Hypothesis #1: The distribution and abundance of coho salmon and steelhead in the Gualala River basin have diminished in recent decades.
Support for the Hypothesis
Taylor (1978) estimated the annual adult return of coho salmon as 4,000 and the steelhead population at 16,000 in the early 1960's (table). Although the California Department of Fish and Game did not conduct coho salmon population surveys in the Gualala River, Bruer (1953) asserted that there were millions of steelhead and coho salmon juveniles. The summer "trout" fishing for juvenile steelhead smolts was quite productive in tributaries, including the mainstem Wheatfield Fork (Spacek, 1997). Fox (1964) surveyed extensive reaches of the Wheatfield Fork and found 200 steelhead per hundred feet of stream, with steelhead comprising 80% of the fish community and Gualala roach only 20%. Kimsey (1953) sampled the lower mainstem Gualala River using electrofishing in 1952 and found the reach dominated by steelhead juveniles, with some roach, stickleback and sculpin present. California Department of Fish and Game historic surveys noted that coho salmon inhabited the North Fork Buckeye Creek, Fuller Creek, Haupt Creek, North Fork Gualala River, and McKenzie Creek in the upper South Fork (Fox and Quinn,1964; Rowell and Fox, 1964; Parke and Klamt 1970; Parker and Pool, 1964a; Parker and Poole, 1964b; Parker and Poole, 1964c).
Coho salmon were still in the sport catch as of 1972-73 (Boydstun, 1973) and over 800 coho were landed by anglers (Figure 1). Downstream migrant trap results from 1974 in Big Pepperwood Creek suggest their place in the fish community was declining (Figure 2).
Figure 1. The picture at left was taken in 1972 and shows two anglers, the one at left with a female coho salmon and the one at right with four steelhead of varying size, all caught on the Gualala River. The bag limit was three each for coho salmon and steelhead.
Figure 2. Results from a California Department of Fish and Game downstream migrant trap operated in 1974 in Big Pepperwood Creek, tributary to the lower South Fork Gualala, are shown at left. Although coho salmon juveniles were still present, they were at very low levels. The fish community had a much larger component of roach than coho or steelhead.
Coho salmon have been found only in the North Fork Gualala since 1980. They were present in the years when hatchery fish were planted or immediately after the first brood cycle of returning hatchery adults (Higgins, 1997). Extensive dive surveys in 2001 failed to find any coho in the Gualala River basin and CDFG (2002) noted that coho salmon were "extirpated or nearly extirpated" in the Gualala.
The California Department of Fish and Game did extensive creel surveys on the Gualala River in 1953-1955, 1962 and 1972-1976 (Figure 3). Documented adult steelhead catch was as high as 1700 and adult steelhead runs were estimated for 1974-1976 (Boydstun, 1976a, 1976b). The 1974-75 steelhead run was estimated at 7608 (6126-10379 95% CI) and 6300 in 1975-76. Boydstun (1974a) noted that while angler effort in 1972-73 was 60% greater than in 1953-55, the catch in the 1970's was just 25% of the 1950's catch. He attributed the decreased catch rate to decreased adult steelhead abundance.
Figure 3. The chart at left shows sport angling catch rates of adult steelhead for 1953-55, 1962 and 1972-76. Catch rates were much higher in 1953-54 and 1962 than in all years in the 1970's. In contrast to the four hours it took an angler to catch a steelhead in 1953-54, it took about fifty angler hours to catch a steelhead in 1972-73. Angler effort and success may be impaired by high flow conditions and associated turbidity.
Long term electrofishing records for the lower Little North Fork Gualala River show a declining trend for juvenile steelhead standing crop and density from 1988 to 1999 (Figure 4). These surveys are particularly valuable because they measure 100 foot reaches and use block nets to quantitatively sample. Coho were present only in 1988, which was during a period when hatchery fish were being planted.
Figure 4. Long-term electrofishing data collected by CDFG in the lower Little North Fork show samples dominated by steelhead young of the year but with yearling and two year old fish present. Steelhead decreased in number and density, particularly since 1992. This is not consistent with flow and water years, as 1992 was at the end of a five year drought and years since 1995 have been wet. Wet years should have increased available habitat and standing crops.
