathews and Meekin 1971). Annual losses of stream salmonids weuniversally high (Alexander 1979), and I assumed 50% overwinter mortality for age-0 chinook salmon.

About half of the area used by anadromous fish in the three drainages has been physically measured.Samples were expanded to account for total wetted area (1,476 ha) at low flow in September. Fishdensities were assessed by snorkelers (Schell and Griffith 1984), sodium cyanide census (Wiley 1984), orboth, in 2.1% (31.3 ha) of the was, 1983-87. Snorkel counts of juveniles were calibrated against cyanidecensuses (Hillman et al., in press). Sampled fish habitat was ranked with Binns' (1982) Habitat QualityIndex (HQI, which rates late summer flow, annual flow variation, water temperature, food, cover, watervelocity, nitrate nitrogen, and stream width with an index of nonsalmonids substituted for bank erosion.

A mean of 8,431 naturally-produced spring chinook salmon returned to the Wenatchee (4,465),Entiat (1,247), and Methow (2,719) Rivers 1967-87. I assumed mean per-project adult loss of 5%(Northwest Power Planning Council 1986), then calculated mean adult abundance at the Columbia Rivermouth as 12,600. In-river catch averaged 20% (3-39%, Oregon Department of Fish and Wildlife andWashington Department of Fisheries 1988), which should increase adults to 15,750. A 10% correctionfor ocean harvest (Northwest Power Planning Council 1986) yields a total run of 17,400. I foundsuggestions of an inverse relationship between spawning escapement and total run 4 years later (Fig. 1).Hatchery spring chinook salmon abundance fluctuated in much the same manner, which suggests theubiquitous importance of ocean survival (Fig. 2).

I extrapolated rearing densities for the total drainage rearing uses by HQI ranking, and produced arange in late-summer or early-fall population estimates (Table 1). For example, I multiplied a homogenousstream reach area, with HQI of 20, by the poor density value (2.5 age-0 chinook/100 m2) and the fairvalue (3.8 age-0 chinook/100 m2). Egg-to-fall fingerling survival of naturally produced spring chinooksalmon thus ranged from 2.7 to 13.3%; and smolt-to-adult survival from 1.6 to 8.1%. Mean hatcherysmolt-to-adult survival ranged from 0.16 to 0.55%, 1976-88. Naturally produced smolts were about 10-80 times as viable as hatchery smolts (Table 2).

Spring chinook salmon typically ascend to headwaters during high water in spring, and their offspringrear there for a yew or more before smolting (this produces a stream-annulus on scales). Ocean-annuluschinook salmon usually return in summer and fall and spawn downstream from spring chinook salmon, andtheir offspring leave these milder climes at age-0. Stream fish are less common at sea and apparentlydistribute widely there. The more common ocean-annulus chinook salmon occur more frequently incoastal waters (Mullan 1987).

Mean escapement to the Wenatchee (12,012), Enlist (100), and Methow (3,385) Rivers for naturally-produced chinook salmon with ocean-type first annuli from 1967 to 1987 was 15,497. Corrected for 5%interdam. loss, incidental in-river catches of 9%, and mean harvest of 75% in 1967-84 (Northwest PowerPlanning Council 1986) and more recent harvests of about 40%, total run size was about 88,600 naturally-produced ocean-type chinook salmon (Wenatchee—68,600; Entiat—570; Methow—19,350). Although meanharvest data we not specifically available for all years, it is apparent that the trend in escapements to theWenatchee River in the past 27 years was relatively stable. This suggests that the habitat was fully seededeven at low escapements (Fig. 3).

I estimated juvenile migrants with three different statistics (Table 3). I adopted an estimated output ofabout 20 smolts per 100 m2 because most summer/fall chinook habitat ranks poor to fair in summer butgood to excellent in spring, when shoreline vegetation floods. Estimated egg-to-migrant survival for wildsummer/fall chinook salmon ranged from 4.8 to 15.2%, excluding a 45% aberrant value for the Entiat River(Table 3). The Entiat River is at best marginally suitable for summer/fall chinook salmon (Mullan 1987).Most probable migrant-to-adult survival was 2.2 to 14.2% (Table 3).

