Table 2-2.
Adult salmonand steelhead estimates from 1963-1992 with years omitted for which there is
no data available. Estimates from erick Gerstung (unpublished data), Dean (in press),
Wilson and Collins 1992, Carrie Wilson personal communication, Jong and Mills (in press).
Year Spring Fall Coho Salmon Winter Summer
Chinook Chinook* Steelhead Steelhead
1963 10000 ND ND ND ND
1964 11600 3337 ND ND ND
1970 100c ND ND ND ND
1971 98d ND ND ND ND
1972 13d ND ND ND ND
1974 36a ND ND ND ND
1975 322a ND ND ND ND
1976 342a ND ND ND ND
1979 301a ND ND ND ND
1980 25c ND ND ND ND
1982 161a ND ND ND 27
1984 27c ND ND ND ND
1985 300e 2640 127 ND 8
1986 183a 1580 ND ND 73
1987 153b 474 ND ND ND
1988 59a 454 ND ND 26
1989 7b 513 ND ND 37
1990 92b 345 99 ND 66
1991 220a ND ND 2326 ND
1992 330a ND ND 3500 ND
a 90-100% of holding area surveyed
b 70-90% of holding area surveyed
c 40-70% of holding area surveyed
d 20-40% of holding area surveyed
e expansion based on index reach
*Fall Chinook estimates include jacks
Figure 2-1. Returns of South Fork Trinity River fall chinook salmon from 1985-1990 with Age 2 fish (jacks) distinguished from older aged adults. NOT AVAILABLE IN ELECTRONIC FORMAT
Table 2-3. South Fork Trinity River female fall chinook salmon sex ratio, number returning
mortality and number surviving to spawn. Data from Jong and Mills (in press).
Year Sex Ratio: # of % Mortality # of # Female
M to F Females Morts Spawners
1985 78:22 580 71% 412 178
1986 64:36 569 8% 46 523
1987 71:29 137 14% 19 128
1988 82:18 81 0 0 81
1989 56:44 226 12% 27 199
1990 89:11 38 50% 19 19
Extremely Low Numbers of Coho Salmon Return
Almost no information on population trends or abundance are available for coho salmon anywhere in the Klamath/Trinity basin, except for one reference in Snyder (1931), who noted a commercial catch in 1919 of 11,162 between September 20 and October 22. The destination of the coho in these counts was never determined. The CDFG weir at Sandy Bar tagged enough coho salmon and recovered a sufficient number of carcasses to generate estimates for 1985 and 1990 (Table 2-2). Jong and Mills (in press) set escapement in 1985 at 127 coho salmon and at 99 coho in 1990. The 1985 run may have been largely composed of strays, and females had an estimated mortality of 99.6% (Jong and Mills, in press).
In the more recent survey, the counting weir in the South Fork Trinity was operated into March 1991, and the bulk of coho spawning took place in January. This latter run pulse fits general life history patterns expected of native Klamath Basin coho salmon (Leidy and Leidy, 1984). Most weir operation in the South Fork Trinity Basin has usually ended when stream flows increased in November (Jong and Mills, in press), so it is possible that this is a remnant run that has not been well sampled or estimated. Pre-spawn mortality of female coho salmon in 1990 was 36 percent.
Winter Steelhead Not At Risk, But Down From Historic Levels
Local anglers report that the abundance of winter steelhead has declined substantially since the 1964 flood. This observation is consistent with findings of Rogers (1972,1973) who compared redd counts from 1964 and 1972 for upper Trinity River tributaries and Hayfork Creek and its tributaries. In 1964 there were over 5,000 redds counted, in contrast to 352 in 1972. Anglers interviewed recalled a resurgence in abundance of steelhead in the late 1970's but a subsequent drop in the 1980's.
From 1990 to 1992 South Fork Trinity winter steelhead have been counted and tagged throughout the winter to estimate population levels and the rate of angler harvest. Flow conditions in 1990-91 and 1991-92 permitted weir operation throughout much of the winter and runs of winter steelhead were estimated at 2356 and 3500, respectively (Wilson and Collins, 1992; Carrie Wilson personal communication). Fishermen thought that 1991-92 represented a year of fairly high abundance relative to other recent returns. Steelhead redd counts have been conducted in numerous tributaries of the South Fork Trinity basin including tributaries of Hayfork Creek (Table 2-4). Relatively high concentrations of redds were spotted in the East Fork of the South Fork, Plummer Creek, East Fork of Hayfork, upper Salt Creek, Big Creek (Hayfork), and in Eltapom Creek (Mills and Wilson, 1991; Wilson and Mills, 1992; Wilson and Collins 1992).
