FOREWORD

This is the first annual report to the United States Bureau of Reclamation (USBR) of activities conducted under the terms of Cooperative Agreement Number 8-FC-20-07100, and covers the period July 1, 1988 through June 30, 1989. The field work was conducted by personnel of the California Department of Fish and Game's (CDFG) Klamath-Trinity Program, specifically its Natural Stocks Assessment Project and Trinity River Fisheries Investigations Project.

by

Mark Zuspan

ABSTRACT

Staff of the California Department of Fish and Game's Trinity River Fisheries Investigations Project conducted a mark-and-recovery, salmon spawner survey of the upper main stem Trinity River from September 20 through December 19, 1988. The survey began at the upstream limit of anadromous migration at Lewiston Dam and ended at the confluence of the North Fork Trinity River, 64.2 km downstream. We examined 5,662 chinook salmon (Oncorhynchus tshawytscha) and 609 coho salmon (O. kisutch) during the survey. Chinook salmon spawner concentration was highest in the upper 3.1 km of the river where 40.2% spawned, followed by the next 25.7 km with 47.8%, and the remaining 35.4 km with 12.1%.

Females comprised 63.4% of the subsample of 1,753 adult chinook sexed during the survey. A subsample of 468 coho (adults and grilse) contained 42.3% females. The percentage of female chinook salmon which died prior to spawning ranged from a high of 75% early in the survey to 23% during the last few weeks. The overall female chinook salmon prespawning mortality rate during the survey was 44.9%.

We recovered both spring-run and fall-run chinook salmon in the survey. Spring-run fish dominated recoveries until mid-October when fall-run fish became prevalent. Fork lengths ranged from 46 to 85 cm for spring-run, and 36 to 107 cm for fall-run chinook. Adult chinook salmon comprised 99.1% of the spring-run and 90.8% of the fall-run, with grilse comprising the remainder.

We recovered 121 adipose-fin-clipped chinook salmon in the spawner survey. Of those carcasses recovered in the best condition (firm bodied with at least one clear eye), 7.7% of the spring-run and 3.0% of the fall-run chinook salmon had adipose fin-clips.

JOB OBJECTIVES

1. To determine, through a system of spawning ground surveys, the distribution of naturally spawning chinook and coho salmon in the mainstream Trinity River and its tributaries upstream of an including the North Fork Trinity River.

2. To determine the incidence of pre-spawning mortality among naturally spawning salmon in this area.

3. To determine the size and sex composition and incidence of marked/tagged individuals among the naturally spawning populations in this area.

INTRODUCTION

This is the latest in a series of salmon spawner surveys of the main stem Trinity River, begun in 1942, which were conducted either by the California Department of Fish and Game (CDFG) or the United States Fish and Wildlife Service (USFWS). The first three surveys (Moffett and Smith 1950, Gibbs 1956, and Weber 1965) were fishery evaluations prior to the construction of Lewiston Dam. Later surveys (LaFaunce 1965, Rogers 1970, 1973, 1981; Smith 1975, and Stempel 1988) were post dam construction studies designed to evaluate the effects of the dam on the salmon resource.

In 1984, Congress enacted the Trinity River Basin Fish and Wildlife Management Program (U.S. Public Law 98-541). This law appropriated approximately $57 million to be spent for fishery and wildlife restoration and monitoring within the Trinity River basin.

This survey, and those scheduled for following years by CDFG's Trinity River Fisheries Investigations Project, will help to evaluate the effectiveness of increasing spawning habitat in the basin through habitat improvement efforts that are part of the restoration program.

METHODS

Our study area included the main stem Trinity River from its upstream limit to anadromous fish migration at Lewiston Dam to the confluence of North Fork Trinity River, approximately 64 km downstream (Figure 1). We did not undertake any surveys of tributaries to the Trinity River this year, due to vacancies in permanent staff positions and difficulties hiring temporary help. Previous studies have divided the river into both a four- and seven-zone system. The seven-zone system was used in 1987 by the USFWS (Stempel 1988). Prior to this, with the exception of Moffett and Smith 1950, all surveys were based on a system utilizing four zones in the river reach below Lewiston Dam (Gibbs 1956; Weber 1965; LaFaunce 1965; Rogers 1970, 1973, 1981; and Smith 1975). To allow for comparisons to all years, data were collected based on both zone systems (Figure 1).

FIGURE 1 Map of upper Trinity River showing spawner survey zones used in September through December 1988. [7 zone system - Stempel 1988; 4 zone system - Gibbs 1956 and later authors]

CDFG staff conducted the survey using two 12-ft Avon inflatable rafts equipped with rowing frames. Raft crews consisted of a rower and one or two personnel to recover carcasses. Carcasses were recovered on foot along the shore and with long handled gigs in deep water.

We attempted to survey the entire study section once a week through the salmon spawning season. However, high flows resulting in dangerous rafting conditions and staffing problems precluded sampling during some periods (Table 1).

		Survey zones
Survey week	Start date	1	2	3	4	5	6	7
1	19-Sep	X a/	X	X	X	X	X	X
2	26-Sep	X	X	X	X	X	X	X
3	03-Oct	X	X	X	X	X	X	-
4	10-Oct	X	X	X	X	X	X	-
5	17-Oct	X	X	X	X	-	-	-
6	24-Oct	X	X	X	X	X	X	X
7	31-Oct	X	X	X	X	-	X	X
8	07-Nov	X	X	X	X	X	X	X
9	14-Nov	X	X	X	X	X	X	X
10	21-Nov	X	X	-	-	X	X	X
11	28-Nov	X	X	X	X	X	X	X
12	05-Dec	X	X	X	X	X	X	-
a/ Completed effort noted with an "X"; incomplete effort noted with a dash "-".

TABLE 1. Effort summary for the 1988 Trinity River spawner survey.

We determined spawning condition in female salmon by direct observation of the ovaries. Fish were classified as either spawned or unspawned based on egg retention. Females which retained over 50% of their eggs were classified as unspawned. Male spawning condition was not assessed, as its determination was considered to be too subjective.

All carcasses observed were identified by species and examined for an adipose fin-clip (Ad-clip) indicating the presence of a coded-wire tag (CWT) in their snout. Fish were further examined for the presence of an external tag (spaghetti tag) and/or an opercle punch, applied as part of an ongoing study by other elements of the CDFG's Klamath-Trinity Program. Spaghetti tags and opercle punches (Program marks) are placed on returning adult fish at various tagging locations downstream of the survey site.

Chinook Salmon

We classified all chinook salmon carcasses as either condition one or two, based on the extent of body deterioration. Condition-one fish were the freshest, having at least one clear eye and a relatively firm body. Condition-one fish were assumed to have died within one week prior to recovery. Condition-two fish were in various advanced stages of decomposition and assumed to have died more than one week prior to recovery. We did not count partially intact fish skeletons, because they could have represented Program-marked or condition-two fish which had already been counted and chopped in half during a previous weeks survey.

All chinook salmon recovered were further classified into four categories:(i) Ad-clipped fish; (ii) Program-marked fish; (iii) condition-one, unmarked fish; (iv) condition-two, unmarked fish. The category assigned determined what data we collected from each fish.

We sexed and measured Ad-clipped fish to the nearest cm fork length (FL), and determined their condition and spawning success. Heads of Ad-clipped fish were removed and retained for later CWT recovery and decoding.

Program-marked fish were sexed, measured (cm, FL), and assessed for spawning condition. We removed any spaghetti tags and then cut the fish in half with a machete to prevent counting in future weeks. Spaghetti tags have a unique number which allowed determination of date and location of tagging.

Condition-one fish which were neither Ad-clipped or Program-marked were flagged and returned to moving water, for subsequent recovery, and a subsample of them were measured for FL (cm). Flags consisted of plastic survey tape wrapped tightly around a hog ring and affixed to the left mandible of the carcass. The survey tape was wrapped so tightly around the hog ring, that it amounted to no more than a colored coating, with less than 2.5 cm of tape extending from the hog ring at any time. Flag colors were changed weekly so that, on recovery, the week of flagging could be determined. Chinook < 56 cm were classified as grilse during the carcass surveys. Actual grilse to adult ratios for the whole population of male chinook in this years run were determined from post-season evaluations of CWT data.

Condition-two fish which were neither Ad-clipped or Program-marked were checked for the presence of a flag and, if possible, the spawning condition was assessed. If a flag was present, the color was recorded and all fish were then cut in half to prevent later recovery and re-counting of the same fish.

Coho Salmon

All coho salmon we collected were checked for the presence of Ad-clips or Program-marks. When possible, the sex and spawning condition were determined and then all coho salmon were cut in half to prevent future re-counting. Coho carcasses were not used in the flagging experiment, since they would have required a separate series of flag colors to segregate them from flagged chinook salmon.

