C05__Attachment_7_Biological_Investigations_of_the_Fishery_Resources_of_TR__CA_1950.pdf

1~11uTY Ri VEN BASIN

RESOURCE LIBRARY

RINITY COU ''T'Y LI . ~"Y

WEAVER l- E, c.,;•' ., BIOLOGIC.AL lNV'ES TI(}ATIO,Vg

OF THE

FlGHEI?Y RESOURCeS

OF TRINITY R\VfRJ C!.AL1FDRrv'It\ '

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TRINITY RIVER BASIN

RESOURCE liBRARY

Preface

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United States Department of the Interior Oscar L. Chapman, Seoretary Fish and Wildlife Service Albert M., DaJr~ Director

Special Soientific Report ~ Fisheries No. 12 c

BIOLOGICAL INVES TIGA 'l'IONS OF THE FISIIERY RESOURCES

OF TRHTI 'fY RITI:R, CALIFORNIA

By

James w. Moffett and Stani'ord H. Smith Fishery Research Biologists

CON'IENW

Introduction ..... .. • • e • • • • • • • • • • $ • • • • • •

Phyaical characteristics of Trinity Ri vor • • • • • .. • • • • • Run~off and flow • • • e • • • Q • • a e e • • e 0 • • •

River temperature ...... " •• " • • c • • • • • • • o o

Existing biological condit~onse •• •• o • • o •• ~ • • •••

Non-game fishes •••••• ~ ••••• o ••••• • o • o

Resi~ent game fishes • • • • • • • • • • • • • • • • • • • Anadromous fishes ••••••• ~ • o • • • u o o • o • o •

King sa~on o • • • • • • ~ • • • • • • • • • e • • • Commercial and apor~ fisheries •• e • o • •••

Characteristic& of the seasonal runs •• e • o o

Spawning and development o • • • • • • o • D • •

Seaward migrationo e •••••• 5 •••••••

Sox ratios of adults •••••• ••• • ••• o

Silver salmon ~ • • • , • • • • ~ • • • • • • • • • • Steelhead t rout ••••••••••• •••••••• Pacific larr.prey • e • 0 ~ •••••• ••••••••

Salmon spawning bed survsys ••• ~ • ••••••••••••• Nest measurements. • o • .. • . • . • • • • • • • • • • • • • •

Methods ..... ... e ••••••• •••••••••••

Results of surveys ••••••••••• ~ ••••••• • Eff'ectn ·or tra.tel"' development plans on the Trinity

River fishery and suggested meo.ns fe r fish protection ••• ., Ger ... era.l p.M.noiples of operation ... ., ••••••• ~ ••• Maintenance plans for Lewiston Dwm 8 ••• ~ ••••• ~ •

Development of addi tio:u.al spe.wning grounds in tha ms.i:n stream •• ., •• " •••••• ., • Improvemon t of 'cri bute.ry s treruns . • • • • • e • • • •

Arti ficial prepara tion ••• •• o • , •• o •••••

Maintenance pls.na for Brovma Creek de.m • • • • .. • • • • • Steelhead maintenance. e •• • G • " ~

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ILLUSTRATIONS

FIGURE

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1. Chart of Trinity River Watershed. • • • • • • • • • • • 3

2. Avert:tge monthly flow of Trinity River at Lewiston during water years 1928-1942 •••••••••••••• 7

3. Ave~ monthly discharge of Trinity River at three points in the drainage. Water years 1932-1939. • ••• 8

4. Trinity River water temperatures recorded at Lewiston during the period: November 1942 through July 1946 •••••••••••••••••••• 11

5. Numbers of adult king salmon passing through the Lewiston weir in 1942, 1944,. 1945 and 1946, Trinity River.

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Seaward migration of young king salmon in 'lrini ty River at Lewiston •••••••••••• o ••• • • •

Length-frequency distribution of male and female king salmon from two different sections of Trinity Rivera •

B • . Downstream migration of steelhead trout in Trinity River at Lewiston. • •••••• • •••••• • • • •

9. Average lengths of steelhead trout young taken in fyke nets from Trinity River at Lewiston, arranged aaoording to brood years and time of capture. • • • • 44