CDFG did habitat typing surveys of 100 miles of the Gualala River and its tributaries and collected correlative biological samples in 2001. The California Salmonid Stream Habitat Restoration Manual (CDFG, 1998) says such electrofishing samples should "provide a general assessment of fish presence, distribution and habitat utilization within a stream.... Relative abundance of a species may suggest trends in past or future population numbers." The 2001 CDFG surveys found a paucity of older age steelhead juveniles and many reaches dominated by Gualala roach (Figure 5), which is indicative of a shift toward water temperatures that are unfavorable to salmonids. Extensive reaches of the Gualala River and its tributaries which formerly supported steelhead juveniles in summer were found to be dry in 2001 (Figure 60.
Figure 5. California Department of Fish and Game electrofishing in September 2001 showed that the Wheatfield Fork Gualala River had almost no steelhead juveniles and that Gualala roach dominated the fish community. This suggests a diminished abundance of steelhead in the Wheatfield Fork Gualala River.
Figure 6. This chart shows the relative length by habitat type in the Gualala basin according to 2001 surveys. Fourteen of seventeen streams surveyed had reaches that lacked surface flows. Major loss of habitat has occurred in many Gualala Basin tributaries and extensive dry reaches constitute a reduction for juvenile steelhead with regard to distribution.
Loss or substantial reduction of other fish species, such as the eulachon and the Sacramento sucker is further evidence that the Gualala River is well outside its natural range of aquatic habitat variability. The extensive reaches of the river and its tributaries that lack surface flow because of aggradation present a challenge for survival even to the hardy Gualala roach.
The following is a list of Topics in KRIS Gualala where you can see data in its context, Metadata and associated Info Links. The large-case letters in parentheses indicate KRIS sub-basins.
(MG) Tour: Sport fishing in the Gualala River and Lower River
(SF) Fish: Downstream Migrant Catch by Week Pepperwood Creek 1974
(MG) Fish: Adult Steelhead Catch per Unit Effort 1953-55,1962-63 & 1972-76
(NF) Fish: Lower Little NF Gualala Fish Community, 1988-1999
(WF) Fish: Lower/Mid/Upper Wheatfield Fork Gualala E-fishing, 2001 by CDFG
(MG) Habitat: Habitat Types by Percent Survey Length (All)
The observed change in the distribution and abundance of coho and steelhead is within the natural range of variability.
Ocean conditions and fishing are known to have caused variable ocean survival off the Pacific Northwest coast with attendant cycles in abundance for coho salmon (Finney et al., 2000). See Higgins (1997) for a fuller discussion of potential impacts of these factors on Gualala River fish stocks. Given the lack of long term trend data for adult coho salmon, some contend that a decline in the species can not actually be established (Ellis, 1997).
Monitoring Trends to Test the Hypotheses
To see if salmon and steelhead populations are, indeed, just in natural remission and will rebound in the future, fish surveys like spawner and redd counts, creel census, downstream migrant trapping and more widespread electrofishing should be conducted.
Boydstun, L. B. 1973. Progress Report for Coastal Steelhead Study. California Department of Fish and Game. 2 p.
Boydstun, L. B. 1974a. Project Progress Report Coastal Steelhead Study. June 1, 1972 to June 30, 1973. California Department of Fish and Game Project No. AFS-16-2.32 p.
Boydstun, L. B. 1974b. Coastal Steelhead Study. June 1, 1973 to June 30, 1974. California Department of Fish and Game Project No. AFS-16-1.32 p.
Boydstun, L. B. 1976a. Coastal Steelhead Study. July 1,1974 to June 30,1975. California Department of Fish and Game Project No. AFS-16-3. 8 p.
Boydstun, L. B. 1976b. Coastal Steelhead Study. July 1, 1975 to June 30, 1976. California Department of Fish and Game Project No. AFS-164. 12 p.
Boydstun, L.B. 1977. California's steelhead program. in T. Hassle and R. Van Kirk, eds. Proceedings of the genetic implications of steelhead management symposium, 1977. Calif. Coop. Fish. Res. Unit special report 77-1. pp. 26-30.