RESULTS AND DISCUSSION

Numbers Observed

Chinook Salmon

We observed 5,662 chinook during the spawner survey. This total included 121 Ad-clips (6 also Program-marked), 226 Program-marks (6 also Ad-clipped), 1,068 unmarked, condition-one fish which were flagged, 172 flag recoveries, and 4,082 unmarked, condition-two fish (Appendix 1). We did not see any whole skeletons.

Coho Salmon

We recovered 609 coho in the spawner survey, including 46 Program marks (Appendix 2), and did not see any whole skeletons.

Spring and Fall Chinook Salmon Spawning Run Timing

Both spring and fall race chinook salmon were observed in the survey. A date separating the two races was determined from CWT and Program-marked chinook salmon. Spring chinook salmon dominated our recoveries through the third week of the survey ending October 10, 1988. Fall chinook salmon became dominant by the fourth week of the survey, beginning October 11 (Figure 2). Some overlap of spring and fall chinook salmon occurred during that week. However, all chinook recovered from October 11, 1988, onward were considered fall race, while those recovered prior to that date were considered spring race, for the purposes of this report.

FIGURE 2. Spring and fall chinook salmon run timing, determined from weekly carcass recoveries of coded-wire tagged and Program-marked chinook in the 1988 Trinity River spawner survey.

Size Composition

Spring Chinook Salmon

We measured the size (cm, FL) of 532 spring chinook salmon during the survey, which included 432 flagged , 66 Ad-clipped, and 34 Program-marked fish. Adults (fish >50 cm FL [Bill Heubach, Assoc. Fishery Biologist, CDFG, personal communication]) comprised 99.1% (527/532) of the spring chinook observed in the spawner survey, while grilse (fish <50 cm FL) comprised the remaining 0.9% (5/532) (Table 2, and Figure 3). The percentage of spring chinook salmon grilse varied significantly (X =252, df=3, P=.0001) between the spawner survey and three fixed sampling locations in the Trinity River (Table 2). The reasons for the difference in grilse percentages at the different sites are unknown.

Fall Chinook Salmon

We measured the FLs of 774 fall chinook salmon, which included 636 flagged, 48 Ad-clipped, and 90 Program-marked fish. Based on a minimum FL of 57 cm for adults (Bill Heubach, Assoc. Fishery Biologist, Calif. Dept. Fish Game, pers. comm.), 90.8% of the fall chinook were adults and 9.2% were grilse (Figure 4, and Table 3). For comparison, the percentage of fall chinook salmon grilse at the different sampling sites ranged from 9.2% to 21.5% (Table 3). As with spring chinook salmon grilse, the reasons for the difference in fall grilse rates between the sample sites are unknown, although in both cases, the lowest rates were observed in the spawner survey.

	Willow Creek Weir	Junction City Weir	Trinity River Hatchery	Spawner survey
Grilse a/	31	51	377	5
Total	774	4,607	14,282	532
Percent grilse	4.0%	1.1%	2.6%	0.9%
a/ Spring chinook salmon < 50 cm FL are considered grilse based on a post-season analysis of CWT returns.

TABLE 2. Numbers and percentages of spring chinook salmon grilse observed in the spawner survey and at three fixed locations in the Trinity River, 1988.

FIGURE 3. Fork length distribution, in 2-cm increments, of spring chinook salmon measured in the 1988 upper Trinity River spawner survey (N = 532).

FIGURE 4. Fork length distribution, in 2-cm increments, of fall chinook salmon measured in the 1988 upper Trinity River spawner survey (N = 774).

	Willow Creek Weir	Junction City Weir	Trinity River Hatchery	Spawner Survey
Grilse a/	570	252	4,752	71
Total	2,812	2,110	22,104	774
% Grilse	20.3%	11.9%	21.5%	9.2%
a/ Fall chinook < 57 cm FL are considered grilse based on a post-season analysis of CWT returns.

TABLE 3. Numbers and percentages of fall chinook salmon grilse observed in the spawner survey and at three fixed locations in the Trinity River, 1988.

Sex Composition

Chinook Salmon

We sexed 1,753 adult chinook salmon during the survey. Adult females outnumbered adult males at a ratio of 1.73 : 1.0 (63.4% females). The preponderance of adult females has been noted in all previous surveys and has ranged from 73.6% to 50.3% (Moffett and Smith 1950, Gibbs 1956, Weber 1965, LaFaunce 1965; Rogers 1970, 1973, 1981; Smith 1975, and Stempel 1988) (Table 4). The reason for the predominance of adult females probably results from the tendency of males to return as grilse at greater rates than females, thereby decreasing the number remaining to return as adults.

		Adult Chinook
Year	Reference	Male	Female	Total	Percent male	Percent female
1942 to 1945	Moffett/ Smith, 1950	201	364	565	35.6	64.4
1955	Gibbs, 1956	1,769	1,789	3,558	49.7	50.3
1956	Weber, 1965	3,149	3,657	6,806	46.3	53.7
1963	LaFaunce, 1965	1,419	2,008	3,427	41.4	58.6
1968	Rogers, 1970	1,244	1,551	2,795	44.5	55.5
1969	Smith, 1975	1,054	1,791	2,845	37.0	63.0
1970	Rogers, 1973	527	556	1,083	48.7	51.3
1971	Rogers, 1982	1,704	1,987	3,691	46.2	53.8
1987	Stempel, 1988	1,182	3,299	4,481	26.4	73.6
1988	Present study	642	1,111	1,753	36.6	63.4

TABLE 4. Sex composition of adult chinook salmon observed in periodic surveys of the Trinity River, 1942 through 1988.

Coho Salmon

Of 468 coho for which sex was determined, 42.3% (198/468) were females (Appendix 2). Coho fork lengths were not taken, so adult-only sex ratios (excluding grilse) could not be determined. It is likely that the preponderance of male coho salmon is the result of the inclusion of male grilse in the total counts of coho recovered.

Prespawning Mortality

Chinook Salmon

Of the 889 female chinook carcasses checked for spawning condition, 44.9% (399) still retained the majority (>50%) of their egg mass (Appendix 1). According to field personnel, most of these actually still contained 90% or more of their egg mass. Spring chinook had a higher overall prespawning mortality rate (63.5%) than fall chinook (42.9%), probably related to the added stress imposed by the extended time spent in the river. There was a tendency for prespawning mortality to decrease through time ranging from 75% early in the survey to approximately 30% in the last weeks (Figure 5, and Appendix 1). This is a lower spawning success rate than reported in any of the previous studies (Table 5).

FIGURE 5 Female chinook salmon prespawning mortality rates observed in the 1988 upper Trinity River spawner survey.

Coho Salmon

We checked 180 female coho for spawning condition. The overall prespawning mortality rate was 25.6% (46/180) (Appendix 2). No previous data are available for coho prespawning mortality in the Trinity River.

		FEMALE CHINOOK
Study year	References	Spawned	Unspawned	Total	Percent unspawned

TABLE 5. Female chinook salmon prespawning mortality rates, observed in periodic surveys of the upper Trinity River, 1955 through 1988

Salmon Distribution

For purposes of comparison with other study years, distribution is presented based on the four-zone system used in all but two of the previous studies. We were only able to evaluate the distribution of salmon in the main-stem Trinity River this year, due to staffing constraints caused by hiring delays.

Chinook Salmon

Of 5,662 chinook carcasses we recovered this season, 46.1%, 49.7%, 3.0%, and 1.2% were from Zones 4, 5, 6, and 7, respectively (Table 6). We recognized that carcass counts alone could not be used to accurately describe distribution because recovery efficiency varies based on observation conditions unique to each zone. Therefore, the percentage of flags recovered from each zone was used to determine the recovery efficiency of that zone. For example, 88 (18.0%) out of the 490 flags placed on chinook salmon in Zone 4 were subsequently recovered (Table 6). Based on the total number of chinook recovered and the recovery efficiency rates for each zone, 40.2%, 47.8%, 8.4%, and 3.7% of the chinook salmon spawned in Zones 4, 5, 6, and 7, respectively (Table 6).

Zone	Number flagged	Total a/ observed	Flags recovered	Flag recovery efficiency	Estimated total	Proportional spawner distribution
4 b/	490	2,612	88	18.0%	14,511	40.2%
5 c/	486	2,815	79	16.3%	17,270	47.8%
6 d/	72	169	4	5.6%	3,018	8.4%
7 e/	20	66	1	5.0%	1,320	3.7%
All zones		5,662			36,119
a/ Total chinook observed exclusive of flag recoveries. b/ From Lewiston Dam to Old Bridge in Lewiston (3.2 km). c/ From Old Bridge to Douglas City Bridge (25.7 km). d/ From Douglas City Bridge to Canyon Creek mouth (24.1 km). e/ From Canyon Creek mouth to North Fork Trinity mouth (11.3 km).

