CHAPTER 3. LIFE HISTORY, DISTRIBUTION, RUN SIZE AND ANGLER HARVEST OF STEELHEAD IN THE SOUTH FORK TRINITY RIVER BASIN (Continued)
We surveyed four tributaries to the SFTR in the upper SFTR basin area between 4 and 10 April 1990. These surveys covered a total of 18.8 km, and we observed 82 redds and four live fish (Table 6).
The East Fork of the SFTR (beginning at river km 118) is located in the Yolla Bolla region south of Highway 36. The upper 3.2-km section flows through a rugged, steep-sided canyon and is comprised mostly of riffles and runs, while the lower section levels out into a low gradient stream configuration and is comprised predominantly of cascades and large, deep pools. Spawning gravels were found throughout the surveyed section. We surveyed 4.8 km of the East Fork on 5 April 1990, counted 38 redds, and observed two live steelhead.
Rattlesnake Creek, a tributary to the SFTR (river km 91.7), is located in the Forest Glen area. The upper and middle sections contain spawning habitat, but the lower section is comprised of mainly cascades and very large pools. We surveyed 9.2 km of the creek on 4 April 1990, counted 24 redds, and observed one adult steelhead.
Silver Creek, a tributary to the SFTR (river km 102.7), is located south of Forest Glen in a very steep-sloped mountainous region. Spawning habitat is not abundant, but juvenile steelhead habitat is good throughout the survey reach. High gradient cascades are prevalent in the lower section. We surveyed 2.4 km of the creek on 9 April 1990 and observed four steelhead redds.
Smokey Creek, a tributary to the SFTR (river km 104.1), is located south of Forest Glen. Smokey Creek is characterized as a wide floodplain with abundant spawning habitat and large pools. We surveyed 2.4 km of the creek on 10 April 1990, and observed 16 redds and one adult steelhead.
Project personnel operated three traps and one Alaskan weir during the season to recover post-spawning, emigrant adult steelhead. The traps were operated on Big Creek, Salt Creek and Tule Creek for 94 d from 31 January through 4 May 1990 (Figure 1). The Alaskan weir with a downstream trap was operated for 90 d, from 24 February through 27 May 1990, on Hayfork Creek, 9.6 river km from its confluence with the SFTR (Figure 1).
We captured 12 steelhead (three in Big Creek, nine in Salt Creek) during operation of the three smaller traps. We trapped 91 adult steelhead at the lower Hayfork Creek Weir (Figure 6), including seven steelhead previously trapped in Big Creek and Salt Creek. The remaining 84 steelhead were unmarked. The average size of steelhead trapped at the Hayfork Creek Weir was 62.7 cm FL (Figure 7). Of the 96 fish trapped at the three emigrant traps and the weir within the Hayfork Creek drainage, 37 were male and 59 were female. Mean FL for males was 65.1 cm, (range: 53-79 cm), and 61.2 cm for females (range: 47-78). We did not recapture any of the Project-tagged or fin-clipped steelhead marked at the Sandy Bar and Hyampom Valley Weirs, earlier in the season.
Project personnel also used sport fishing rods and reels to recover nine unmarked adult steelhead in the middle Hayfork Creek drainage and the SFTR in the Hyampom Valley.
Of the 135 steelhead tagged or fin-clipped at the Sandy Bar and Hyampom Valley weirs between 14 September 1989 and 6 January 1990, only seven marked steelhead were recovered (five tagged and two 1/2-LV fin-clipped). Three marked fish from Sandy Bar Weir were observed and re-released at the Hyampom Valley Weir. Four other marked fish (three tagged and one 1/2-LV fin-clipped) were recovered through the creel census surveys, with the last recovery being made on 10 December 1989. We recovered 127 unmarked steelhead through the following methods: 9 by hook-and-line fishing, 6 by electrofishing, 12 through emigrant trapping in tributaries to Hayfork Creek, 84 at the Hayfork Creek Weir, and 16 through the creel census surveys.
A valid Petersen estimate of escapement is based upon certain assumptions being met, including random mixing of both marked and unmarked fish, and random and unbiased sampling for mark recoveries (Ricker 1975). Unfortunately, despite our intensive mark and recovery efforts, we do not feel we can make a valid 1989-90 SFTR basin adult steelhead escapement estimate, primarily because of low recoveries of marked fish and weather-induced alterations in our sampling design.