10. Number of salmon nests in Trinity River between Lewiston and North Fork as determined at two different river flows. • • • • • • • • • • • • • • • • • • • • • 53

11. Number of salmon nests in Trinity River between Lewiston and North Fork, as related to a constant change in availability of gravel at various river flows •••• • 55

12. Recommende d fixed flow schedule for Trinity River at Lewiston and its relation to the life history phenomena of king salmon in that stream ••• • • • •• e • • • • 59

13. The e.ffeot of a fixed flow schedule for fish at Lewiston on the discharge of Trinity River at various points downstream •••••••••••• • • • ••• • • • • 51

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ILLUS '!'RATIONS

FIGURE

1. Chart of-: Trinity River Watershed. • • • • • • • • • • • 3

2. Avor~ge monthly flow of Trinity River at Lewiston during water years 1928-1942 •••• • •••• • •••• 7

3. Ave~ monthly discharge of Trinity River at three points in the drainage. Water years 1932-1939. • •• • 8

4. Trinity River water temperatures recorded at Lewiston during the period: November 1942 through July 1946 •••••••••••••• 0 • • • • .11

5. Numbers of adult king salmon passing through the Lewiston weir in 1942, 1944, 1945 and 1946, Trinity River. • • • • • • • • • • • • • • • • • • • • • • • • 24

e. Seaward migration of young king salmon in Trinity River at Lewiston •••••••••••••••• • • • 29

7. Length-frequency distribution of male and female king salmon from two different sections of Trinity River. • 37

8 • . Downstream migration of steelhead trout in Trinity River at Lewiston ••••••••• • • • •••• • • •

9. Average lengths of steelhead trout young taken in tyke nets from Trinity River at Lewiston, arranged aooording to brood years and time of capture •• • • •

10. Number of salmon nests in Trinity River between Lewiston and North Fork as detennined at two different river flows. • • • ••• • • • • • • • • • • • • • • •

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11. Number of salmon nests in Trinity River between Lewiston and North Fork, as related to a constant ohange in availability of gravel at various river flows •••• • 55

12. Recommended fixed flow schedule for Trinity River a.t Lewiston and its relation to the life history phenomena of king salmon in that stream •••••••••• • • • 59

13. The e.ffeot of a fixed flaw schedule for fish at Lewiston on the discharge of Trinity River at various points downstre~ •••••••••• ~ ••• • • • • • • • • 51

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INTRODUCTION

I Demands for additional water supplies for irrigation and pro-duotion of hydroelectric power in 'the Central Valley and adjacent areas in Calif'orni.~, foous ed attention on the upper Trinity River drainage as a possible source of supply. Plans to divert Trinity River water into Sacramento Valley from that area were formulated and published in 1931 as a part of the california State Water Plano These plans were further studied and refined by the u. s. Bureau of Reclamation and u. s. Army Corps of' Engineers and by 1941, their realization seemed certain. It was also apparent that diversion of Trinity River water would seriously affeot the fishery resources that are dependent upon the upper river, particularly king sa~on and steelhead trout. In order to determine the rnagni tude and biological characteristics of these resources and to design management plans and procedures for their protection, the u. s.

Fish and Wildlife Servioe conducted a comprehensive survey and study of the entire problem. Major features of the study involved determination of: (1) the size and composition of fish population, (2) the character istics of the seaward migration of young salmon and steelhead trout, ( 3) the extent and utilization of spawning gravels, ( 4) the physical characteristics of the drainage, (5) existing biological conditions, and

(6) possible means of controlling the fishery and its environmental factors.

Work was first started in the fall of 1942 when a temporary fish counting weir was constructed on the Trinity River a few hundred yards below the river bridge at Lewiston (see map) and approximately 105 miles upstream from the river's mouth. Studies of some of the biological and physical conditions of the stream were also started during November of 1942. The temporary fish counting weir was replaced with a removable structure in late 1943. Because of wartime impediments, uninterrupted studies of the Trinity River fishery covered a period of on~y .. two years.

As a result, it is impossible to make positive and final conclusions.