TABLE 6. Chinook salmon spawner distributions, by river zone, in the Trinity River below Lewiston Dam during 1988

A potential source of error for this distribution estimate lies in the assumption that flagged chinook were recovered only in the zone in which they were originally flagged. If flagged fish drifted into, and were recovered in downstream zones, it would have tended to increase the efficiency estimate in the recovery zone while decreasing the estimate in the flagging zone. We intend to stratify flag coloring by zone and by week, next year.

Chinook salmon spawning distributions in the main stem Trinity River have changed dramatically since 1965, as spawning concentrations have tended to move further up the river (Figure 6, and Table 7). This is probably the direct result of progressive, downstream spawning-bed deterioration through sedimentation. Large amounts of decomposed granite are deposited into the river from various sources, most notably Grass Valley Creek (see Figure 1). Controlled flows from Lewiston Dam prevent the large flushing flows necessary to transport these sediments downstream. Through time, this has resulted in fewer productive spawning beds in the lower sections of the river.

FIGURE 6. Chinook salmon spawning distributions in the main stem Trinity River, by river zones, observed in periodic surveys between 1955 and 1988.

TABLE 7. Percentages of total chinook salmon spawning occurring in each zone of the main stem Trinity River in years of record from 1955 through 1988. ^a/

Coho Salmon

Our estimates of total coho salmon in each zone were computed based on actual numbers observed divided by the recovery efficiencies developed from chinook salmon flag recoveries. Like chinook salmon, spawning coho tended to be most concentrated in the upper river (Table 8), with the greatest proportion of the total run utilizing Zone 4.

Marked Salmon Recovery

Coded-wire Tags

We recovered 121 Ad-clipped chinook salmon in the spawner survey. Based on analyses of their CWTs, 52 were spring chinook, 44 fall chinook salmon, and 25 fish had shed their tags (Appendix 3). All CWT recoveries were tagged at Trinity River Hatchery (TRH).

The percentage of Ad-clipped fish in the spawner survey is best estimated by considering only condition-one fish, as Ad-clips could not be reliably determined on fish in advanced decay (ie. condition two). The percentage of Ad-clipped chinook in the condition-one population was 7.7% (37/479) for spring chinook and 3.0% (21/705) for fall chinook.

Zone	Total observed	Observation efficiency a/	Estimated total	Proportional spawner distribution
4	401	18.0%	2,228	60.4%
5	193	16.3%	1,184	32.1%
6	10	5.6%	179	4.8%
7	5	5.0%	100	2.7%
All zones	609		3,691
a/ Observation efficiency equals the total recovery rate of flagged chinook carcasses in each zone.

TABLE 8. Coho salmon spawner distributions, by river zone, in the Trinity River below Lewiston Dam during 1988.

Program tags

We observed Program tags on 53 spring chinook, 159 fall chinook, and 50 coho in the spawner survey. Forty-five of the spring chinook were tagged at Junction City Weir and eight were tagged at Willow Creek Weir. For fall chinook recoveries, 93 were from Junction City Weir, 55 from Willow Creek, 4 were recovered from both Junction City and Willow Creek weirs, and 7 were from the Klamath River mouth. Of the 50 coho observed, 14 were from Junction City Weir, 33 from Willow Creek Weir, and 3 were captured at both weirs.

As with Ad-clips, only condition-one, Program-marked fish were used to determine the overall percentage of tags in the spawner survey. Totals of 3.4% (40/1,184) and 2.0% (24/1,184) of the condition-one chinook salmon recovered in the spawner survey were tagged at Junction City and Willow Creek weirs, respectively. For comparison, tag recovery rates at TRH of Program-marked fish were similar, at 3.8% (1,380/36,386) and 2.1% (747/36,386) for chinook salmon tagged at Junction City and Willow Creek Weir, respectively.

Incidence of Hatchery-produced Chinook Salmon

The incidence of hatchery-produced chinook among the carcasses seen in the spawner survey was determined by comparing the rate of Ad-clipped (hatchery-marked) chinook at the various locations within the river.

Spring Chinook Salmon

The percentage of Ad-clipped spring chinook observed at various locations in the Trinity River basin below Lewiston Dam ranged from 7.7% to 13.0% (Table 9).

	Spring Chinook				Fall Chinook
Location	Ad-clips	Total	Percent Ad-clips		Ad-clips	Total	Percent Ad-clips
Willow Creek Weir	64	774	8.3		310	2,812	11.0
Junction City Weir	531	4,607	11.5		225	2,110	10.7
Trinity River Hatchery	1,858	14,282	13.0		4,752	22,104	21.5
Spawner survey a/	37	479	7.7		21	705	3.0
a/ Only condition one chinook carcasses are included in counts.

TABLE 9. Numbers and percentages of total observed Ad-clipped spring and fall chinook salmon at various locations in the Trinity River, 1988.

Since most (> 98%) of the spring chinook salmon recovered at TRH are estimated to be of hatchery origin (Bill Heubach, Assoc. Fishery Biologist, CDFG, pers. comm., based on expansions of CWT recoveries), we assume that the 13.0% Ad-clip rate for spring-run observed there represents the fraction that would occur in a population of 100% TRH-origin chinook. It is not possible to use the original hatchery Ad-clip rates to determine the proportion of hatchery vs. wild fish returning to TRH, because the proportion of hatchery chinook groups that are Ad-clipped varies annually, and returns to TRH are a varying mix of brood years. In addition, different brood years may have experienced different rates of mortality among marked vs. unmarked fish. Since our survey recovered Ad-clipped fish at only 59.2% (7.7/13.0) of the Ad-clip rate observed at TRH, we estimated that 59.2% of the spring chinook observed in the survey were of TRH origin while the remaining 40.2% were naturally produced.

Fall Chinook Salmon

The Ad-clip percentage of fall chinook salmon was lowest in the spawner (carcass) survey (3.0%) followed by Junction City Weir (10.7%), Willow Creek Weir (11.0%), and TRH (21.5%) (Table 9). The percentages observed at the various recovery sites, for both fall-run and spring-run chinook salmon, were probably the result of hatchery-produced (Ad-clipped) fish homing to the hatchery. Since naturally-produced chinook salmon also spawn in the lower main stem or its tributaries, the percentage of hatchery-produced chinook in the population probably increases further upstream, and would be highest at the hatchery. Ad-clip rates in the spawner survey may have been less than at downstream weirs, as the weirs captured a fraction of all upstream migrants, hatchery and natural fish, while the spawner survey emphasized in-river spawners which would be more likely to be naturally produced fish.

Since most (> 94%) of the fall chinook recovered at TRH are estimated to be of hatchery origin (Bill Heubach, Assoc. Fishery Biologist, Calif. Dept. Fish Game, pers. comm.), we assumed that the 21.5% Ad-clip rate for fall-run observed at TRH represents the fraction that would occur in a population of 100% hatchery produced chinook. Since only 3.0% of the fall chinook salmon in the spawner survey were Ad-clipped, we estimated that 14.0% (3.0/21.5) were of hatchery origin, while the remaining 86.0% were naturally produced. In 1987, using the same method, Stempel (1988) reported that 41% of the fall chinook in the spawner survey were naturally produced.

There are several assumptions which could be potential sources of error in using the aforementioned method to determine the incidence of hatchery fish spawning in the river. We assume that field personnel actually observed all possible Ad-clips in the survey. The recognition of an Ad-clip, even on fish in relatively good condition, can be difficult. We are also assuming that the probability of observing/ recovering an Ad-clipped fish is the same in the survey as at the hatchery, and, most importantly, that Ad-clip:unmarked ratios of hatchery fish are the same in the spawner survey as at TRH. Since different chinook salmon release groups are Ad-clipped at different rates, this last assumption is only valid if the various CWT groups occur in the spawner survey in the same proportions as among the fish recovered at TRH.

RECOMMENDATIONS

This is the first year of a multi-year effort of spawner surveys in the upper Trinity River basin. 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 1989-90.

2. Major tributaries, including the North Fork Trinity River, Canyon Creek, Browns Creek, Reading Creek, Weaver Creek, Rush Creek, and Grass Valley Creek, should be systematically surveyed to determine to what extent salmon spawning occurs.

3. Prespawning mortality of female chinook should be closely monitored to determine if it is a continuing problem.

4. Flags placed on carcasses should be distinctive for each zone to account for drifting of flagged carcasses into downstream zones.