Since tagging was not possible at the Sandy Bar Weir after October 23, 1989 or at the Hyampom Valley Weir after 6 January 1990, we feel we may have missed the opportunity to mark a considerable portion of the run. Subsequent studies showed SFTR steelhead continued immigrating into the basin throughout the spring. For example, very few redds were seen until mid-March. Additional immigration of fish into the basin may have affected our ability to randomly distribute marked fish throughout all segments of the steelhead run. We feel the steelhead marked at the two weirs in the lower SFTR basin probably constituted the early portion of the winter run, while much of our recovery effort probably targeted later elements of the run. Thus, our marking and many of our recovery efforts may have been widely separated in time.
Our last steelhead was tagged 4 January, prior to the destruction of the Hyampom Valley Weir on 7 January 1990 by a heavy storm. In spite of a variety of intensive recovery efforts throughout the rest of the season, all marked fish were recovered in the creel census during December 1989. Electrofishing was intended as our primary recovery method, and began on 19 December 1989 continuing intensively for the next three months. However, it proved to be very ineffective because few fish were ever seen or captured during the process. In retrospect, the electrofishing method had a low probability of success when we first attempted it, due to high flows and physical inaccessibility to many tributaries. Our traps and weirs for emigrant adult steelhead in the Hayfork Creek basin were operated between 29 January to 6 May 1990 (JWs 5-18), but captured only a few untagged fish. Weather conditions also prevented us from conducting our various recapture efforts on a continuous basis during equivalent (simultaneous/overlapping) time periods. This would have been necessary if we were to use combined totals of all fish recovered by the various techniques in one Petersen estimate of escapement.
Fish may have used the upper SFTR drainage more heavily than expected, while recovery efforts were disproportionately centered in the Hayfork Creek drainage due to access problems within the upper SFTR.
Marked fish may have had higher mortality (natural or fishing) or emigrated out of the SFTR basin prior to the bulk of our recovery efforts, which would also account for low recoveries. Only the creel survey recovered any marked fish, and we would have expected to see more fish with only a 1/2-LV fin clip, since we marked more fish in this manner than with the double mark of an anchor tag and 1/2-LV fin clip.
The only escapement estimates that we can make, therefore, are for the early portion of the steelhead run. We estimate that 969 adult steelhead (95% Poisson C.I.: 396 to 2,422) migrated past Sandy Bar Weir through 23 October 1989, based on recoveries at the Hyampom Valley Weir, which was 38.6 km upstream from the tagging site. This is similar to our second estimate that 571 adult steelhead (95% Poisson C.I.: 255 to 1,428) migrated past Sandy Bar and Hyampom Valley Weirs through 6 January 1990, based on recoveries in the creel census. This second estimate is less reliable, since it is based on tagging at two different weirs, both of which cannot necessarily be assumed to have had equal capture efficiencies, and thus to have marked equal proportions of the steelhead run past each weir.
From 1 July 1989 through 30 June 1990, we captured 2,386 Age 0+, 225 Age 1+, and 28 Age 2+ steelhead and 2,172 juvenile chinook salmon at the Hayfork Creek and SFTR juvenile out-migrant trapping sites (Figure 1, Table 8). The peak emigration of Age 0+ steelhead and Age 0+ chinook salmon occurred during May 1990, and the peak emigration of Age 1+ steelhead occurred during April 1990. Age 0+ steelhead were more abundant in Hayfork Creek and chinook salmon were slightly more abundant in the SFTR (Table 8). The mean FL of Age 0+ steelhead from the 1989 Brood Year (BY) increased from 55.4 mm to 96.0 mm by early December 1989, and mean FL of Age 0+ steelhead from the 1990 BY increased from 28.3 mm to 55.9 mm by June 1990 (Table 9). Mean FL's of Age 1+ steelhead ranged from 89.0 to 153.3 mm, and Age 2+ steelhead ranged from 163.0 to 190.0 mm (Table 9). Mean FL's of chinook salmon from the 1989 BY ranged from 52.0 to 83.8 mm (Table 9).
We evaluated juvenile steelhead utilization of the various habitat types in Eltapom Creek from 20 through 28 September 1989. We sampled 52 (50%) of the 103 habitat units identified by Glase and Barnhart (1989) [3 cascades, 17 pools, 12 riffles, and 20 runs], capturing 1,079 juvenile steelhead. Runs were the predominant habitat type within the creek (47% of total area), but fish density was highest in riffles, and secondarily in pools (Table 10).