This report, therefore, is an interim report with most findings and con clusions subject to possible revision pending further investigational findings.

Trinity River. l argest of the Klamath River tributaries, rises in the Scott Mountains at the northern end of Trinity County, california.

It courses south and west through Trinity County, then north to its con fluence with the Klamath River in Humboldt County. The less canyonous portions of the river bed abound with broad gravel riffles and provide excellent spawning grounds for king salmon. Numerous small tributaries and the upper part of the main stream furnish adequat~ spawning ground for large numbers of anadromous and resident trout. Like many of the rivers in the northern california, its run-off pattern consists of extremes in flood and in drought. During summer, its flow is extremely low. In winter and spring, it rages destruc:tively when in flood and discharges much of its annual run-off •

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The Trinity and its parent stream, the Klamath, have been fish-ing grounds for Indian tribes for ages. Well established trada routes from the interior to the sea passed through or terminated in the Klamath and Trinity country where a lively oommeroe in shells and dried fish existed. Thousands of king salmon, silver salmon, and steelhead trout ere caught by the Indians living in Klamath and Hoopa territory (Hewes, 1942). These Indians were highly skilled in fishing. They constructed fish weirs of logs, poles, and brush across the rivers and speared or netted the upstream mlgrant salmon, trout, and even lampreys. These weirs r emained -in the stre~s as virtually impassable barriers until the first rains of autumn replenished river flow sufficiently to wash them away.

Year after year the weirs were installed according to strict ritual and procedures (Snyder, 1924). In modern times, most of the fi s h weirs have disappeared. One is usually built each summer at Hoopa on the lower Trinity River and below it the Indians seine, spear, or operate gill nets.

Salmon and steelhead are dried, smoked, canned in the Reservation ce.nnery, or used fresh. The Indians praotice conservation of a sort1 part of the migrating salmon are allowed to pass the weir through gate11 installed for t hat purpose.

Trinity River has long been famous as a gold-bearing stream.

In earl y times, some rather large communities occupied its banks and most of the presently existing towns are remnants of these settlements whi oh degenerated following exhaustion of the major placer and hard-rock gold deposits. Extensive gravel deposits above North Fork have been dredged for golde Great spoil piles of barren gravel constitute the immediate strewn bank for mile upon monotonous mileo The original character of the stream and its adjacent flats has been seriously altered.

Same isolated dredge operations still go on in the drainage and, at times , the s t ream bears great quantities of silt in much the same manner as i t did fo r 76 years or more follavdng the discovery of gold.

A vigorous commercial fishery on Klamath River began shortly after gold-mining started. The early fishing efforts were for local supplies and usually concentrated on the riffles of the rive r and its tributaries. Canneries began operating on the Klamath estuary prior to 1892 and reached a high state of developnent by 1912 (Snyder, 1931) • Ove r -fishing and possibly mining soon made noticeable changes in the abundance of king salmon. Early records given by Snyder indicate a his t orical peak in the Klamath River commercial fishery occurred in 1912 when over 1,384,000 pounds of fish were packed from a ~atch of approximately 141,000 salmon. Records for that year are incomplete and consist of estimates applied to portions of unreported packs . The 1915 paok is recorded more completely; about 1,232,229 pounds of salmon .,rere packed from a catch approximating 72,357 king salmon.

Essential features of the Trinity development plan oons i s t of an earth-fill storage dam about 352 feet high, built in the vi cinity of Fairview ouartz Mill (see map)J a divers ion dam about 110 fee t high located just above the town of Lewiston, california; and a series of y

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U. S. Fish and Wildlife Service Centrul Vulley Investigations

TRINITY RIVER WATERSHED

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Trinity und Humboldt Counfie s CALl FORNIA

0 5 IOmiles

SCALE

tunnels; power plrmts, and canals leading fro:n the diversion dam to the Sacrnr.lOnto River a'~Jove Keswick Dam. A second plan contemplates con struction of a storage dam near Browns Creek, some 6 miles below Douglas City. Wa. tar from this reservoir would be pumped to the di vorsion tunnel abo...-e Lewis ton. The point of diversion from the Trinity River at Lewiston is about 1300 feet above the Sacramento River.