5. Survey efforts should be increased, in an effort to recover more salmon which were both spaghetti tagged and Ad-clipped, which will allow us to assess the survey's recovery efficiency of Ad-clipped fish, by comparing the rate at which spaghetti tagged fish observed for the second time are noted as having an Ad-clip. A reliable estimate of Ad-clipped fish in the survey is necessary to more accurately determine the incidence of hatchery-produced chinook salmon which spawn naturally.

LITERATURE CITED

Gibbs, E. D. 1956. A report on king salmon, Oncorhynchus tshawytscha, in the upper Trinity River, 1955. Calif. Dept. Fish and Game, Anad. Fish. Admin. Rep. No. 56-10. 14 p. (Mimeo.).

LaFaunce, 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. (Mimeo.).

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.

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. (Mimeo.).

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. (Mimeo.).

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. (Mimeo.).

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. (Mimeo.).

Stempel, M. 1988. Chinook salmon spawning survey in the upper Trinity River during the fall of 1987. USFWS file report. Available from USFWS - Fisheries Assistance Office, 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. 34p.

APPENDICES

ANNUAL REPORT

TRINITY RIVER BASIN SALMON AND STEELHEAD MONITORING PROJECT

1988-1989 SEASON

by

Mark Zuspan

ABSTRACT

Staff of the California Department of Fish and Game's Trinity Fisheries Investigations Project conducted a trapping and coded-wire tagging operation for naturally-produced, juvenile chinook salmon (Oncorhynchus tshawytscha), on the upper main stem Trinity River from January 19 through May 12, 1989. This report summarizes juvenile chinook salmon catch-per-unit-effort and fork length data collected during the study period, and provides summaries of other juvenile salmonids trapped coincidentally.

We trapped 24,874 chinook salmon, 916 coho salmon (Oncorhynchus kisutch), 555 steelhead trout (O. mykiss), and 26 brown trout (Salmo trutta) juveniles during the study.

We implanted coded-wire tags into 22,044 juvenile chinook salmon, a subsample of which ranged in size from 32 to 75 mm fork length. After adjusting for tagging mortality, tag shedding, and poor fin clips, we effectively coded-wire tagged and released 15,704 juvenile chinook salmon.

JOB OBJECTIVE

To capture, mark (adipose fin-clip), tag (coded-wire), and release representative groups (up to 100,000 fish/group) of naturally produced chinook salmon fry/fingerlings in the main stem Trinity river and/or selected Trinity River tributary streams. These fish will be sampled subsequently, by other projects, to determine their survival and contribution as adults to the ocean and river fisheries, and spawning escapements.

INTRODUCTION

The Trinity River system, in Northern California, is a major producer of chinook for the Klamath River basin. During the past 11 years, an average of 53.7 % of the Klamath River basin chinook spawning escapement occurred in the Trinity River basin above Willow Creek (Appendix 1). Knowledge of fry/fingerling-to-adult survival, harvest, and spawning escapement of Trinity River basin chinook salmon is crucial to their effective management.

U. S. Public Law 98-541, enacted in 1984, has resulted in a major effort to restore the fishery resources in the Trinity River basin to pre-Trinity-Project conditions. Emphasis for this effort is placed on naturally produced fish. Survival, catch, and escapement data for these fish will help to evaluate the effectiveness of these restoration efforts.

Previous juvenile-chinook-salmon, coded-wire-tagging studies in the Trinity River basin have focused on hatchery-produced chinook salmon and made references to naturally produced chinook based on those results (Heubach and Hubbell 1979, Heubach 1980, Maria and Heubach 1981, 1984a, 1984b, 1984c).

In this study, California Department of Fish and Game (CDFG) Trinity Fisheries Investigations Project personnel trapped, coded-wire tagged (CWT), and released naturally-produced, juvenile chinook salmon. Subsequent studies of these fish as adults, by other projects of the CDFG's Klamath-Trinity Program, will be used to determine survival, harvest, and spawning escapement for this important component of the Trinity River basin chinook stocks.

METHODS

Trapping

Our trapping site was located on the main stem Trinity River at river km 130, approximately 3.2 km upstream of Junction City (Figure 1). The site was chosen for its relatively wide and shallow characteristics, and its position upstream of major chinook spawning tributaries. All chinook salmon trapped at this site were assumed to have originated in the main stem Trinity River.

FIGURE 1 Map of the Trinity River below Lewiston Dam, showing the trapping site used in 1989.

Our trapping apparatus consisted of one to three fyke nets, measuring 2.7 m wide, by 1.8 m high, by 7.6 m long, leading to dual live boxes. Fyke nets were attached, at the mouth, to a 2.5-cm (1-in) diameter galvanized pipe frame, of the same dimensions as the net mouth, which was connected by ropes to a 95-mm (3/8-in) cable stretched across the river approximately 3.7 m above the surface. In early May, a floating rotary trap (screw trap), designed by the Oregon Department of Fish and Wildlife, was connected to the cable and fished along with the fyke nets. The basic trap design was a rotating cone suspended within a floating framework that lead to a live box. The cone was 2.7 m long with a 2.4-m opening, which faced upstream, and tapered to a 71 cm entrance into an aluminum live box. Water flow against the fiberglass vane, which spiralled through the cone, turned the cone within its framework. Fish entering the cone were enclosed within the spiral vane and guided into the live box. The trap captured fish in the upper 1.2 m of the water column and sampled a cross sectional area of approximately 9.1 m . The screw trap was thought to be more effective trapping in high flows than fyke nets.

The primary objective of the trapping effort was to capture up to 100,000 juvenile chinook salmon for coded-wire tagging. All fish trapped were counted and a subsample of each species was measured to the nearest mm fork length (FL).

Tagging

The tagging site was located adjacent to the trapping site. Tagging was conducted inside a 4.9-m x 4.9-m canvas tent. Because of the remote nature of the site, a generator was used to supply the electrical needs (tagging machines, pumps, lights) of the operation. A gasoline-powered pump was used to supply river water for tagging purposes.

Captured chinook were anesthetized with tricaine methanesulfonate (MS222), their adipose fin removed, and a CWT implanted. Tag injectors and quality control devices were purchased from Northwest Marine Technology . Because of the small size of the fish captured, 1/2-length tags were used.

A sample of 100 fish from each day's tagging was held for quality control and the remainder released back into the river at the tagging site. Fish in the quality control sample were put into holding cages and, after a minimum of 24 hours, checked for mortality, tag retention, and adipose fin-clip (Ad-clip) effectiveness. Tag retention was determined by passing fish through the electronic tag (metal) detector and Ad-clip effectiveness was determined by direct examination.

When adequate numbers of chinook salmon were available, two tagging machines were employed, otherwise only one was used.

RESULTS

Trapping

Trapping began January 19, 1989 and continued on a weekly basis until March 20, when catch rates increased and daily trapping was instigated. High flows from March 2 through March 19 and April 28 through May 31, 1989 (1,000 - 2,000 ft/sec) made trapping impossible or largely ineffective during these periods.

Chinook salmon

We captured 24,874 chinook salmon this season. Weekly average catch-per-night peaked in late February, at 358 fish per trap, and again early April, at 519 fish per trap (Figure 2, and Appendix 2). The bimodal catch distribution may reflect peak spring and fall chinook salmon emigrations.

FIGURE 2. Weekly average catches per trap per night of juvenile chinook salmon in the main stem Trinity River (river km 130), during 1989.

We measured FLs of 3,181 chinook salmon during the trapping season. These fish ranged in FL from 29 to 85 mm. The portion of the aforementioned subsample which represented CWT fish ranged in FL from 32 to 75 mm. Weekly average FL for all fish (CWT and untagged) increased from 36.4 mm to 54.6 mm during the study period (Figure 3, and Appendix 2).

FIGURE 3. Weekly average fork lengths (mm) of juvenile chinook salmon captured in the main stem Trinity River (river km 130), during 1989.

Other Salmonids

Other salmonids trapped during the season included 916 coho salmon, 555 steelhead trout, and 26 brown trout (Appendix 2).

Both yearling and young-of-the-year coho salmon were trapped. Young-of-the-year were first noted March 20, 1989. Previously, only yearlings were trapped.

Tagging

Tagging operations commenced March 29, 1989 and continued through May 12, 1989. During this period, 22,044 chinook salmon were Ad-clipped, CWT and released.

Independent, non-overlapping estimates of tagging mortality, tag shedding, and poor Ad-clips, based on the quality control groups, are 10.90%, 12.32%, and 5.54% respectively. Based on these estimates, we effectively marked and released 15,704 juvenile chinook salmon.

DISCUSSION

The chinook salmon catch this season was inadequate to meet our 100,000 fish tagging goal. This was primarily the result of high main stem flows in early March, and again in late April through May 1989, which made trapping with fyke nets ineffective. The screw trap, put into operation in early May, appeared to be effective in

trapping juvenile chinook during high flows. If high flows are encountered next trapping season, at least three screw traps should be employed to catch adequate numbers of juvenile chinook for tagging.

