LIFE HISTORY, DISTRIBUTION, RUN SIZE, AND HARVEST OF SPRING CHINOOK SALMON IN THE SOUTH FORK TRINITY RIVER BASIN (CONTINUED)
Eleven individual creel surveys were conducted during July 1992. Thirty-two creel surveys were conducted between 23 May and 28 June 1993. We interviewed 21 anglers who fished a total of 28.5 hours. No chinook salmon were creeled, and no tags were returned. We found that fishing pressure from May through July was highest in the Hyampom area, and that the target species was primarily juvenile steelhead (which most fishermen identified as trout). Based on these data, we estimated that the legal angler harvest of spring chinook in the SFTR during the summer of 1992 and the spring of 1993 was zero.
We certainly did not monitor all angling activity, since CDFG staff who reside in the Hyampom area reported that one local angler claimed to have caught and released "nine or ten" salmon, including one tagged fish, from the Hyampom area in July 1992. The local CDFG Warden confirmed this report.
The use of tag returns to generate angler harvest estimates is not always effective. Several local anglers told Project personnel they seldom, if ever, returned tags, even if a reward was offered. Some anglers told us that they have tags from steelhead they intended to return but "keep forgetting". Other researchers have noted similar problems (Butler 1962; Green et. al. 1983; Konstantinov 1978; Paulik 1961). Therefore, the simple lack of tag returns should not be used as documentation for lack of harvest. Consequently, we will rely more heavily on creel surveys, and less so on tag returns, to meet our objective of determining angler harvest.
During the 1993 season, we operated the Gates Weir for 34 days, between 24 June through 31 July. High river flows and late spring storms prevented us from installing the weir earlier. Spring chinook immigration continued more or less undiminished throughout this period and was still underway when we were forced to suspend operations due to excessively warm minimum water temperatures (>18.5 oC). During this period only immigrant (upstream migrating) fish were trapped, while emigrant fish were allowed to pass through the weir via a narrow fyke.
We captured and released 31 adult and 31 grilse spring chinook salmon and 42 adult spring-run steelhead. For comparison, last season we captured 49 spring chinook and only 16 spring-run steelhead. The weir was operated this season for just over one-half as long as last year and captured 27% more fish. Since an emigrant trap was not installed, no out-migrant (spawned) adult winter-run steelhead were captured (Table 4). Spring chinook captured at the Gates Weir ranged in size from 34 to 69 cm FL (Figure 11). The average FL was 52.4 cm, significantly smaller than the 59.8 cm average of last season (X2 = 1.5). This average size difference was due to the higher proportion of grilse and the absence of fish over 70 cm FL during the 1993 season.
TABLE 4. Trapping summary for the Gates Weir by Julian week from 24 June through 31 July 1993. The Gates Weir is located in the South Fork Trinity River 32 kilometers upstream from the mouth.
|
Immigrant trap a/ | ||||||
|
Spring-run chinook salmon |
Steelhead | |||||
|
Julian week |
Start date |
Adults |
Grilse b/ |
Winter-run c/ |
Spring-run d/ |
|
|
25 |
6/18/93 e/ |
3 |
0 |
0 |
0 |
|
|
26 |
6/25/93 |
7 |
9 |
0 |
6 |
|
|
27 |
7/02/93 |
3 |
4 |
0 |
9 |
|
|
28 |
7/09/93 |
6 |
5 |
0 |
7 |
|
|
29 |
7/16/93 |
4 |
5 |
0 |
12 |
|
|
30 |
7/23/93 |
6 |
7 |
0 |
7 |
|
|
31 |
7/30/93 |
2 |
1 |
0 |
1 |
|
|
Totals: |
31 |
31 |
0 |
42 |
||
|
a/ Due to late date of weir installation, emigrant trap was not installed. b/ Grilse are chinook measuring < 53 cm, adults are > 53 cm. c/ Winter-run steelhead are upstream-migrating, sexually-mature fish. d/ Spring-run steelhead are upstream-migrating, sexually-immature fish. e/ Trapping actually began on 6/23/93. | ||||||
While 62 spring chinook were captured, only 51 were tagged with anchor tags and marked with a 2RV fin-clip. Spring chinook which appeared lethargic or severely stressed were released untagged and unclipped. One chinook was known to have shed the anchor tag and four weir mortalities were found. Therefore, we effectively tagged 46 spring chinook at this weir. Thirty-eight of the 42 spring-run steelhead captured were given a 2LV fin clip.
Since high river flows delayed installation of the Gates Weir, we also tagged spring chinook at the Forest Glen Weir in 1993. We installed this weir on 11 May and tagged spring chinook there until 31 July. It was operated until 31 August to recapture Gates Weir-tagged fish. We captured 44 spring chinook (27 females, 17 males) and 49 steelhead (14 spring-run and 35 downstream-migrating winter-run) during 101 days of operation. We effectively tagged 21 spring chinook at this site.
During the 1993 adult trapping season, we examined 62 spring chinook and 42 spring-run steelhead at the Gates Weir. Only 19.3% of spring chinook showed scars this year, compared to 28% last year (Table 5). Similarly, 9.5% of the steelhead had scars this year, compared to 41% last year. These numbers are not significantly lower for spring chinook, but are significantly lower for steelhead (X2 = 0.46, X2 = 6.5, respectively).
Precipitation during this past season was near-to-above normal, and river flows were correspondingly higher. Water clarity was below normal. These factors certainly contributed to lower in-river fishing efficiencies (both gill-net and hook-and-line) resulting in a lower incidence of associated scars. The occurrence of predator scars was virtually the same for spring chinook, but less than one-half of last year's total for steelhead.
