CHAPTER 1. SALMON SPAWNER SURVEYS IN THE UPPER TRINITY RIVER BASIN (CONTINUED)
Spawner distribution in the main-stem Trinity River is presented based on the seven-zone system first used in 1987 (Stempel 1988). The results for Zones 5 through 7 were combined this year because too few flagged chinook were recovered in these individual zones to make reliable estimates. Distribution in the tributaries is presented by individual tributary.
We observed 8,673 adult chinook salmon this season, excluding flag recoveries. The numbers of chinook salmon spawners were greatest in upstream zones, decreasing from a high of 4,897 fish in Zone 1 to 257 fish in combined Zones 5-7 (Table 5). We recognize that carcass counts alone cannot be used to accurately describe distribution because recovery efficiency can vary from zone to zone, due to differences in stream morphology. Therefore, the percentage of flags recovered for each zone was used to determine the recovery efficiency of that zone (Table 5).. Even based on the total number of chinook salmon recovered divided by the different recovery efficiency rates for each zone, the percent of chinook salmon spawners decreased downstream in successive zones below Zone 1 (Table 5).
As noted last year (Zuspan 1991a), a potential source of error in this estimate is the assumption that flagged chinook salmon carcasses are recovered only in the zone that they were originally flagged. If flagged fish are recovered in downstream zones, it would tend to increase the efficiency estimate in the recovery zone while decreasing the estimate in the flagging zone.
To determine the extent that carcasses drifted from one zone to another, fish flagged in each zone were given a distinct hog ring color. Recoveries that were originally flagged in another zone were recorded as such. Of the 2,253 flags recovered this season, only 18 (0.8%) were not flagged in the same zone that they were recovered. This indicates that carcass drifting had a negligible effect on chinook salmon distribution estimates.
We recovered 127 chinook and 9 coho salmon in the eight tributaries surveyed. The chinook salmon total includes 115 unmarked condition-one fish which we flagged, and 12 skeletons (Appendix 3). We also recaptured and re-examined 50 flagged carcasses. Too few salmon were observed in any of the tributaries to generate escapement estimates based on standard Jolly-Seber or Schaefer (Ricker, 1975) carcass survey models. However a rough estimate can be obtained by using the same method employed to expand the main-stem recoveries. For example, 31 chinook, consisting of 27 flagged fish and 4 skeletons, were observed in Canyon Creek this season. Of the chinook flagged, 5 (18.5%) were subsequently recovered. Adjusting for the 18.5% recovery rate, a total of 168 chinook spawned in the survey area this season. Since the survey area represents 97.0% of the total spawning habitat in the tributary, we estimate 173 chinook spawned in Canyon Creek this season. Using this methodology for the other tributaries surveyed, our results indicate that only Canyon Creek and the North Fork Trinity River had much spawning activity (Table 6) that we estimated to have occurred in all eight tributaries to the upper main-stem Trinity River.
Main-stem Trinity River. We observed 1,282 coho salmon, most of which were seen in Zones 1 and 2 (Table 7). Expanded spawner estimates, based on the recovery efficiencies developed from chinook salmon flag recoveries, indicate the majority of coho salmon also spawned in these two zones (Table 7).
Marked Salmon Recovery
We recovered 198 Ad-clipped salmon in the survey, which included 97 spring-run and 98 fall-run chinook salmon, and 3 coho salmon (Appendices 1 & 2). The percentage of Ad-clipped salmon in the survey is best estimated by considering only fish in relatively good condition (condition one), as fin clips are difficult to discern on fish in advanced decay. For condition-one fish, 4.1% of the spring-run chinook salmon, 2.9% of the fall-run chinook salmon, and 0.2% of the coho salmon were Ad-clipped. For comparison, at Junction City Weir, 15.1%, 9.4%, and 9.1% of the spring-run chinook salmon, fall-run chinook salmon, and coho salmon were Ad-clipped, respectively (Table 8).
The difference in Ad-clip percentages between the survey and Junction City Weir results primarily from a failure to identify Ad-clips in the survey. This was made apparent by comparing weir tagging records with survey recoveries. Seventeen chinook which had been identified as Ad-clipped when tagged at the weirs were subsequently recovered as condition-one fish in the survey. Of the 17, only five (29.4%) were correctly re-identified in the survey as being Ad-clipped. For both condition-one and condition-two fish, combined, the recognition rate was 20.0% (5/25). While it may be tempting to adjust the Ad-clip rates in the spawner survey by the apparent recognition rate (29.4%), it would be inappropriate because of the small (17) sample size driving the expansion. A re-evaluation of the 1988-89 data indicates that all condition-one, Program-marked fish were correctly identified upon recapture, that year.
Coded-wire tags were removed and decoded from 169 of the 198 Ad-clipped salmon recovered in the survey. All coded-wire tagged fish we recovered originated from Trinity River Hatchery (Appendix 6).
Tributaries. Of the total 127 chinook salmon recovered, five were Ad-clipped. All five were fall chinook tagged and released from Trinity River Hatchery (Appendix 6).