Mortality, tag shedding, and poor Ad-clipping of CWT fish should be minimized to increase the number of effectively tagged chinook. A newly designed and constructed tagging trailer should be available for the 1990 tagging season. The trailer, with its adequate lighting, heating, and water supply, should help to increase tagging efficiency.

RECOMMENDATIONS

1. Job 2 activities should be continued in FY 1989-90.

2. A tagging trailer should be used to increase the efficiency of coded-wire tagging crews.

3. Screw traps should be employed during high flows to more effectively capture juvenile chinook salmon.

LITERATURE CITED

Heubach, B., and P. Hubbell. 1979. FY 1978 Progress Report. Task V. Salmon Tagging and Release Monitoring. pp. 1-5 In: Paul M. Hubbell (ed.), Evaluation Report--FY 1978. Trinity River Basin Fish and Wildlife Task Force Priority Work Item No. 5. January 1979. 65 pp. Available from Calif. Dept. Fish and Game, Inland Fish. Div., Sacramento, CA. 95814.

Heubach, B. 1980. FY 1979 Progress Report. Task V. Salmon Tagging and Release Monitoring. pp. 75-79 In: Paul M. Hubbell (ed.), Progress Report. Fishery Investigations - Trinity River. Trinity River Basin Fish and Wildlife Task Force Priority Work Item No. 5. September 1980. 141 pp. Available from Calif. Dept. Fish and Game, Inland Fish. Div., Sacramento, CA. 95814.

Maria, D., and B. Heubach. 1981. FY 1980 Progress Report. Task V. Salmon Tagging and Release Monitoring. pp. 7-12 In: Paul M. Hubbell (ed.), Progress Report. Fishery Investigations - Trinity River. Trinity River Basin Fish and Wildlife Task Force Priority Work Item No. 5. Tasks II, V and VII. December 1981. 23 pp. Available from Calif. Dept. Fish and Game, Inland Fish. Div., Sacramento, CA. 95814.

Maria, D., and B. Heubach. 1984a. FY 1981 Progress Report. Task V. Salmon Tagging and Release Monitoring. pp. 6-15 In: Paul M. Hubbell (ed.), Progress Report. Fishery Investigations - Trinity River. Trinity River Basin Fish and Wildlife Task Force Priority Work Item No. 5. Tasks II, V, VII. October 1984. 24 pp. Available from Calif. Dept. Fish and Game, Inland Fish. Div., Sacramento, CA. 95814.

Maria, D., and B. Heubach. 1984b. FY 1982 Progress Report. Task V. Salmon Tagging and Release Monitoring. pp. 5-13 In: Paul M. Hubbell (ed.), Progress Report. Fishery Investigations - Trinity River. Trinity River Basin Fish and Wildlife Task Force Priority Work Item No. 5. Tasks II, V. November 1984. 13 pp. Available from Calif. Dept. Fish and Game, Inland Fish. Div., Sacramento, CA. 95814.

Maria, D., and B. Heubach. 1984c. FY 1983 Progress Report. Task V. Salmon Tagging and Release Monitoring. pp. 1-11 In: Paul M. Hubbell (ed.), Progress Report. Fishery Investigations - Trinity River. Trinity River Basin Fish and Wildlife Task Force Priority Work Item No. 5. Task V. November 1984. 11 pp. Available from Calif. Dept. Fish and Game, Inland Fish. Div., Sacramento, CA. 95814.

APPENDICES

Appendix 1. Klamath River basin fall chinook salmon spawning escapement estimates, 1978 -1988.

Appendix 2. Trinity River juvenile salmon trapping sumnary, January 19 through May 12, 1989.

ANNUAL REPORT

TRINITY RIVER BASIN SALMON AND STEELHEAD MONITORING PROJECT

1988-1989 SEASON

by

Terry J. Mills and Carrie E. Wilson

ABSTRACT

During the 1988-89 spawning season, the California Department of Fish and Game's Natural Stocks Assessment Project conducted adult steelhead (Oncorhynchus mykiss) spawning stock surveys on twelve streams tributary to the South Fork Trinity River (SFTR) and Hayfork Creek. High, turbid streamflows hampered survey efforts during this season, and prevented any valid estimation of run size or relative distribution of spawners in the basin.

We trapped 227 upstream migrant adult steelhead at Sandy Bar weir on the lower SFTR, between September 22 and November 13, 1988. No hatchery-marked fish were observed. The run increased through the week of November 3 - 13, at which time high flows prevented further trapping.

Based on the results of our creel survey, an estimated 1,579 anglers fished for adult steelhead within the SFTR basin during the 1988-1989 season. An estimated total of 65 adult and 29 juvenile steelhead were landed, and angler harvest rate based on tag returns was estimated to be 5.9%.

We collected scales from 227 adult and 250 juvenile steelhead. Thirty-two sets of adult and 65 sets of juvenile steelhead scales were read and interpreted for indications of various life history characteristics.

We monitored juvenile steelhead emigration from the upper SFTR basin and the Hayfork Creek basin, capturing 314 juvenile steelhead in the SFTR and 5,801 juvenile steelhead in Hayfork Creek. Age 0+ emigration peaked between May 21 and June 1, 1989.

JOB OBJECTIVES

1. To determine the size, composition, distribution and timing of the adult steelhead runs in the South Fork Trinity River basin.

2. To determine the angler harvest of adult steelhead in the South Fork Trinity River basin.

3. To determine the life history patterns of the South Fork Trinity River basin steelhead stocks.

4. To determine the seasonal use made by juvenile steelhead of various habitat types within selected South Fork Trinity River tributaries.

5. To describe relationships between habitat parameters and seasonal juvenile steelhead standing crops.

INTRODUCTION

The life histories of steelhead populations within the South Fork Trinity River (SFTR) basin are of concern because little data are available regarding juvenile steelhead life history patterns, adult steelhead run sizes, spawner distributions, sport fishery yields and harvest rates. The SFTR basin was severely impacted by the 1964 flood, which caused spawning and rearing habitats within the basin to be severely damaged or, in some instances, lost. A combination of human activities (such as road construction, timber harvest, and recreation) and natural events (such as wildfire and flooding) continue to curtail steelhead production within the basin. Restoration of salmon and steelhead habitat within the basin is a high priority for the Trinity River Basin Fish and Wildlife Task Force, the U. S. Forest Service ([USFS] Shasta-Trinity National Forest), and the California Department of Fish and Game (CDFG). These restoration efforts will be guided by knowledge of steelhead habitat requirements and life histories.

METHODS

To assess the timing of the adult steelhead run into the SFTR, this study used steelhead trapping data collected by CDFG personnel of the Natural Stocks Assessment Project, who operated a weir during the late summer and fall of 1988 (Sept. 27 to Nov. 14) at Sandy Bar on the lower SFTR, situated at river km 2.4 (Figure 1). Each steelhead captured was examined for adipose fin-clips (Ad-clips), tags, gill-net and hook scars, measured to the nearest cm fork length (FL), and its sex recorded. Gill-net scars were classified as nicks in the leading edges of dorsal and pectoral fins, sometimes combined with vertical white scars on the head of each steelhead. Hook scars were classified as pierced holes or tears in a fish's jaws. Healed hook scars were deemed to be of ocean origin, and fresh ones of freshwater origin. Predator scars were classified as inverted 'V' shaped marks, usually on the underbody. Other marks observed were classified as of unknown origin. All taggable fish caught at the weir were tagged with $10 reward tags (no non-reward tags were used) to estimate angler harvest rates from reward tag returns, and with the intention of computing a Petersen population estimate (Ricker 1975) based on the ratio of tagged to untagged fish observed in the creel census. We did not tag fish which had been excessively stressed by the weir capture and handling process, or those which appeared in generally poor physical condition, to avoid excessive tagging mortality.

Figure 1 Sampling and survey sites on the South Fork Trinity River.

A scale sample was removed from the left side of all weir-caught fish, in an area slightly posterior to the anterior insertion of the dorsal fin, just above the lateral line. Each scale sample was placed in a coin envelope and labeled with the collection date, collection site, and the sex and FL (in cm) of the fish.