To date, we have examined 105 adult steelhead scale samples. The majority of
these fish had spent 2 years in fresh water prior to smolting, the rest smolted
at Age 3 (Figure 8). Most spent only one year in the ocean (Ocean Age 1) (Figure
9). Half-pounder checks were apparent on 41 (39%) of the samples examined. Most
scale samples were from maiden spawners (Figure 10). We made circuli counts
on 104 of the adult steelhead scale samples and the mean number of freshwater
circuli was 35. Mean circuli counts to the first and second freshwater annulus
were 12 and 25, respectively, for Age 1+ and Age 2+ fish. Juvenile steelhead scale analysis was conducted using the OPRS machine. We concentrated, primarily, on scale samples of juvenile Age 1+ fish to help clarify the location of the first annulus in adult scales, and have read scales from Age 0+ through Age 2+ fish to further describe juvenile steelhead life history. To date, we have read 464 sets of juvenile steelhead scales, most of which were Age 0+ fish (Table 11). Mean circuli counts to the first and second freshwater annulus for juvenile steelhead scales were greater than the equivalent counts on adult scales (19 and 35 vs. 12 and 25, respectively). Currently, we have no explanation for these observed differences but are evaluating several alternatives.
1. The operation of the Hyampom Valley Weir to capture adult steelhead should be discontinued due to high bed-load movement during storm events. All adult steelhead tagging should be carried out at the Sandy Bar Weir.
2. While the creel survey showed low angler harvest of the SFTR basin steelhead stocks during Fiscal Year (FY) 1989-90, the creel survey should continue during FY 1990-91 to document angler harvest and as a means of adult steelhead tag recovery.
3. Adult steelhead spawner surveys should begin by 1 March on streams tributary to the South Fork Trinity River and Hayfork Creek, weather permitting.
4. Electrofishing to recover adult steelhead was found to be labor intensive and unproductive. Electrofishing efforts should be discontinued.
5. The operation of the Alaskan weir and traps in the Hayfork Creek drainage to capture emigrant, post-spawning adult steelhead was effective and should continue. Next year, a similar weir should be installed in the upper SFTR drainage above Hayfork Creek, if a suitable site can be located.
6. Juvenile out-migrant steelhead traps need to be thoroughly evaluated by marking and releasing groups of Age 0+ and 1+ steelhead and chinook salmon above the trapping sites, and using mark recovery data to assess trapping success.
7. Juvenile steelhead habitat utilization studies should continue next year, with studies conducted both in the spring as well as the fall to compare seasonal habitat use.
8. Steelhead life history studies through scale analysis should continue next year with continued emphasis on the juvenile freshwater phase of the scale using the OPRS.
9. We should determine whether tagging weirs are our only means of assessing steelhead run-size and run-timing. Unpredictable weather and high river flows make weir operations in the winter impossible during most normal water years. Since our weirs cannot be operated under high flow conditions, we may not be able to monitor the entire run.
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. 24 p. Available from Calif. Dept. of Fish and Game, Inland Fisheries Div.-Room 1251, 1416 9th St., Sacramento, CA. 95814.
Hankin, D. G. 1986. Sampling designs for estimating the total number of fish in small streams. Res. Paper PNW-360. U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, OR. 33 p.
Hopelain, J. S. 1987. Age, growth, and life history of Klamath River basin steelhead (Salmo gairdneri), as determined from scale analysis. 33 p. (Mimeo). Available from Calif. Dept. of Fish and Game, Inland Fisheries Div.-Room 1251, 1416 9th St., Sacramento, CA. 95814.
Kesner, W. D. and R. A. Barnhart. 1972. Characteristics of the fall-run steelhead (Salmo gairdneri 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. of Fish and Game, Anad. Fish. Admin. Rep. No. 75-5. 8 p.
Mills, T. J. and C. E. Wilson. 1991. Life history, distribution, run size, and angler harvest of steelhead in the South Fork Trinity River basin. Chapter III. Job III. p. 34-51. In: Carpenter, R. and K. Urquhart (eds.), Annual report. Trinity River basin salmon and steelhead monitoring project, 1988-1989 season. 51 p. Available from Calif. Dept. of Fish and Game, Inland Fish. Div.-Room 1251, 1416 9th St., Sacramento, CA. 95814.
Price, D. G. 1982. A fishery resource sampling methodology for small streams. Pacific Gas and Electric Company, Department of Engineering Research, Rep. 420-81.141. 49 p.
Ricker, W. E. 1975. Computation and interpretation of biological statistics of fish populations. Bull. Fish. Res. Board Can. #191. 382 p.
Rogers, D. W. 1972. A steelhead spawning survey of the tributaries of the upper Trinity River and upper Hayfork Creek drainages, 1971. Calif. Dept. of Fish and Game, Anad. Fish. Admin. Rep. No. 72-12. 6 p.
Rogers, D. W. 1973. A steelhead spawning survey of the tributaries of the upper Trinity River and upper Hayfork Creek drainages, 1971. Calif. Dept. of Fish and Game, Anad. Fish. Admin. Rep. No. 73-5A. 8 p.