Standing crops of juvenile winter steelhead have been monitored by the U.S. Forest Service on Hayfork Creek, Big Creek (Hayfork), Salt Creek, Rusch Creek, and Rattlesnake Creek from 1985 to 1990 (Van Deventer, 1992). Almost all streams surveyed showed a decrease in abundance of juvenile steelhead over the five years, but an increase in the weight of individuals has somewhat offset decreases in numbers.
Angler harvest rate of South Fork Trinity River winter steelhead from 1988-89 to 1990-91 was estimated to be 6%, 18%, and 10% based on creel census (Mills and Wilson 1991, Wilson and Mills 1992, Wilson and Collins 1992). Thus, in-river sportfishing may not be limiting the recovery of this population. Indian harvest rate is unknown, but 30% of all fish captured exhibited net scars in 1989-90 (Wilson and Mills 1992) and 6% in 1990-91 (Wilson and Collins 1992). Considering that there is probably negligible ocean harvest of steelhead, fishing is not indicated as a limiting factor for steelhead in the South Fork Trinity basin.
Summer Steelhead: Population Low But Baseline Unknown
Baseline information for summer steelhead populations from before the 1964 flood is lacking, although there are indications that summer steelhead were never abundant in the South Fork Trinity River. LaFaunce (personal communication) found no adult summer steelhead in seine hauls mixed in with the hundreds of spring chinook trapped during tagging operations. Local ecological conditions may have favored spring chinook. While summer steelhead may never have been dominant in the South Fork, loss of holding pools and warm summer water temperatures may have reduced the existing population of this species after the 1964 flood. Recent dive sweeps to count spring chinook have found an annualaverage of 50 summer steelhead individuals spread throughout the entire drainage (Table 2-1).
Dean (personal communication) counted 42 summer steelhead at the counting weir used to tag spring chinook during early summer in 1993. He tagged and captured 62 spring chinook and preliminary estimates are that well over 500 adults were present. It would seem that the summer steelhead return in the South Fork Trinity River basin in 1993 was in the hundreds.
Table 2-4.
Steelhead Counts in South Fork Tributaries 1988-91. (Taken from Mills and Wilson,
1991; Wilson and Mills 1992; Wilson and Collins 1992).
Stream Name 1988-89 1989-90 1990-91
Big Creek 0 36 23
(Hayfork)
Big Creek 1 1 1
(Hyampom)
Butter Creek 4 44 9
Carr Creek 0 0 2
Dubakella Creek NA1 0 0
East Fork Hayfork NA 32 17
Creek
East Fork of South NA 38 52
Fork
Eltapom Creek 2 18 8
Goods Creek NA 0 1
Hayfork Creek NA 30 48
Kerlin Creek 0 NA NA
Little Creek NA NA 3
Olsen Creek NA 2 1
Pelletreau Creek 0 0 2
Philpot Creek NA 6 0
Plummer Creek NA NA 21
Potato Creek NA 5 0
Rattlesnake Creek NA 24 9
Rusch Creek NA 6 13
Salt Creek NA 57 15
Silver Creek NA 4 0
Smokey Creek NA 16 12
1 NA means no count was conducted on the stream in that year.
Chum Salmon
Only incidental numbers of chum salmon are seen every few years at the Sandy Bar weir (Jong and Mills, in press). It could not be verified that chum salmon were once a viable run in the South Fork Trinity River, either from scientific files or personal experience of basin residents.
Pacific Lamprey Poorly Studied But May Be Decreasing
While no formal studies have ever been conducted on lamprey in the Klamath or Trinity River basins, a general decline in the species is recognized by Native Americans who fish for them at the mouth of the Klamath (USFWS, 1991). Residents of the South Fork Trinity River basin also feel the abundance of Pacific lamprey has declined over the years. Summer and fall migrating adults, as well as developing juveniles, would find survival difficult in 80° F waters of the lower South Fork and Hayfork Creek.
Pacific lamprey juvenile spend several years in fresh water (Moyle, 1976). As they grow in size, they may exceed carrying capacity of smaller tributaries and move downstream to colonize other areas. Lack of juvenile survival in the main stem habitats, which have severe thermal problems and unstable sediments, could possibly be a cause for declines in abundance of this species.