Bruer, RR 1953. Field correspondence to Inland Fisheries Branch, Region III recommending Gualala River be opened to sport fishing after closure for five years. Files at Region 3, Yountville, CA. 1 p.
CA Department of Fish and Game. 2002. Status Review of California Coho Salmon North of San Francisco. Report to the California Fish and Game Commission. California Department of Fish and Game, Sacrament , CA. 336pp. http://www.dfg.ca.gov/nafwb/pubs/2002/2002_04_coho_status.pdf. (Caution, large file).
California Resources Agency. In Review. Gualala River Watershed Synthesis. CA Dept. of Fish and Game, State Water Res. Control Bd., CA Dept. of Water Resources, CA Div. on Mines and Geology and CA Dept. of Forestry. Sacramento, CA. Draft released January 16, 2001.
Ellis, R. H. 1997. Comments to National Marine Fisheries Service regarding the proposed listing of coho salmon as threatened in the Southern Oregon/Northern California ESU. Submitted on behalf of: California Forestry Association and California Forest Resources Council, Sacramento, CA. 41 p.
Finney, B.P., I. Gregory-Evans, J. Sweetman, M.S. Douglas, J.P. Smol. 2000. Impacts of Climatic Change and Fishing on Pacific Salmon Abundance Over the Past 300 Years. Science. 2000, Oct 27; 290 (5492):795-799.
Fox, B. and W. Quinn. 1964. North Fork Buckeye Creek Stream Survey, personal observations. North Fork Buckeye Creek surveyed from headwaters to mouth on foot, total distance 5 miles (hand drawn map). August 1964. California Department of Fish and Game, Region 3, YountviIle, CA 2 p.
Fox, B. 1964. Wheatfield Fork Stream Survey. Wheatfield Fork surveyed by foot from the headwaters to the mouth of Redwood Creek, a total of 6.8 miles. September 28, 1964. California Department of Fish and Game, Region 3, Yountville, CA. 2 p.
Kimsey, J. B. 1953. Population Sampling of Three North Coastal Streams Closed To Summer Trout Fishing-1952 Season. First Progress Report. California Department of Fish and Game. 15 p.
Higgins, P.T. 1997. Gualala River Watershed Literature Search and Assimilation. Funded by the Coastal Conservancy under contract to Redwood Coast Land Conservancy. Gualala, CA. 59 pp.
Parke, C.W. and R. Klamt. 1970. Fuller Creek Stream Survey. Fuller Creek from mouth to forks 2.8 miles upstream on foot (hand drawn map, description and dimensions of log jams).June22, 197O. California Department of Fish and Game, Region 3, YountviIle, CA. 2 p.
Parker, C. and R.L. Pool. 1964a. Haupt Creek Stream Survey Haupt Creek surveyed by foot from the headwaters to the mouth, a total of 3.75 miles (hand drawn maps, field notes). August 25, 1964. California Department of Fish and Game, Region 3, Yountville, CA. 2 p.
Parker, C. and R.L. Pool. 1964b. North Fork Gualala River Stream Survey, North Fork Gualala River surveyed by foot and automobile from the mouth to the headwaters, a total of 15 miles. September 17-18, 1964. California Department of Fish and Game, Region 3, Yountville, CA. 2 p.
Parker, C. and R.L. Pool. 1964c. McKenzie Creek Stream Survey. McKenzie Creek from mouth to headwaters on foot, total length 4.25 miles. September 23-24, 1964. California Department of Fish and Game, Region 3, Yountville, CA. 2p.
Rowell, J., and B. Fox. 1964. Fuller Creek Stream Survey. Fuller Creek from mouth to forks 4.25 miles upstream on foot and by vehicle (hand drawn map, description and dimensions of log jams). August 18-l 9, 1964. California Department of Fish and Game, Region 3, Yountville, CA. 2 p.
Spacek, K. 1997. Letter to Pat Higgins re: Gualala River Watershed Literature Search and Assimilation. Resident of Annapolis, CA and life long Gualala River angler. 6 p.
Taylor, S.N. 1978. The status of salmon populations in California coastal rivers. California Department of Fish and Game. Salmon/Steelhead Program, Anadromous Fisheries Branch. 14 pp.