Fall chinook run strengths have been well studied
since 1978 in the Klamath Basin (See addendum at the end of this chapter,
provided by the California Department of Fish and Game, 1990). The escapement
of adult fall chinook to the Klamath River drainage showed a sharp increase
in 1986 and returns remained high in 1987 and 1988 (Figure
4-1). Graphs of population trends in this report follow the convention
of the Klamath River Management Council (KFMC) and Pacific Fisheries Management
Council (PFMC), which omits grilse salmon from spawning escapement estimates.
Returns in 1989 dropped off and estimates for 1990 indicate extreme lows
in both catch and escapement. Trends in
self-reproducing wild populations have been obscured by the lack of
separation of these fish from hatchery strays (USFWS 1988a), but data suggests
that much of the resurgence in the fall chinook salmon population is owing
to increased hatchery returns.
Many fall chinook salmon stray from the Iron Gate Hatchery on the upper Klamath River into Bogus Creek, which is immediately adjacent (Randy Baxter personal communication). Despite this straying, Bogus Creek returns have made up a strong component of what has been considered "natural" escapement in the Klamath Basin (Figure 4-2). Shasta River returns (Figure 4-3) show no increase since fishing pressure in the ocean was reduced in 1985. Escapement levels on the Shasta remain just a third of Basin population levels of the 1970's (USFWS 1979). The Scott River has failed to show improved returns since the reductions in harvest (Figure 4-4). The Salmon River is one of the only monitored populations not influenced by hatchery returns to show an upward trend (Figure 4-5). This increase suggests that harvest reductions are allowing some recovery where habitat is not limiting (USFWS 1988a).
On the Trinity River, fall chinook runs are becoming increasingly hatchery dominated. The ratio of hatchery to wild fall chinook on the Trinity was estimated in 1987 to be nearly 90-to-10 (USFWS 1988a). While returns have been high in the main stem of the Trinity below the hatchery, Stempel (1988) estimated that greater than 60 percent of the fish spawning in this area were first-generation hatchery fish. Levels of escapement on the South Fork, the native wild population monitored by a weir on the Trinity, have been declining and estimated escapements for 1987 and 1988 were about 400 adults (CDFG unpublished). LaFaunce (1965) estimated that 3,600 fall chinook returned to the South Fork of the Trinity in 1964.
Data from which to determine the number of fall run chinook returning to the lower Klamath tributaries is, for the most part, unavailable. The 1988 escapement in Blue Creek was estimated to be 320 (USFWS 1990c). DeWitt (cited by USFWS 1979) estimated fall chinook escapement in Blue Creek in 1951 at between 5,000 and 10,000 fish. USFWS outmigrant traps catch very few chinook smolts in the smaller tributaries below Weitchpec, suggesting their low abundance (USFWS 1990).
Spawner surveys by the U.S. Forest Service on the middle Klamath tributaries, such as Red Cap and Camp creeks, suggest that escapement of the native late run fall chinook stocks are quite low (J. Boberg personal communication). Similar low redd and carcass counts have been found on Hoopa Valley Reservation tributaries and suggest low population levels of late run fall chinook (Hoopa Fisheries Reports 1984-88).
Runs of Trinity River hatchery-origin spring chinook showed a strong increase from 1985-1988 (Figure 4-6). While 1987 and 1988 were the highest returns in recent years, 1989 showed a decrease from the trend and 1990 showed further declines. USFWS (1990b) has found a strong relationship between pounds of juvenile spring chinook released at Trinity River Hatchery and subsequent returns and projected lower escapement levels for 1990.
The native spring chinook on the South Fork of the Trinity River appear not to have recovered and, in fact, may be trending toward extinction. While 11,500 spring chinook spawned in the South Fork in 1964 (LaFaunce 1965), less than 50 spring chinook were sighted during extensive direct observation surveys in the summer of 1989 (USFS unpublished). The 1964 run size estimate may have been higher than average for the years of that period (Eric Gerstung personal communication).