Temporal variation in abundance causes problems in population estimates based on standing crop (Hall and Knight 1981). The range in age-0 chinook salmon densities (0.6-21.2/100 m2) during September 1985-88 in an experimental section of Icicle Creek was 100% of mean abundance (10.5/100 in2) (Mullan 1989,unpublished). Hillman and Chapman (1989) observed only a small difference between age-0 chinooksalmon densities in the Wenatchee River in September 1986 (1.4/100 in2) and 1987 (1.1/100 in2). The meandensity observed by snorkeling was higher in late August 1985 (2.4/100 in2). This range in standing cropencompasses the variation (Table 1) used in estimating chinook salmon abundance.

Survival rates in Table 3 lie within hounds of those reported by others. Major and Mighell (1969)estimated that 5.4-16.4% of potential spring chinook egg deposition survived to smolt in the Yakima River.Fast et al. (1988) reported 4.2-6.5% egg-to-smolt survival in the Yakima system.

Rum of adult stream chinook salmon in the undammed Fraser River average only 19,000 to 31,500 (U.S.-Canada 1984), compared to 17,400 for the mid-Columbia. The Wenatchee, Entiat, and Methow Rivers contribute only 2% of the average flow of the mid-ColumbiaRiver, and there is no evidence that these streams ever produced mom fish than they now do (Mullan 1987).

Low returns of hatchery Chinook salmon (Mullan 1987) seem to lie outside the purview of fish health and genetics. This is not to say that diseases and genetics are unimportant, but I see hints that the behavior of Chinook salmon in hatcheries is conditioned—like that of Pavlov's famous dogs—differently from that of wild fish. For example, large age-0 and yearling spring chinook salmon released toIcicle Creek do not orient to cover, remain at the water surface, and drift downstream in the channelregardless of season. They haw no apparent social structure and frenzy when hit by light at night (Hillmanand Mullan 1989). Recently-hatched fry released to Icicle Creek, by contrast, quickly removethemselves from strong currents and mimic the behavior of naturally-produced Chinook as described byHillman at al. (1989a, b). Exceptions to low hatchery returns almost invariably involve chinook salmonleast exposed to hatchery life (Heard 1987).

**Acknowledgements**

I thank K. Williams, G. Rhodos, T. Hillman, and J. McIntyre for Crucialcontributions.

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**References**

Alexander, G. R. 1979. Predators of fish in Coldwater streams. *In* H. Clapper (editor), Predator-prey systems in fisheries management, p. 53-170. Sport Fishing Institute, Washington, D.C.

Binns, N. A. 1982. Habitat quality index procedures manual. Wyoming Game and Fish Department,Cheyenne, WY, 209 p.

Fast, D. E., J. D. Hubble, and B. D. Watson. 1988. Yakima River spring Chinook enhancement study. Annual report, Yakima Indian Nation to Bonneville Power Administration, Contract DE-A179-83BP39461, 101 p. (Available from Bonneville Power Administration, U.S. Department ofEnergy, P.O. Box 3621, Portland, OR 97208.)

Hall, J. D., and N. J. Knight. 1981. Natural variation in abundance of salmonid populations and its implications for design of impact studies. Report to Corvallis Environmental Research Lab, Contract EPA-600/3-81-021, 85 p. (Available from Oregon State University, Department ofFisheries and Wildlife, Corvallis, OR 97331.)

Heard, W. R. (editor). 1987. Report of the 1987 Alaska Chinook salmon workshop. NWAFCProcessed Rep. 88-06, 244 p. Alaska Fish. Cent., Ned. Mar. Fish. Serv., NOAA, P.O. Box210155, Auke Bay, AK 99821.

Hillman, T. W., and D. W. Chapman. 1989. Abundance, growth, and movement of juvenile Chinooksalmon and steelhead. *In* Don Chapman Consultants (editors), Slimmer and winter ecology ofjuvenile Chinook salmon and steelhead trout in the Wenatchee River, Washington, p. 1-41.Report to Chelan County Public Utility District, Wenatchee, Washington. (Available from DonChapman Consultants, P.O. Box 1362, McCall, ID 83638.)