Dams at the Fairview and Browns Croak sites woulj be high barriers insur.nountable by present type of fish ladders. Reservoirs formed by t hese da..rns would be very long, extensive, and would cover much of the axis t1.ng spawning grounds of anadromous fishes. These fishes might be lifted mechanically over the dams, but it is doubtful that their offspring would pass through the reservoirs, find the river outlets, and proceed dovmatream without suffering 111B.terial losses. Mos-c of the water would fl~N into the diversion tunnel and with it the majority of the youDg salmon and trout produced upstream.

Al!T'.ost without exception., Trinity River saL-non migrating above the South For.lf_spawn in the 72 miTeB"'·o·r'- river -· batween the -North Fork and Ramshorn Creek. In addition to the main river, tltree tributaries are used by spawning salmon. A dam at the Lewiston site would cut off 35 miles of the main river and all of Stuart Fork, the most important sp~wning tributary. The salmon would be blocked from approximately 50 percent of the_!_! na. tural SP!i'Wl}in_g_gr,q_u~~-!n _the U..PP.er__tr:ilrl:.ty..!. A da mat the Browns Creek site would cut off the remaining two spawning tribu~aries and 59 miles of the main river spawning area. This d&m would eliminate ~e 82 percent of the natural salmon spawning area .

Appreciation is expressed for the help given by the State of

California Division of Fish and Game and by many persons - who were connec ted with the work from time to time. Among these were Dr. Paul R. Needham, who directed the project unti l the end of 1944, Harry A.

Ranson. George Warner, Owen Vivian, William H. Davenpor t, Mi llard Cbots, Donald Drake, s. N. McKinsey, Norma.n Mattoon and many residents of Lewiston who assisted with work on the project. Much of the infor• mation included has been generously supplied by the u. s. Bureau of Reclamation, u. s. Engineers, u. s. Forest Service, and the u. s.

Geological Survey. The Indian Agency at Hoopa.. on the lower Trinity River, also cooperated.

This investi gati on was supported by funds transferred to the Fish and Wildlife Service by the Bureau of Reola.ma.tion. It was considered a vital part of the pre-project engineering and exploratory work con ducted by the Bureau of Reola.ma.tion. The study was terminated in August 1946, when the Bureau of Reclamation oeased active work on the Trinity River diversion project.

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PHYSIC!\.L CHARACTERISTICS OF l'RINI'IT RIVER

~·tnity River is approximately 159 miles long and drains a semi wilderness area of approximately 2,900 aquare miles. It is divided into five more or lass distinct sections which have a direct bearing on the utilization of the stream by spawning and juvenile anad~omous fisheso Th9 upper.most 18 miles of the river from its source to Ramshorn Creek are precipitous (gradient 222 ft./mile), the channel is narr~, gravel riffles are very liroi ted, and the bottom is covered with large boulders • The 12 rni les of river between Rrunahorn Creek and Trinity Center traverse a broad valley into which many small tributary streams enter. The stream has a gradient of 58 feet per mile and meanders through wooded and pasture lands wherever gold dredges have left the original terrain. Its ~hannel is broad and gravelly with large extensive riffles alternating with deep pools. From Trinity Canter to North Fork, the gradient is less se·.·ere (15 ft./mile), water volumes are greater, and very extensive riffles charaoteri~e the channel. Most of the spawning grounds of' salmon are located in this 60-mile section of stream. Betwesn its North and South Forks the river passes through a rocky canyon 40 miles in length. Water flows are concentrated and made turbulent and exceedingly rapid by the narrow confines whi ch typify this canyon. Gradients are more severe (23 ft./mile) and volwnes of flow, in relation to channel capacity, are relatively great. The Trinity between South Fork and its confluence with Kalmath River meanders (gradient 12 ft.JIDile) the l ength of beautiful Hoopa V~l1ey (29 miles) and is characterized by broad gravel riffles alternating with large, deep pools.