The scales were later processed in the lab. Each adult scale sample was cleaned, dried, then mounted between two glass microscope slides. Scale samples from juvenile steelhead did not usually require cleaning. The cleaning process involved soaking scales in distilled water to soften them. Softened scales were rubbed between thumb and forefinger to remove debris. If debris persisted, scales were soaked in a 5% detergent solution made up with distilled water, and then rubbed again, as mentioned previously. Softened tissue and debris that continued to adhere to scales after these cleaning processes was peeled off using blunt-tipped forceps. Adult and juvenile steelhead scales were read using a 42x microfiche reader. All adult steelhead scales were read a second time by a different analyst, but juvenile scales were only spot checked. A training period of initial scale readings was undertaken to allow the readers to become familiar with the variety of steelhead life history patterns, and to develop the skills required to competently analyze steelhead scales. Scale parameters recorded were presence of half-pounder and spawner checks, location and number of freshwater and marine annuli, number of freshwater circuli, distance measurements to each annuli and to the point identified as ocean entry. Juvenile scales were similarly read. Data were recorded and then entered into a computer database.

Steelhead spawner distribution and tributary entry timing were examined by CDFG personnel on foot surveys of spawning areas during the spawning period. These areas included: i) tributaries of the lower SFTR drainage near its confluence with the main-stem Trinity River, ii) the upper SFTR drainage in the vicinity of the town of Hyampom (Hyampom area), and iii) the Hayfork Creek drainage (Figure 1). Specific creeks surveyed were chosen primarily to replicate areas examined in previous CDFG surveys (Miller 1975; Rogers 1972, 1973), and secondarily to cover creeks which may have historically attracted spawning fish, but were not covered in previous surveys. The latter creeks were chosen after consultation with USFS biologists. Stream sections were surveyed during the spawning season when weather, flow, and turbidity patterns permitted successful survey.

We estimated the sport harvest rate from the percent of $10 reward tags returned by anglers, based on the following assumptions: i) a 100% response rate by anglers, ii) that all tagged fish caught in the sport fishery were recognized as such by the anglers, iii) no tags were shed, and iv) there was no differential mortality between tagged and untagged fish.

We estimated the total sport catch of steelhead within the SFTR basin from a systematic creel census, conducted from November 19, 1988 through March 13, 1989. Our survey area was divided into two sections. The lower section extended from the confluence of the SFTR with the main stem Trinity River upstream for a distance of 22.2 km (Figure 1). The upper, Hyampom, section extended through Hyampom Valley from river km 32.7 to river km 48.8 (Figure 1). These two sample sections cover the river reaches fished by the majority of anglers, as public access is limited outside of these two areas, due to the lack of public roads. Angler access sites in each section were identified prior to the survey period. The creel survey was further stratified by standard (7 day) week [wk] (Appendix 1), day (weekend/weekday), and time (am/pm) periods. On days that were not censused, estimates were made for each stratum using average values for that stratum on similar days, during similar time periods (ie., for a missing weekday evening survey: mean of weekday pm's in that standard week). Estimated and actual data were combined for season totals. During the survey, clerks followed a set route based on a predetermined schedule, and examined each access site for anglers. Anglers observed fishing during the survey periods were contacted and interviewed for hours fished that day, success, angling method, and county or state of origin. Sport-caught steelhead were measured (FL, cm) and examined for Ad-clips and external tags. The numbers were recorded for all tags seen, and fish sex determined. Scale samples were taken from creeled fish, in the same manner as for fish from Sandy Bar Weir. We classified steelhead < 25 cm (FL) as juveniles, > 25 cm and < 35 cm as half-pounders, and > 35 cm as adults (Kesner and Barnhart 1972).

We determined juvenile steelhead emigration patterns from trapping at two sites within the SFTR basin; in lower Hayfork Creek, within 305 m upstream of its confluence with the SFTR, and in the SFTR upstream of its confluence with Hayfork Creek, within 0.4 km either side of Hyampom Rd. bridge (Figure 1). Juvenile steelhead were captured using fyke nets attached to traps. The nets were constructed of 1.3-cm nylon mesh, had a 1.8 m x 2.4 m opening and extended 10.1 m to the trap at the terminal end. Each trap was constructed of marine plywood and hardware cloth, measured 0.8 m x 1.2 m at the opening and were 0.5 m deep. One or two fyke-net traps were placed in the river or stream overnight, for 16-24 hour periods, and examined the following morning. Captured fish were identified to species and enumerated. A systematically collected subsample of 50 individuals, maximum, of each species was measured for FL (mm), daily. Scale samples were systematically taken from a maximum of 10 steelhead each sampling day. In each case, respectively, the samples consisted of the first 50 or 10 individuals removed from the traps each day.

RESULTS AND DISCUSSION

Adult Steelhead Distribution in the SFTR Basin

Our adult steelhead spawning surveys were conducted on tributaries located within the lower SFTR basin, the upper SFTR's Hyampom section, and the Hayfork Creek drainage between April 6, 1989 and May 27, 1989. Heavy rains and resultant high, turbid streamflows prevented CDFG crews from accessing many stream reaches and from making visual surveys of areas they could reach, thus no surveys were conducted in March, as originally intended. Unfortunately, much steelhead spawning activity had already taken place by the time the field surveys began in April.

Lower SFTR Section Tributaries

Madden Creek.

We surveyed Madden Creek on April 13, 1989. The survey covered the lower 0.8 km from the mouth, upstream. Suitable steelhead spawning areas were observed, but, because of high flows, individual redds and fish were difficult to see, and could not be accurately counted.

Hyampom Section Tributaries

Eltapom Creek

We surveyed Eltapom Creek on May 22, 1989, from its confluence with the SFTR upstream 1.2 km to a 4.5 m high natural falls, which was a barrier to further spawner migrations. Stream conditions were excellent for observing steelhead and redds, and we saw two adult steelhead. The survey occurred late enough in the year that some young-of-the-year (YOY) steelhead had already emerged from the spawning gravels.

Big Creek.

We surveyed Big Creek on May 1, 1989, from its confluence with the SFTR upstream 0.4 km to a natural cascade barrier to further spawner migration. Water conditions were excellent for observing fish, however no fish or redds were seen.

Kerlin Creek.

We surveyed Kerlin Creek on May 2, 1989, from its confluence with the SFTR upstream 0.8 km to an area of cascades and debris barriers, which prevented upstream migration of adult steelhead. No redds, fish, suitable spawning areas or holding areas were seen.

Butter Creek.

We surveyed Butter Creek on April 18, 1989, from its confluence with the SFTR upstream 3.2 km to Butter Creek Falls, a barrier to further spawner migrations. Stream conditions for steelhead and redd observations were good, and we saw four steelhead redds. Spawning habitat and holding pools were limited, however.

Pelletreau Creek.

We surveyed Pelletreau Creek on April 19 for 0.5 km and May 1, 1989, for 1.2 km upstream of its confluence with the SFTR to a natural roughs area which formed a barrier to further migration. No redds or adult steelhead were seen on either occasion.

Hayfork Creek Tributaries

Olsen Creek.

We surveyed Olsen Creek on April 6, 1989, from its confluence with the SFTR upstream for 0.8 km to a complete debris dam, which was determined to be a barrier to further upstream migration. Three steelhead redds were seen within this lower area. USFS and CDFG personnel removed the barrier on April 10. The stream was surveyed again, on May 1, for a distance of 1.6 km above the former location of the debris dam. We saw two redds in this newly opened upper reach. Several YOY steelhead were also seen during the latter survey.

Big Creek.

We surveyed the upper and middle sections of Big Creek on May 16, 1989, and the lower section on May 17 for a total of 11.6 km. Stream conditions for observing adult steelhead and redds were good, and we saw one steelhead redd.

Carr Creek.

We surveyed the main reach of Carr Creek on April 22, 1989, from its confluence with Duncan Creek upstream to the West Fork of Carr Creek. Conditions for observing adult steelhead and redds were good. Spawning gravels and holding areas were limited and no steelhead or redds were seen.

Salt Creek.

We surveyed Salt Creek on May 29, 1989, from its confluence with Hayfork Creek upstream for 4.8 km. No adult steelhead or redds were seen. Because of the late timing of the survey, numerous YOY steelhead were present.

West Tule Creek.

We surveyed West Tule Creek on May 15, 1989, from its confluence with Hayfork Creek upstream for 3.2 km. Survey conditions were good, but no adult steelhead or redds were seen. Suitable spawning and holding areas were available within the surveyed area, however.

Rusch Creek.

We surveyed Rusch Creek on April 28, 1989, from its confluence with Hayfork Creek upstream for 1.6 km. Two debris barriers were noted within the survey section and spawning area was limited. No redds or adult steelhead were seen.

Summary

These steelhead spawner surveys were an attempt to emulate work done in the early 1970's (Miller 1975; Rogers 1972, 1973). Due to high flows and turbidity, which delayed access to spawning areas and the effectiveness of the visual surveys, respectively, the spawner surveys were inconclusive. The presence of YOY steelhead are indicative that adult steelhead had begun spawning prior to the start of the survey. Successful estimation of steelhead spawner distributions in future years will be dependant on our ability to access stream reaches and effectively survey them, which will be negatively affected by high streamflows and turbidity.