California Department of Fish and Game and Klamath
National Forest personnel have cooperated in assessing spring chinook runs
in the Salmon River since 1980 (Figure
4-7). Data differ in their levels of confidence for the different years.
In some years fairly complete counts by direct observation have been conducted,
while in other index sections are checked and the counts expanded in order
to estimate run size. Run strength seemed to be showing an increasing trend,
peaking in 1988 at 1,500 adults, but runs in 1989 and 1990 were estimated
at only 129 and 113, respectively (DesLaurier and West 1990). Klamath Basin
native spring chinook stocks were described by an American Fisheries Society
report as being at a "high risk of extinction" (Nehlsen et al. 1990). Returns
to other tributaries such as Clear, Elk, and Indian Creeks are estimated
to be as low as ten fish.
Coho were once abundant in the lower Klamath tributaries (Snyder 1931). The exact status of wild coho populations in the lower river today is not known. U.S. Fish and Wildlife Service outmigrant studies (1990a) indicate that very few juvenile coho are present in the smaller lower Klamath tributaries. Low numbers of juvenile coho have also been found in Blue Creek (USFWS 1990c).
No accurate assessment of coho is available for other areas of the Klamath Basin. Although coho are seen at the counting weirs operated on the Salmon, Scott, and Shasta rivers, these weir counts are not be good indicators of coho population levels. The weirs are operated primarily to count fall chinook and they are shut down before the native coho migrations would peak. Severe summer water quality problems may have eliminated the coho salmon stock groups adapted to the Shasta and Scott rivers, since juvenile coho usually spend a full year in their natal stream.
Coho salmon returns to Iron Gate Hatchery since 1970 have ranged from 91 to 2,893 fish, with an average of 1,300 (Hiser 1989). Trinity River Hatchery returns of coho since 1970 averaged 4,000, while ranging from 47 to 23,338 (Bedell 1989). Returns to the Trinity River Hatchery have been very strong in recent years, particularly 1985, 1987, and 1988.
The populations of native steelhead that return to the Klamath River Basin in fall seem to be declining. Seining operations conducted by the California Department Fish and Game at Waukel Riffle showed a decreasing trend in half pounder to adult ratios between 1976 to 1982 from 67:33 to 50:50 (Hubbell 1979, Hubbell et al. 1985). Half pounder run sizes, as estimated by average number caught per seine haul, dropped by 75 percent between 1980 and 1982 (Hubbell et al. 1985). Over the same period the contribution of hatchery fish to the steelhead seine catch grew from 4 percent in 1977 (Hubbell 1979) to 12 percent in 1982 (Hubbell et al. 1985).
This combination of increasing hatchery contributions to catch, together with decreases in steelhead abundance was taken to represent "reductions in naturally produced fall steelhead" (Hubbell et al. 1985). The same report found that Iron Gate Hatchery steelhead did not survive well to adulthood. Reports from the CDFG seining operation since 1982 did not note the number of half-pounders bearing hatchery fin clips (Hopelain unpublished). Steelhead marking was discontinued at Iron Gate and Trinity River hatcheries in 1982. Consequently, trends in the contribution of hatchery and wild fall steelhead since 1982 are not documented.
The California Department of Fish and Game conducted creel censuses that measured catch per unit of effort from 1980 to 1982 (Lee unpublished) and from 1984 to 1987 (Hopelain unpublished). These data indicate that the catch per unit of effort of half-pounders dropped continuously during the period (Figure 4-8). The half-pounder catch rate of 0.081 fish per angler hour recorded by Lee (unpublished) in 1980 had dropped to 0.020 by 1987 (Hopelain unpublished). Adult steelhead catch rates decreased from 0.042 fish per angler hour to a low of 0.017 in 1987.