Run-off and Flow

The run-off characteristics of Trinity River aro quite similar -to those encountered in most California streams. The great bulk of tho annual run-off occurs in win tor, while summer flows are quite low (Figure 2 Table 1). At Lewiston gaging station the extremes of flow between winter and summer are represented by a high flow of 40,300 second-feat recorded on February 28, 1940, and a low flow of 2 3 second-feet recorded on July 30, 1924 (u. s. Geological Survey data). The average annual run-off is 1,106,454 aore-feet as measured at Lewiston, and 3,811,520 acre-feet at Hoopa, about 10 miles above the mouth.

The run-off pattern of Trinity River at Lewiston varies widely from year to year, although the seasonal wet-dry cycles occur during corre sponding periods eaoh year. The volume of annual run-off from the drainage above Lewiston had a range of approximately 250,000 to 2,500,000 acre-feet, with a mean of 1,106,454 acre-feet, during the years 1912 through 1945.

Day Jan. Feb. Mar.

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TABLE NO. 1

AVERAGE DAILY FLO'« IN CUBIC FEET PER SECOND

TRINI TY RIVER AT LE'i'ITSTON WATER YEARS 1928-1942

Apr . May June July Aug.

Sept. Oct. Nov . Dee.

1 1,547 1,555 3,945 3,435 3,863 2,608 1,017 248 132 137 376 609 2 ·1,626 , 2 ,045 3,249 3, 2 5~ 3, 799 2,607 991 240 148 158 334 1,341 3 1,400 2 ,436 2, 714 3,205 3,694 2 ,549 953 232 141 179 343 1, 347 4 1,437 2, 779 2,526 3,539 3,583 2,592 893 223 136 179 394 733 5 1,171 2,354 2,475 :3,21_'7_ ____ 3,435 2 , 676 857 215 134 163 392 599 6 1,018 -~--;92-9~-268 --z-, 933 3,443 2,635 821 207 133 155 336 522 7 1p028 2,747 2 ,124 3,017 3,447 2,600 790 201 128 150 310 489 8 1,085 2,592 2,134 3,071 3,575 2,425 749 198 126 148 296 481 9 1,166 2, 377 2, 308 2, 982 3, 873 2, 334 724 194: 127 151 536 766

10 1,_].75 - 2,243 2,348 2,917 3,905 2p303 693 189 128 145 510 2,174 n 1, 45o 2,263 2,277 2,993 4,048 2..,346 638 iss 127 142 506 2,893 12 1,191 2,005 2,803 3,032 4,283 2,296 605 182 128 144 388 1,696 13 1,259 1,842 2,770 3,529 4,342 2,201 578 177 131 144 374 1,343 14 1,659 1,720 2,427 3,805 4,359 2,107 561 171 130 163 476 2,250 15 1,940 1,~2_6 __ ~~305 3,953 u 4_,126 _ __ 2 , ro9 540 167 134 175 813 1,859 16 1,464 ____ T;"t46--Z.693 3,723 3,973 2, 468 5l5 164 130 163 655 2,383 .

17 1,281 1,524 2,431 3,428 3,718 1,981 499 161 127 156 663 1~407 18 1,181 1,492 2, 529 3, 454 3, 490 1, 799 464 166 124 153 555 1, 478 19 1,277 1,503 2,751 3,541 3,187 1,659 439 161 125 149 708 1,365 20 1,167 1_,601_ __ 2,60_! _ _ ~?26 __ ·· · _ 3,_344 .• 1,552 417 156 127 142 1,817 1,546 21 1,075 1,972 2,579 3,661 3,589 1,497 403 151 126 190 944 1,485 22 1,201 2,oo8 2, 589 3,631 3,894 1, 471 387 u e 125 199 715 1,261 23 1,579 1,736 2.508 3,699 3,819 1,444 372 144 121 194 1,078 1,174 24 1,723 1,697 2,420 3,677 3,931 1,358 347 141 119 186 715 1,273 25 1,877 1,919 211476 ___ _ 3,518 4. 517 .. _ 1,269 328 138 118 210 578 1,160 26----2~U3 2,143 3,39T~-412 --3,8o4-~--1~T94 310 137 1~o-z-o1 ____ __ .. 578 Y,127