Adult Steelhead Run Timing in the SFTR Basin

During the period September 22, 1988, through November 13, 1988, we trapped and examined 227 adult steelhead at the weir operated at Sandy Bar in the lower SFTR. One hundred and nineteen of these fish were considered healthy enough to be tagged with $10 reward tags. Mean FL of the 227 steelhead examined was 61.7 cm and ranged from 46 cm to 83 cm. Nine fish (4.0%) had gill-net scars, 3 (1.3%) had freshwater hook scars, 15 (6.6%) had predator scars, and 15 (6.6%) had scars of unknown origin. None of the fish had Ad-clips, indicative of hatchery origins, or hook scars from the ocean fishery. Eight steelhead, tagged by CDFG personnel at the Willow Creek Weir on the main-stem Trinity River in 1988, were recaptured 6.1 km upstream at Sandy Bar Weir on the SFTR. Travel time between the capture sites ranged from 5 to 45 days (d), and averaged 18 d. One steelhead, tagged at Sandy Bar Weir in 1987, was recaptured 375 d later, in 1988. This fish had grown 5 cm FL from 53 cm FL, when tagged and released in 1987, to 58 cm FL, when recaptured in 1988. The first steelhead of the season was trapped on September 27, 1988. Numbers of steelhead trapped increased subsequently and peaked November 3, then tapered off through November 13, when high flows prevented further trapping for the season (Figure 2). During this 11-day, peak-entry period, 180 (79.3%) of the 227 steelhead examined during the whole season were trapped.

No weirs to trap outmigrant adults were operated within the Hyampom and Hayfork areas during this reporting period, as originally proposed. Due to high flows, CDFG personnel were not able to install them until May, which was too late to be of any value in sampling the majority of adult out-migrant steelhead. In future years, successful estimation of adult steelhead run size will be heavily dependent on our ability to situate and maintain a pair of weirs within the basin during high rainfall and flow periods.

Figure 2 Catches of upstream-migrant steelhead at Sandy Bar Weir (river km 2.4) on the South Fork Trinity River, fall 1988.

South Fork Trinity River Creel Survey

Creel survey work was conducted between November 19, 1988, and March 13, 1989, an interval of 115 d. We monitored the lower river survey section (Figure 1) for angler activity on a total of 79 d, and conducted a creel survey on 56 d of this period, when anglers were present. The upper river section was monitored on 112 d and a creel survey conducted on 82 d of this period. We determined that the lower river was "unfishable", based on flow or turbidity observations, for 23 (29.1%) of the days it was monitored, and the upper section for 40 (35.7%) of the days it was monitored.

Lower South Fork Trinity River Section Creel Census Data
Dates	Julian weeks	Number of anglers	Observed angler hours	Estimated number of anglers	Estimated angler hours	0bserved adult harvest	Estimated adult harvest	0bserved juvenile harvest	Estimated juvenile harvest
Nov. 19 -Dec.02	47-48	30	45.0	132	195.4	1	3	0	0
Dec. 03 - 16	49 -50	16	21.9	56	68.3	0	0	4	19
Dec. 17- 31	51 - 52	13	9.0	37	20.3	0	0	0	0
Jan. 01- 14	01 - 02	8	5.8	63	56.7	0	0	0	0
Jan. 15- 28	03 - 04	28	26.0	157	141.5	0	0	0	0
Jan. 29 -Feb 11	05 - 06	13	9.0	52	35.0	0	0	0	0
Feb. 12- 25	07 - 08	3	5.5	25	44.2	0	0	0	0
Feb. 26 -Mar. 11	09 - 10	0	0.0	0	0.0	0	0	0	0
Mar. 12- 25	11 - 12	1	1.0	3	3.3	0	0	0	0
	SUB- TOTALS	112	123.2	529	569.7	1	3	4	19

Upper South Fork Trinity River Section Creel Census Data
DATES	Julian weeks	Number of anglers of	Observed angler hours	Estimated number of anglers	Estimated angler hours	Observed adult harvest	Estimated adult harvest	Observed juvenile harvest	Estimated juvenile harvest
Nov. 19 - Dec. 02	47-48	36	86.0	292	646 4	3	14	1	6
Dec. 03 - 16	49-50	29	100.5	134	386.4	4	13	0	0
Dec. 17 - 31	51-52	1	1.5	4	6.2	0	0	0	0
Jan. 01-14	01-02	37	77.5	152	322.8	2	7	1	4
Jan. 15-28	03-04	63	118.5	238	458.7	5	22	0	0
Jan. 29 - Feb. 11	05-06	28	30.5	94	99.6	2	6	0	0
Feb. 12-25	07-08	18	21.;	90	106.4	0	0	0	0
Feb. 26 - Mar. 11	09-10	8	8.5	48	48.4	0	0	0	0
	SUB- TOTALS	220	444.5	1,050	2,074.9	16	62	2	10
	GRAND TOTALS	332	567.7	1,579	2,644.6	17	65	6	29

Table 1. South Fork Trinity River creel census data summary for the two sections censused in the 1988-89 season.

We interviewed 332 anglers during the census period, 112 (33.7%) within the lower census area and 220 (66.3%) within the upper census area (Table 1). We saw 17 adult steelhead in the catch, 1 in the lower river and 16 in the upper section. Based on data expansions of the various strata, an estimated 529 anglers within the lower section landed 3 adult and 19 juvenile steelhead, while an estimated 1,050 anglers in the upper section landed an estimated 62 adults and 10 juveniles. Two tagged steelhead were seen in the catch. One fish had been tagged October 5, 1988, at the Willow Creek Weir (main stem Trinity River) and recovered 87 d later on January 3, 1989. The other had been tagged November 6, 1988, at the SFTR Sandy Bar weir and recovered 72 d later on January 17, 1989. A sampling survey must recapture at least three or four tagged fish to be sure that a Petersen population estimate computed from it, is actually greater than zero (Ricker 1975, page 79). Since only one fish tagged at Sandy Bar Weir was recovered, it is not possible to make a Petersen population estimate of run size from this years creel survey data. Seven reward tags were returned by anglers indicating a 5.9% harvest rate (7 returned/119 tagged).

County of origin was tabulated for 324 anglers. The majority (86%) of the anglers fishing within the SFTR basin were from Trinity, Shasta and Humboldt counties (Table 2).

Generally, angling opportunities within the SFTR basin were limited this season, because heavy rainfall resulted in high flow and turbidity patterns. Furthermore, unusually cold weather in December curtailed angling activity, even though water clarity was relatively high.

County of Origin	Number (Percent)
Butte	2 (0.6)
Contra Costa	2 (0.6)
Fresno	4 (1.2)
Humboldt	60 (18.5)
Lassen	5 (1.5)
Sacramento	4 (1.2)
San Bernadino	3 (0.9)
Santa Barbara	4 (1.2)
Santa Clara	7 (2.2)
Shasta	31 (9.6)
Siskiyou	2 (0.6)
Sutter	3 (0.9)
Tehema	9 (2.8)
Trinity	188 (58.0)
TOTALS	324 (100.0)

Table 2 County of origin for anglers interviewed within the South Fork Trinity River Basin during the 1988-89 season.

Steelhead Life History Patterns

Steelhead life history patterns can be described from intensive analysis of scales, from both adult and juvenile fish. Initial efforts to read scales were preceded by an inventory of existing scales. These samples have been collected by CDFG personnel who conducted reconnaissance level creel surveys within the SFTR basin in 1981-1984, and operated a weir at Sandy Bar on the lower SFTR from 1984-1988. Some scales were collected this reporting period during the SFTR creel survey. The existing SFTR adult steelhead scale collection has 632 scale sets. Two hundred and fifty sets of juvenile, and 227 sets of adult steelhead scales were collected during this reporting period.

Initial scale reading was completed for 65 sets of juvenile, and 32 sets of adult scales. Ten (15.4%) of the 65 juvenile scale samples were from Age 0+, and 55 (84.6%) were from Age 1+ fish. Mean FL of these Age 1+ and 0+ juvenile fish, combined, was 93.7 mm and ranged from 61 to 131 mm. These juvenile steelhead exhibited a mean of 17 freshwater circuli, ranging from 5 to 26. The mean circuli count to the first freshwater annulus was 10, ranging from 7 to 17 circuli.

Because of difficulty in identifying the first freshwater annulus in adult scales, a more intensive effort was made to identify the location of the first annulus in Age 1+ and Age 2+ juvenile scales. Further difficulties in reading adult scales were encountered in aging fish with four or more annuli, and fish with spawning checks. Based on juvenile steelhead scales, the first annulus in adult scales is often preceded by a limited number of freshwater circuli. We are now examining the area located 8 to 12 circuli from the scale nucleus in adult scales to identify the first annulus.