Main-stem Trinity River. We observed Program marks (spaghetti tags or operculum punches) on 215 chinook and 75 coho salmon during the survey. Most of these fish were tagged at Junction City Weir, followed by Willow Creek Weir, and, last, the seining operation at the mouth of the Klamath River (Table 9).
Tributaries. Program tags were recovered from nine of the 127 chinook salmon observed in the tributaries. Of these, seven were from Willow Creek Weir, one from Junction City Weir, and one from the seining operation at the mouth of the Klamath River.
Estimating the ratio of hatchery to naturally produced salmon spawning in the survey area relies entirely on correctly determining the ratio of Ad-clipped to unclipped salmon in the survey. Since, as stated in the section above, we failed to identify the majority of Ad-clips during the survey, even on condition one fish, estimating the incidence of hatchery-produced salmon spawning in the survey area would be inappropriate for this year.
This is the second year of a multi-year Program of spawner surveys in the Trinity River basin below Lewiston Dam. The following recommendations should be considered for inclusion in next year's spawner survey.
1. Spawner survey activities should be continued with current objectives in FY 1990-91.
2. Prespawning mortalities of female chinook salmon should be closely monitored to determine if they are continuing occurrence. The CDFG's fish pathologists should attempt to determine the cause(s) of the mortalities.
3. Survey efforts should be intensified so as to recover a higher proportion of the Ad-clipped salmon. Additional recoveries are necessary to reliably determine the incidence of hatchery-produced chinook salmon spawning naturally. Survey crews should be instructed to recover all fish with marginal or non-standard Ad-clips. Determination of whether these fish are actually Ad-clipped should be made in the lab by passing the fish through a tag-detector to determine if a coded-wire tag is present.
Gibbs, E. D. 1956. A report on king salmon, Oncorhynchus tshawytscha, in the upper Trinity River, 1955. Calif. Dept. Fish and Game, Inland Fish. Admin. Rep. No. 56-10. 14 p.
La Faunce, D. A. 1965. King (chinook) salmon spawning escapement in the upper Trinity River, 1963. Calif. Dept. Fish and Game, Mar. Res. Admin. Rep. No. 65-3. 10 p.
La Faunce, D. A 1968. Final Report, 1967 Spawning survey of the Trinity River. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1972. (Untitled file report) Summary of the 1972 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1973. (Untitled file report) Summary of the 1973 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1974. (Untitled file report) Summary of the 1974 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1976. (Untitled file report) Summary of the 1976 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1978. (Untitled file report) Summary of the 1978 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1979. (Untitled file report) Summary of the 1979 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1980. (Untitled file report) Summary of the 1980 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1981. (Untitled file report) Summary of the 1981 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1982. (Untitled file report) Summary of the 1982 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1984. (Untitled file report) Summary of the 1984 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Miller, E. 1985. (Untitled file report) Summary of the 1985 spawner survey in the upper Trinity River basin. Available from Calif. Dept. Fish and Game - Region I, 601 Locust St., Redding, CA. 96001.
Moffett, J. W., and S. H. Smith. 1950. Biological investigations of the fishery resources of the Trinity River, Calif. USFWS Spec. Sci. Rep., Fish. Bull. No. 12. 71 p.
Ricker, W. E. 1975. Computation and interpretation of biological statistics of fish populations. Canada Dep. of Environ., Fish. Res. Board Can. # 191 382 p.
Rogers, D. W. 1970. A king salmon spawning escapement and spawning habitat survey in the upper Trinity River and its tributaries, 1968. Calif. Dept. Fish and Game, Anad. Fish. Admin. Rep. No. 70-16. 13 p.
Rogers, D. W. 1973. King salmon, Oncorhynchus tshawytscha, and silver salmon, Oncorhynchus kisutch, spawning escapement and spawning habitat in the upper Trinity River, 1970. Calif. Dept. Fish and Game, Anad. Fish. Admin. Rep. No. 73-10. 14 p.
Rogers, D. W. 1982. A spawning escapement survey of anadromous salmonids in the upper Trinity River, 1971. Calif. Dept. Fish and Game, Anad. Fish. Admin. Rep. No. 82-2. 11 p.
Smith, G. E. 1975. Anadromous salmonid spawning escapements in the upper Trinity River, 1969. Calif. Dept. Fish and Game, Anad. Fish. Admin. Rep. No. 75-7. 17 p.
Stempel, M. 1988. Chinook salmon spawning survey in the upper Trinity River during the fall of 1987. USFWS file report. Available from USFWS F.A.O., P.O. Box 1450, Weaverville, Ca 96093.
Weber, G. 1965. North coast king salmon spawning stock survey 1956-57 season. Calif. Dept. Fish and Game, Mar. Res. Admin. Rep. No. 65-1. 34 p.
Zuspan, M. 1991a. Salmon spawner surveys in the upper Trinity River Basin. Chapter I. Job I. p. 1-23. In: Carpenter, R. and K. Urquhart (eds.), Annual Report of the Trinity River Basin Salmon and Steelhead Monitoring Project, 1988-1989 Season. August 1991. 51 p. Available from Calif. Dept. Fish and Game, Inland Fish. Div.-Room 1251, 1416 9th St., Sacramento, Ca. 95814.