In the interest of clarity and continuity, further analysis and discussion of the above data will be covered in the next annual report (1993-94) where these spring chinook will be followed through the end of their spawning season.
TABLE 5. Summary of scars observed on steelhead and spring-run chinook salmon captured at the Gates Weir in the South Fork Trinity River during the 1993 adult trapping season.
|
Steelhead |
Spring-run chinook salmon | |||
|
Scar types |
Number with scar type |
Percent of total with scar type |
Number with scar type |
Percent of total with scar type |
|
Gill net a/ |
0 |
0 |
2 |
3.2 |
|
Fresh-hook b/ |
0 |
0 |
0 |
0 |
|
Ocean-hook c/ |
0 |
0 |
0 |
0 |
|
Predator d/ |
4 |
9.5 |
7 |
11.3 |
|
Unknown e/ |
0 |
0 |
3 |
4.8 |
|
a/ Gill-net scars are defined as nicks in the leading edge of the dorsal or pectoral fins, usually accompanied by individual or multiple lines on the sides of the fish. b/ Fresh-hook scars are unhealed perforations or tears around the mouth which result from the fish being hooked in fresh water. c/ Ocean-hook scars are healed hook scars, usually accompanied by noticeable scar tissue. d/ Predator scars are longitudinal scratches or inverted "v"-shaped marks along the body of the fish, usually spaced close together and may be accompanied by scale loss. e/ Unknown scars are those which do not fit any of the above categories. |
1. Continue using color-coded tags which allow for the identification of individual fish during snorkel surveys, and especially during follow-up observations at holding pools and during redd surveys.
2. Consider moving the SFTR recovery weir nearer to Hyampom in an effort to recapture more marked fish which would allow for a more valid population estimate, or discontinue using this weir for recapture.
3. Poor spawning gravel permeability and bedload movement may be affecting spring chinook salmon egg and alevin survival. Additional studies are needed in this area.
4. Major and minor landslides are adversely affecting juvenile rearing habitat in the SFTR. Studies are needed to quantify this effect.
Chapman, W. M. 1943. The spawning of chinook salmon in the main Columbia River. Copeia. 1943: 168-170.
Cramer, F. K., and D. F. Hammack. 1952. Salmon research at Deer Creek, California. United States Fish and Wildlife Service. Special Scientific Reports, Fish. No. 67. 16 p.
Butler, R. L. 1962. Recognition and return of trout tags by California anglers. Calif. Fish and Game, 48: 5-18.
Dean, Michael. 1994. Life history, distribution, run size, and harvest of spring chinook salmon in the South Fork Trinity River. Chapter VII. Job VII. pp. 191-227. In: K. Urquhart and R. M. Kano (eds.). Annual Report of the Trinity River Basin Salmon and Steelhead Monitoring Project, 1991 - 1992 Season. February 1994. 235 p. Available from Calif. Dept. of Fish and Game, Inland Fish. Div., 1416 Ninth Street, Sacramento, CA 95814.
Green, A. W., G. C. Matlock, and J. E. Weaver. 1983. A method for directly estimating the tag-reporting rate of anglers. Trans. Am. Fish. Soc. 112: 412-415.
Groot, C., and L. Margolis. 1991. Pacific Salmon Life Histories. UBC Press. University of British Columbia. Vancouver, B.C., Canada. 564 p.
Konstantinov, K. G. 1978. Modern methods of fish tagging. J. Ichthyol. 17(6): 924-938.
LaFaunce, D. A. 1967. A king salmon spawning survey of the South Fork Trinity River. Calif. Dept. of Fish and Game, Mar. Res. Admin. Rep. No. 67-10, 1964. 13 p.
Lindsay, R. B. 1985. Study of wild spring chinook salmon in the John Day River system. Oregon Dept. of Fish and Wildlife. 119 p. Available from Bonneville Power Administration, Div. of Fish and Wildlife, P.O. Box 3621, Portland, Oregon 97208.
Lindsay, R. B., and B. Jonasson. 1989. Spring chinook salmon in the Deschutes River, Oregon. Oregon Dept. of Fish and Wildlife. Fish. Div. Information Reports, 89-4. 92 p.
Mattson, C. 1948. Spawning ground studies of Willamette River spring chinook salmon. Oregon Fish Commission Resource Briefs. (12): 21-32.
Paulik, G. J. 1961. Detection of incomplete reporting of tags. J. Fish. Res. Bd. Can. 18: 817-832.
Ricker, W. E. 1975. Computation and Interpretation of Biological Statistics of Fish Populations. Bull. Fish. Res. Bd. Can. No. 191. 382 p.
Snyder, J. O. 1931. Salmon of the Klamath River, California. Calif. Dept. of Fish and Game, Vol. 10, No. 4, pp. 163-172.
Sullivan, C. 1989. Juvenile life history and age composition of mature fall chinook salmon to the Klamath River, 1984-1986. Master's Thesis. Humboldt State University, Arcata, California 95521. 69 p.
Zuspan, M. 1992. Salmon spawner surveys in the upper Trinity River basin. Chapter I. Job I. pp. 1-29. In: K. Urquhart (ed.). Annual Report of the Trinity River Basin Salmon and Steelhead Monitoring Project, 1989-90 season. June 1992. 140 p. Available from Calif. Dept. of Fish and Game, Inland Fish. Div., 1416 9th St., Sacramento, CA 95814.
APPENDIX 1. Other sources of data.
APPENDIX 2. List of Julian weeks and their calendar date equivalents.