In 1990, the California Sportfish Protection Alliance requested that the California Department of Fish and Game take action to list South Fork Trinity River summer steelhead and spring chinook as threatened or endangered under the California Endangered Species Act (Baiocchi, 1990). The Department did not initiate such action but subsequently began studies to discover the status of spring chinook in the South Fork Trinity River. The California Act is patterned after the U.S. Endangered Species Act (ESA) of 1973, as amended in 1978 (16 U.S.C. 1531 et seq), which was initiated to prevent the loss of biological diversity represented by various organisms or sub-populations of species. In order to achieve that objective, the ESA acts as a mechanism "whereby the ecosystems upon which endangered or threatened species depend may be conserved."
How Do Populations Qualify Under the Endangered SpeciesAct?
Isolated breeding populations of salmon or steelhead may qualify under ESA but determining which populations qualify for such protection can be complex (Utter, 1981). In recent years winter run chinook salmon of the Sacramento River and several stocks of Columbia River salmon have been listed as threatened or endangered (NMFS, 1987, 1991, 1991a). If an isolated breeding population is found to be declining and requests are made for its protection, the National Marine Fisheries Service is in charge of determining if the population is of substantial ecological or genetic importance (Waples, in press). NMFS uses the following criteria to make that determination:
* Is the population genetically distinct?
* Does the population occupy unique habitat?
* Does the population show unique adaptations to its environment?
* If the population became extinct, would this event represent a significant loss to the ecological or genetic diversity of the species?
Are South Fork Stocks Candidates For Listing?
A regional report from the American Fisheries Society (Higgins et al., 1992) designated South Fork Trinity River spring chinook and summer steelhead as at "high risk of extinction" while coho salmon and fall chinook salmon were listed as "stocks of concern" due to low and unstable returns. The decline of populations is a strong component of listing under ESA (Bjornn and Horner, 1980) and the drop of spring chinook from 11,600 to a few hundred, or less, certainly meets this criteria. Recent escapement trends for fall chinook (Jong and Mills, in press) also indicate a substantial decline from the 1964 population level of 3,337, with native spawners numbering fewer than 500 in some years (Table 2-1). With populations such as summer steelhead and coho salmon, there is a less well documented decline. However, it is clear that if a major storm event occurred, and resulted in widespread sediment production throughout the South Fork, it could contribute to the effective extinction of several of these stocks.
Distinctive Genetic Traits: Studies on genetic structure of steelhead in the South Fork Trinity River showed that there were significant differences between native fish and those from the Trinity River Hatchery (Baker, 1988; Hodges et al., 1989). It was assumed that winter steelhead constituted the bulk of the samples taken in these tests, but genotypes of summer run and winter run fish from the same basin are often indistinguishable (McIntyre, 1984). Gall et al. (1990) studied chinook salmon genetic material from a number of locations within the Klamath basin using starch-gel electrophoresis. He included one sample from the South Fork Trinity River. The tests found little significant difference between most populations sampled, with the exception of lower Klamath fall chinook salmon which had a genetic identity more similar to Smith River and southern Oregon stocks (Gall et al. 1990). Utter et al. (1992) cautioned against drawing conclusions from starch gel electrophoresis tests using only a restricted number of places (loci) on the genome. More refined analysis of fall chinook gene resources in the basin are currently in progress (Chuck Lane personal communication). No genetic tests have been conducted on South Fork Trinity coho salmon.
Questions regarding gene resources are automatically raised by the high incidence of straying found in fall chinook salmon and coho salmon. One major introduction of spring chinook juveniles from Trinity River Hatchery in 1973 also may have altered the genetic make up of the South Fork stock. Genetic changes may not occur, however, if there was no gene flow into the population (Riggs, 1990). This could result from extremely low survival of introduced juveniles or low survival of the progeny of hatchery adults returning to the South Fork Trinity River. Whether or not a population is genetically distinct may not ultimately be the best test of its uniqueness or value (Utter, 1981). Genetic changes occur in a population at a relatively fixed rate of one per 10,000 years (Wilson and Sarich, 1966). If populations in the South Fork Trinity River have only recently split off from those of the main Trinity River or other sub-basins, they may have very few genetic differences from one another. Our understanding of the link between behavior and genetic structure is incomplete, but it has been documented that fish with very similar genetic structure can display dramatically different behavioral traits (McIntyre, 1984). Consequently, even if South Fork Trinity River stocks are not unique genetically, they may have evolved behavioral traits that are essential to survival in the basin and that make them irreplaceable.