The continuing decline in catch per unit of effort would indicate that the decreasing trend in native steelhead production is continuing. Hopelain (unpublished) suggests that this may not be the case, but he offers no alternative hypothesis. (The possibility that reduced escapement of wild steelhead is related to interaction with hatchery fish is explored in Chapter 5). Hatchery steelhead are reared for a full year before their release, so they are sheltered from stream conditions. A decrease in suitable habitat for 1+ native steelhead could also be a cause for their relative decline (CDFG 1990).
Returns of adult steelhead to the Trinity River in fall and winter have been strong in some recent years. These increases coincide with increased returns to the Trinity River Hatchery. (For hatchery returns see Chapter 5). While there is a significant sport fishery for winter steelhead in years when streamflows permit, no indications of run strength or population trends are available for these fish. The U.S. Fish and Wildlife Service will be operating a weir during fall and winter months on the New River to attempt to get more information on fall and winter steelhead (Sandy Noble personal communication). This effort is being funded by the Trinity River Fish and Wildlife Management Program.
The U.S. Fish and Wildlife Service (1983) characterized the Klamath Basin's summer steelhead as a "depleted stock of natural origin, possibly approaching threatened or endangered status." USFS and CDFG personnel have made partial counts of summer steelhead over the last several years (Table 4-2). Estimates are based on expansions of the counts from stream segments in most cases, and vary in their levels of precision. Returns were high in 1988 but dropped again in 1989 (Eric Gerstung personal communication). No clear trend for summer steelhead populations basinwide are apparent. DesLaurier and West (1990) expressed concern about population levels of summer steelhead on the Salmon River.
Some populations of summer steelhead, such as those in the North Fork of the Trinity River, the New River, and Clear Creek have remained at stable levels, and at levels sufficient to avoid genetic risk. Clear Creek may see increased sedimentation as a result of salvage logging, which Roelofs (1983) suggested can cause population declines of these fish.
Green sturgeon are listed as rare and endangered in the USSR (Borodin et al. 1984) and rare in Canada (Houston 1988). While the Klamath population may represent one of the world's larger populations, little information on run strengths and population trends exist (Pat Foley personal communication). The only data collected on green sturgeon is the number taken annually in Indian gill nets since 1980. USFWS (1988a) reported 232 captured in 1988 and 191 in 1987. Both the 1987 and 1988 harvests were well below the 500 fish average taken over the monitoring period. The highest catch reported was that of 1981, when 835 green sturgeon were harvested.
Because green sturgeon do not reach maturity until an average age of 15 for males and 20 years for females, fish returning to spawn in 1981 would have been one of the last from brood years prior to 1964. Reduced harvest may reflect a decreasing trend in the green sturgeon population due to habitat problems following the 1964 flood. The construction of Trinity Dam and the subsequent diversion of more than 80 percent of the Trinity's flow may also have had a negative impact. Studies from the Columbia River have linked decreased flows to decreased white sturgeon populations (Craig Tuss personal communication).
Coastal Cutthroat Trout
Indian fishermen have noticed a dramatic decrease in candlefish populations in recent years (Merke Oliver, personal communication).
Some chinook salmon and steelhead stock groups in the Klamath basin have reached very low levels. Fisheries scientists have offered different suggestions as to what minimum number of fish is needed to maintain sufficient genetic diversity in a population so that it will not be lost. Suggestions of critical levels have ranged from a minimum of 500 fish to as few as 50 pair of spawners (Riggs 1990). These considerations in the past usually involved founding hatchery populations from existing stocks. More recently, however, they have been calculated to determine minimum viable populations to avoid species becoming extinct (Gilpin and Soule 1986). Utter (1981), in a study for the National Marine Fisheries Service, concluded that reproductively isolated populations of salmon and steelhead should be considered species, as that term is used in the Endangered Species Act of 1973 (ESA).