Hillman, T. W., D. W. Chapman, and J. S. Griffith. 1989a. Seasonal habitat use and behavioralinteraction of juvenile chinook salmon and steelhead. 1: Daytime habitat selection. In DonChapman Consultants (editors), Summer and winter ecology of juvenile chinook salmon andsteelhead trout in the Wenatchee River, Washington, p. 42-82. Report to Chelan County PublicUtility District, Wenatchee, Washington. (Available from Don Chapman Consultants, P.O. Box1362, McCall, ID 83638.)

Hillman, T. W., D. W. Chapman, and J. S. Griffith. 1989b. Seasonal habitat use and behavioralinteraction of juvenile chinook salmon and steelhead. II: Nighttime habitat selection. *In* Don Chapman Consultants (editors), Summer and winter ecology of juvenile chinook salmon andsteelhead trout in the Wenatchee River, Washington, p. 83-108. Report to Chelan County PublicUtility District, Wenatchee, Washington. (Available from Don Chapman Consultants, P.O. Box1362, McCall, ID 83638.)

Hillman, T. W., and J. W. Mullan. 1989. Effect of hatchery releases on the abundance and behavior of wild juvenile salmonids. *In* Don Chapman Consultants (editors), Summer and winter ecology of juvenilechinook salmon and steelhead trout in the Wenatchee River, Washington, p. 265-285. Report toChelan County Public Utility District, Wenatchee, Washington. (Available from Don ChapmanConsultants, P.O. Box 1362, McCall, ID 83638.)

Hillman, T. W., J. W. Mullan, and J. S. Griffith. In press. Accuracy of underwater counts of juvenilechinook and coho salmon and steelhead. N. Am. J. Fish. Manage.

Hollowed, J. 1983. Age, sex and size of Yakima Basin spring chinook (*Oncorhynchus tshawytscha*), from catch and escapements 1980-1983. Information Report 83-9, Yakima Indian Nation. (Available from Yakima Indian Nation, P.O. Box 151, Toppenish, WA 98948.)

Kohn, M. 1988. Spring and summer chinook [salmon] spawning ground surveys, Methow and OkanoganRiver Basins, 1988. Report of Yakima Indian Nation to Chelan Co. PUB, Wenatchee, Washington.41 p. (Available from Yakima Indian Nation, P.O. Box 151, Toppenish, WA 98948.)

Major, R. L., and J. L. Mighell. 1969. Egg-to-migrant survival of spring chinook salmon(*Oncorhynchus tshawytscha* in the Yakima River, Washington. Fish. Bull., U.S. 67(2):347-359.

Mathews, S. B., and T. I. Meekin. 1971. Fecundity of fall chinook salmon from the upper Columbia River. Washington Department of Fisheries, Tech. Rep. 6:29-37.

Meekin, T. K. 1967. Report on the 1966 Wells Dam chinook tagging study. Report to Douglas County PUB, Contract 001-01-022-4201. Washington Department of Fisheries, Olympia, Washington. 41 p. (Available from Douglas County PUD, 1151 Valley Mall Parkway, East Wenatchee, WA 98801.)

Mullan, J. W. 1987. Status and propagation of chinook salmon in the mid-Columbia River through 1985.U.S. Fish and Wildlife Service Biol. Rep. 89(3):1-111.

Mullan, J. W. 1989. Growth, survival, and production of salmon and steelhead in a controlled section of Icicle Creek, Washington. Unpubl. manuscr., 55 p. U.S. Fish and Wildlife Service, Leavenworth, Washington.

Northwest Power Planning Council. 1986. Compilation of information on salmon and steelhead lossesin the Columbia River Basin, 25 p. (Available from Northwest Power Plannin Council, 851 SWSixth Ave., Suite 1100, Portland, OR 97204.)

Oregon Department of Fish and Wildlife and Washington Department of Fisheries. 1988. Statusreport: Columbia River fish runs and fisheries, 1960-87. Portland, Oregon and Olympia,Washington. 83 p. (Available from ODFW, P.O. Box 59, Portland, OR 97207.)