Unique Habitat: Since the majority of South Fork Trinity River tributaries have small drainage areas and steep gradients, most historical salmon spawning probably took place in the main South Fork Trinity River, in Hayfork Creek, or in a few other large tributaries. Poor access to many tributary streams may have naturally limited summer steelhead production in the basin. Long time local residents noted that, earlier in the century, the snow did not melt on South Fork Mountain until July and that ice jams sometimes helped scour the deep holes that harbored spring chinook during summer (Albert Bramlet personal communication). Cold winter stream temperatures and abundant snow melt runoff during the summer may have combined to confer a selective advantage to the spring chinook salmon in the basin, compared to the fall chinook life history type. This hypothesis would be consistent with higher spring chinook population in the only pre-1964 count taken in the basin (LaFaunce 1967).
Unique Adaptations: The question of whether or not South Fork Trinity River salmon and steelhead stocks have unique adaptations is also one that has not been answered. Continuing studies in the basin may help to discern such traits. Dean (in press) has noted that South Fork Trinity adult spring chinook salmon can migrate between holding pools in summer even when the stream temperature is over 75°F. This temperature is generally thought to be lethal to salmon and steelhead (Reiser and Bjornn 1979); therefore, high temperature tolerance could be construed to be an important adaptation of South Fork spring chinook.
White (1974) found that juvenile spring chinook from the Trinity River Hatchery, which were transplanted into the South Fork Trinity River in 1972, seemed to have moved downstream in response to increasing water temperatures. Moffett and Smith (1950) noted that temperatures in the main Trinity River prior to dam construction were 74°F during summer. Thus, avoidance of warm stream temperatures during summer may be one of the traits that both main stem and South Fork chinook juveniles hold in common. However, a significant number of South Fork Trinity River spring chinook juveniles spend a full year in freshwater (Dean, in press), a rare trait in the Klamath basin (Sullivan 1989).
Evolutionary Significance: The extinction of South Fork Trinity River stocks might not represent a significant loss to the ecological or genetic diversity of the species, but if it does and these fish are lost, recolonization of the South Fork Trinity River with fish from other areas may not be possible. The fact that salmonid stocks in the basin have persisted despite extreme environmental adversity suggests that they offer the best prospect for restoration and that they may possess important gene resources. For this reason, it would seem prudent to make every effort not to lose any South Fork River salmon or steelhead stocks.
The Pros and Cons of Using ESA to Protect South Fork Stocks
Use of the ESA to protect populations of any plant or animal faced with extinction can be a powerful tool, but it may not be the best mechanism to save South Fork Trinity River salmon and steelhead stocks. The primary advantage offered by ESA is that it compels Federal agencies to take every step necessary to prevent loss of habitat and to prevent harm of listed species. Since the U.S. Forest Service is showing increased willingness to take all necessary steps to prevent extinction of endangered salmon and steelhead (USFS, 1992), use of the ESA to win cooperation of this agency may not be necessary. The ESA has less control over habitat loss or damage to threatened or endangered species on private land. The affect of listing salmon or steelhead stocks of the South Fork Trinity River on activities on private land is difficult to predict.
Ironically, listing engenders such a cumbersome bureaucratic process that any action, even those to promote species recovery, can be difficult. The U.S. Fish and Wildlife Service reduced the status of Paiute cutthroat trout from endangered to threatened so that recovery efforts could be less constrained (Eric Gerstung, personal communication). Likewise, the protected status of the northern spotted owl in now creating regulatory hurdles for fisheries habitat improvement projects in the South Fork Trinity basin (Gary Flosi, personal communication).
Fuller (1993) suggests the Pacific Fisheries Management Council (PFMC) has failed to recognize the need to protect depressed stock groups within the Klamath basin, such as South Fork Trinity River chinook salmon (see Chapter VII). This lack of recognition could inhibit recovery and even contribute to the extinction of South Fork stocks. The PFMC accords special status in its management to any stock listed under the ESA, so listing could help decrease ocean harvest of South Fork stocks. Recognition of a species as threatened or endangered also may trigger increases in funds available to help restore the species or its habitat.
Ultimately, the restoration of salmon and steelhead in the South Fork Trinity River basin relies on cooperation within the community. The most potentially dangerous side effect of listing South Fork Trinity River stocks under the ESA might be the alienation of local community members. They have already been disappointed in the activity surrounding the listing of the northern spotted owl. There is a positive feeling among community members about restoring fisheries which might be diminished or lost if listing occurs. Listing under the ESA involves new agencies from outside the area who can mandate changes in local land and water use practices. Solutions to the problems facing salmon and steelhead of the South Fork Trinity River could probably be determined and implemented more readily if basin residents and land managers provide their support and cooperation for implementing the necessary changes.