Twenty-four (75.0%) of the 32 adult scale samples examined were from fish that had spent two years in fresh water prior to smolting, 6 (18.8%) were from fish who had smolted at Age 3, and age of smolting could not be identified for 2 (6.3%) of the scale samples. Three (9.4%) of the 32 adult scale samples were from steelhead with an Ocean Age of 0, 18 (56.3%) were Ocean Age 1, 9 (28.1%) were Ocean Age 2, and 2 (6.3%) were ocean Age 3 fish. Half-pounder checks were apparent on 14 (43.8%) of the samples examined. Twenty-three (71.9%) of the samples were from maiden spawners, 7 (21.9%) had one spawning check, and 2 (6.3%) had two spawning checks. Circuli counts were made on 29 of the samples from adult steelhead. The mean number of freshwater circuli was 36. Mean circuli counts to the first two freshwater annuli were 12 and 26, respectively, for Age 1+ and Age 2+ fish.

Juvenile Steelhead Studies

During this reporting period, personnel of the Shasta-Trinity National Forest undertook a significant effort to begin habitat typing of streams within the SFTR. The CDFG also entered into an agreement with the Cooperative Fishery Research Unit (CFRU) at Humboldt State University (non-contract [USBR] funds) to support graduate study of streams tributary to the SFTR, specifically Eltapom Creek and upper Hayfork Creek. CFRU personnel employed a variation of the standard habitat typing methodology, with ten habitat types which were condensed into four categories for numerical analysis (Glase and Barnhart 1989).

No clear preference for any habitat type was found for steelhead in Eltapom Creek. Larger juvenile steelhead (51-150 mm) appeared to prefer deep step runs and cascades in Hayfork Creek. However, these two latter habitat subtypes were sampled only once and four times, respectively, so no solid conclusions could be made about juvenile steelhead habitat preferences in Hayfork Creek (Glase and Barnhart 1989).

The present habitat typing methodology is undergoing intensive scrutiny by CDFG personnel to determine if it will be adequate for evaluating existing habitat conditions, and monitoring the impact and quantifying potential benefits of stream channel treatments to improve habitat for both juvenile and adult steelhead. Our intention to assess juvenile steelhead densities and standing crops, via electrofishing and seining of selected tributary streams, and conduct habitat typing was abandoned during this reporting period to avoid duplication of effort. Furthermore, if Shasta-Trinity National Forest personnel continue their high level of effort in habitat typing for the next two or three years, CDFG efforts would be better spent conducting the biological sampling to accompany the habitat typing data collected by others.

During this reporting period, we undertook trapping efforts to collect species and timing data for juvenile salmonids emigrating from the Hayfork Creek basin and the main stem SFTR, above Hayfork Creek. Our trapping results indicated that limited numbers of juvenile steelhead were emigrating during October-December 1988, comprised primarily of Age 1+ and Age 2+ steelhead (Tables 3 and 4). Fifteen steelhead were captured at the main stem SFTR trapping site during 8 nights of trapping, and 4 steelhead were captured at the Hayfork Creek trapping site during 7 nights of trapping. Mean size of steelhead emigrating during the late fall and winter period ranged from 58.5 mm, FL, to 109.0 mm (Table 4).

Due to high flows, emigration monitoring was periodically abandoned in February and March, but began again consistently during April 1989 and continued through June (Table 3). During the spring period, we captured 5,767 juvenile steelhead and 321 chinook salmon at the Hayfork Creek trapping site, and 297 juvenile steelhead and 676 chinook salmon at the SFTR trapping site. Based on a preliminary assessment of our initial scale reading, Age 1+ and Age 2+ steelhead comprised the majority of the catches through April 22 (Julian wk 16) on Hayfork Creek. Age 0+ steelhead dominated the catches thereafter. Peak emigration of Age 0+ steelhead from Hayfork Creek occurred during Julian weeks 21-22 (May 21-June 01) (Table 3). Few Age 0+ steelhead were captured at the SFTR trapping site, most were Age 1+ or older. The peak emigration period for Age 0+ steelhead in the SFTR occurred during the same interval as at Hayfork Creek, Julian weeks 21-22 (May 21-June 01) (Table 3).

Mean FL of juvenile, predominantly Age 0+, steelhead captured at the Hayfork Creek trapping site increased from 31.5 mm in Julian wk 20 (May 14-20) to 47.8 mm by Julian wk 24 (June 11-17) (Table 4).

Hayfork Creek

South Fork Trinity River

Time Intervals			Number			Number
Year	Dates	Julian weeks	Chinook salmon	Coho salmon	Steelhead	Chinook salmon	Coho salmon	Steelhead
1988	Oct.08-21	41-42	0	0	0	0	0	1
	Oct.22- Nov.04	43-44	0	0	1	0	0	2
	Nov.05-18	45-46	0	0	2	0	0	0
	Nov.19- Dec.02	47-48	-	-	-	-	-	-
	Dec.03-16	49-50	0	0	0	0	0	10
	Dec.17-31	51-52	0	0	1	0	0	2
1989	Jan.01-14	01-02	0	0	0	0	0	0
	Jan.15- 28	03-04	0	0	0	0	0	4
	Jan.29- Feb 11	05-06	0	0	0	-	-	-
	Feb.12- 25	07-08	0	0	0	0	0	0
	Feb.26- Mar.11	09-10	0	0	0	-	-	-
	Mar.12- 25	11-12	-	-	-	-	-	-
	Mar.26-Apr.08	13-14	0	0	13	-	-	-
	Apr.09- 22	15-16	0	0	7	0	0	2
	Apr.23-May 06	17-18	58	0	438	0	0	35
	May 07-20	19-20	23	0	527	83	0	34
	May 21- Jun 03	21-22	186	0	3,499	577	0	169
	Jun.04-17	23-24	54	0	1,238	16	0	53
		TOTALS:	321	0	5,747	676	0	312
Dash (-) denotes intervals during which no sampling occurred.

Table 3. Juvenile salmonid trapping summary for the South Fork Trinity River Basin during the 1988-89 season.

Table 4. Size of juvenile steelhead from the South Fork Trinity River Basin, 1988-89 season.

RECOMMENDATIONS

1. The creel census should be continued, as scheduled, through the 1989-90 season, with emphasis on monitoring angler use and steelhead harvest in the lower South Fork Trinity River, early in the season.

2. A system of weirs and traps should be used to estimate the 1990 run size for adult steelhead in the Hayfork basin and in the South Fork Trinity River basin, above Hayfork Creek.

3. The steelhead scale analysis effort should continue as scheduled. Additional scales should be collected from adult and juvenile steelhead within the South Fork Trinity River basin, and all scales, including ones already collected, should be read as quickly as current staffing levels will allow.

4. The juvenile steelhead monitoring effort should be continued, as scheduled, to track the emigration patterns of juvenile steelhead in Hayfork Creek during the April-June period.

5. Efforts at habitat typing, and assessments of juvenile steelhead density and standing crop, should be coordinated with other work being conducted by the staff of the CFRU and Shasta-Trinity National Forest, to eliminate duplication of effort and optimize results.

LITERATURE CITED

Glase J. D. and R. A. Barnhart. 1989. Temporal utilization by naturally produced steelhead juveniles of various habitat types within selected South Fork Trinity River tributaries. Annual Job Performance Report, Sport Fish Restoration Project #F-43-R-1, Study #3, Job #3. Calif. Dept. Fish and Game, Inland Fish. Div., Sacramento, CA. 95814

Kesner, W.D. and R. A. Barnhart. 1972. Characteristics of the fall-run steelhead trout (Salmo gairdneri) of the Klamath River system with emphasis on the half-pounder. Calif. Fish and Game, 58(3): 204-220.

Miller, E.E. 1975. A steelhead spawning survey of the tributaries of the upper Trinity River and upper Hayfork Creek drainages, 1973. Calif. Dept. Fish and Game, Anad. Fish. Admin. Rept. No. 75-5. 8pp.

Ricker, W. E. 1975. Computation and interpretation of biological statistics of fish populations. Fisheries Research Board of Canada, Bulletin #191.

Rogers, D.W. 1972. A steelhead spawning survey of the tributaries of the upper Trinity River and upper Hayfork Creek drainages, 1971. Calif. Dept. Fish and Game, Anad. Fish. Admin. Rept. No. 72-12. 6pp.

Rogers, D.W. 1973. A steelhead spawning survey of the tributaries of the upper Trinity River and upper Hayfork Creek drainages, 1972. Calif. Dept. Fish and Game, Anad. Fish. Admin. Rept. No. 73-5A. 8pp.

APPENDICES

Appendix 1. List of Julian weeks and their calender date equivalents.