Schell, D. D., and J. S. Griffith. 1984. Use of underwater observations to estimate cutthroat trout abundance in the Yellowstone River. N. Am. J. Fish. Manage. 4:479-487.

U.S.-Canada Technical Committee on Chinook Salmon. 1984. Report to advisors to the U.S.-Canada negotiations on the limitations of salmon interceptions, 46 p. (Available from U.S. Fishand Wildlife Service, FAO, Leavenworth, WA 98826.)

Wiley, R. W. 1984. A review of sodium cyanide for use in sampling stream fishes. N. Am. J.Fish. Manage. 4:249-256.

**QUESTIONS AND ANSWERS**
- Q:
- Did you allow for 20% of broodstock trapped at Priest Rapids?

- A:
- Yes, but I was not talking about either Okanogan or Rocky Reach Dam.

- Q:
- Are you suggesting that we increase hatchery outplants?

- A:
- No; we can spend the next 30 years on IHN virus or genetics and it wouldn't change a thing. The problem is in chinook salmon behavior. Wild fish and hatchery fish behave very differently. Hatchery fish cannot be raised to act like wild fish. In the Great Lakes them is a 17% return, which is now equal to the historical capacity, and therefore the system is full.

- Q:
- Is no one going to challenge that?

- Q:
- Are the summer and fall chinook salmon using the Wenatchee system to the historical extent?

- A:
- These runs were wiped out at the time Grand Coulee Dam was built. In the 1930s, Washington Department of Fisheries maintained that them had never been a run of summer chinook in the Wenatchee River. They wanted the Bureau of Reclamation to provide water at Dryden Dam, and said that the Grand Coulee project had introduced exotic races. The Bureau of Reclamation went through all the records at the time, and that is what was used. Them is not much historical evidence.

- Summer chinook salmon me confined to the Wenatchee River, and in some years then are 2,000redds in 50 miles of stream; the capacity is at maximum right now. Rocky Reach was severelydepleted to about 2,000 fish by overfishing. I cannot find records of more than the present numbersof fish, although I may have missed something.

- Q:
- Than what is the baseline to compare with your present numbers?

- A:
- If one considers like habitat, these streams me doing as well as any.

- Q:
- How did you arrive at your figure of 50% for fingerling-to-smolt survival?

- A:
- This was based on the world literature.

- Q:
- There me indications that some streams in Idaho me not at fun capacity, so why do you believe that these three upper Columbia streams are at full capacity?

- A:
- This is for spring chinook salmon, where smolts me at capacity, not adults produced. This is not the case for coho salmon, which I have not mentioned—coho salmon were important in the Methow River, but they are now extinct there.

- Q:
- What about the fact of dams now, and the related survival problems—wouldn't we see more fish without these problems?

- A:
- Yes, we would; no one would deny that they don't kill fish. There is, however, as much productionof smolts as before. Therefore, there is also no room for outplanting.

Figure 1. Spawning escapement, natural spring chinook salmon to Wenatchee River.

Figure 2. Leavenworth hatchery releases of spring chinook salmon.

Figure 3. Interdam escapements of summer/fall chinook salmon to Wenatchee River.

Table 1. Average (weighted) densities (number of fish/100 m2) of age-0 chinook salmon, age-0 steelhead trout, steelhead trout, steelhead trout parr, and total salmonids (exclusive of mountain whitefish) according to habitat quality indexing (HQI) of poor, fair, average, good, and excellent for mid-Columbia River tributaries.

* Includes rainbow/steelhead >200 mm, cutthroat trout, eastern brook trout, bull trout, and hatchery coho salmon.

Table 2. Life table for spring chinook salmon in mid-Columbia River tributaries.

Table 3. Life table for summer/fall chinook salmon in mid-Columbia River tributaries with migration estimates from three sources.

a Observed from experimental section of Icicle Creek, 1986-89.b Estimated from Table 1, density according to HQI rating of excellent.c Wenatchee R. June densities minus July densities (Hillman and Chapman 1989).

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