Immediate action is needed to avoid the loss of some Klamath Basin stock groups and the genetic diversity they possess. Table 4-4 shows which stock groups have been reduced to low levels, the reasons suspected for their decline, and the methods to be used to rebuild these "priority stocks for recovery." Petitions to list stock groups on the Columbia River under the ESA are currently under evaluation by the NMFS. A major objective of the Restoration Program is to obviate the need for the application of the ESA to Klamath River stocks. All management activities including habitat, harvest and hatchery production affect preservation of genetic resources (NWPPC 1990).
The low number of anadromous fish currently returning to the Klamath River is essentially the result of habitat degradation. Serious problems exist in many tributaries throughout the Basin. Taken together they contribute to large-scale ecological problems in the main river and the estuary. Although the effects of logging on fish habitat and the problems related to water quality and diversion are discussed in Chapters 2 and 3 of this Plan (Habitat Protection and Habitat Restoration, respectively), specific problems need to be reference in this section, as well.
Table 4-3 lists the habitat problems which frustrate the recovery of fish populations in the Basin. Most of the stock groups listed are known to be at very low levels, and some are in need of immediate habitat improvement to avoid their loss. Further habitat decline, linked to a major flood, is possible and could threaten some of the anadromous fish populations listed with extirpation.
The potential impacts of harvest and hatchery practices on priority stocks for recovery must also be determined and remedial actions pursued quickly. If populations that have only recently become depressed, such as the spring chinook on the Salmon River, are rebuilt quickly, then prospects for minimizing genetic loss and for effective recovery are greatly improved (Riggs 1990).
At the same time that the Klamath River Basin Act created the Task Force to guide the restoration of the river's fish habitat, it also created the Klamath Fishery Management Council (KFMC) to guide the allocation of the available fish between the user groups in ways that would allow the rebuilding of the river's fish populations. The KFMC makes allocation recommendations to the Pacific Fishery Management Council (PFMC), which makes the annual harvest quota regulations. While no formal mechanisms have yet been developed to coordinate the work of the two statutory Klamath Basin bodies, they have some overlap in their memberships and even more overlap in the technical advisory groups that serve them. Consequently, informal coordination between the Task Force and Council occurs at a fairly effective rate. (See Chapter 7). The Trinity River Task Force senses similar needs for coordination, but its attempts to seek "advice and leadership of harvest managers on data needs" have reportedly met with "no formal response" (USFWS in press). The KFMC is drafting its own long range plan and will be seeking public comment on it in early 1991 (KFMC 1991).
The 11-member KFMC includes representatives of commercial fishermen, anglers, the Basin's Indian Tribes, the California Department of Fish and Game, Oregon Department of Fish and Wildlife, and the U.S. Secretaries of Commerce and Interior. By joining the user groups and agency personnel together, attempts are made "to minimize conflict, allocate the harvest to optimize commercial, recreational, and aesthetic benefits to the public, and to establish a process for decision-making that is logical, open, and well understood by the public (KFMC 1991)."
The KFMC is served by a Klamath River Technical Advisory Team (KRTAT) which studies the chinook salmon populations in an attempt to predict their run sizes. They computer-model the abundance of salmon cohort year-groups through time to determine the abundance of the different year classes, and, thereby to estimate their return to the river (KRTAT 1989). Harvest rate objectives are set at 65 percent to allow sufficient natural escapement to achieve maximum sustainable yield (MSY). The harvest model uses coded wire tagged hatchery fish to estimate populations and ocean distributions of Klamath Basin salmon stocks. Because the model indicates that the majority of Klamath Basin chinook salmon feed in the ocean between Port Orford, Oregon, and Shelter Cove, California, commercial harvest in this area has been tightly regulated. Some closures to protect Klamath stocks have extended as far south as Point Arena, California and as far north as Coos Bay, Oregon. The Fish and Wildlife Service (USFWS 1988a) suggested that harvest restrictions have helped to increase the escapement of Klamath Basin fall chinook salmon stocks.