27 2 ,167 3,132 3,801 3,422 3,383 1,154 295 lSS 125 219 506 1,237 28 1, 671 4 , 779 3, 767 3, 565 3,156 1,125 287 134 134 204 531 1. 024 29 1,547 - ---- 3,639 3,757 2,967 1,088 275 134 137 257 654 988 30 1,501 ----- 4,122 3,840 2,821 1,066 265 135 137 256 738 1,072 :sr---1,474 - - --- - 4;J.o6 -~=_-_-:._=_-~:..-~ =-~-,:OJ~~~~-~:=~---=~-..:-~=-===T5s ___ T33-~~ --~ •- -~:.-- ·:sso ___ ~-. -_.::-:---T,2s5 Me an 1, 436.6 2,160.5 2, 8()9;!--~~n.() --- ~3-;o79.0 ___ - r~95't~l- u- -5s'r.·s-l73.-:r- u - - 1~9 ;;-z--179~7-- ---59:3.9 1,30T~1

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Figure 2. Average monthly flow of' Trinity River at Lewiston during water years 1928-1942.

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Figure 3. Average monthly disoharge ot Trinity River at three points 1n the drainage. Water 10ars 1932-1939.

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The general run-off pattern over the entire Trinity dr~inage varies somewhat from that recorded nt Lewis ton. '.M1.e spring run-off pe~k at Burnt Ranch occurs a month earlier than the peak at Lewieton (Figure 3). Inflow from many small tributaries which drain o.n area with little snow accumulation contributes most of the earlier run-off at that point. River flow at Hoopa, including the inflow from New River and the extensive South Fork drainage, reaches a spring run-off peak in March, two months earlier than the peak at Lewiston.

River Temperatures

River tamperatures at Lewi s ton we re recorded daily from November 1942 through July 1946 (Tables 2-5 and Figure 4). Temperatures were taken with a hand thermometer three times each day, at 8 a.m., 12 noon, and at 6 p.m., until January 1945. Following that date, continuous temperatures were recorded by a thermograph. During most of the year, the river reached its maximum t emperature at about 5 p.m., and its minimum at 8 a.m.l consequently, temperatures taken by hand thermometer at these hours closely a pproximate the extremes . Average daily tem peratures after Je.nuary 1945 were conputed from thermograph records by taking the mee.n of temperature readings at two-hour intervals during a 24-hour period.

Trinity River is warmest during July and August when spring and summer salmon are holding over in the main river. The maximum water temperatures and dates of occurrence for years of record are as fo11owss 78Dr., on August 13, 1943; s1Gp., on July 24 and 27, 1944; and 83Gp., on July 27, 1945. Temperature records were not complete enough in 1946 to show the highest temperature with certainty, but a high of so.sor., was reached on July 22, 1946. The maximum temperature recorded for 1943 may not be the true peak tempere.ture for the. t year, as it was taken from partial records made during August and September. A temperature of SOOF., or higher was recorded on 9 days during the summer of 1944 and 27 days during the summer of 1945. As a result of experience gained at Doer Creek Station on Sacramento River, California (Moffett, 1949), aoGp., is considered lethal or near lethal for king salmon. The same ~pecies is able to survive when surface temperatures are above ao<T., in !rinity River by remaining in the cooler waters of deep holes along the river. In August 1944, water at depths over 8 feet in one of these large holes was 7~., cooler than surface water.

The daily temperature range is of interest when considering the effect of maxima as lethal agents. To illustrate this range in Trinity River during summer, the hourly record for July 27, 1945, is presenteds

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12:00 Midnight 74.0 9 rOO A. M. 71.5 5:00 P • M. 83.0 1:00 Ao • 73.5 10:00 A. M. 73.5 6:00 P. M. 82.5 2:00 A.. Me 72.5 11:00 Ao M. 75.0 7:00 Po M. 81.5 3:00 A. Mo 72.0 12:00 Noon 77.0 8:00 p. M. 80.0 4:00 Ao Me 71.5 1:00 P. M. 79.0 9:00 P. v. 79.0 5:00 A. Mo 71.0 2:00 P. M. 81.0 10:00 P. M. 77.5 6:00 Ao M. 70.5 3:00 P. Ma 82.5 11:00 Po M. 76.5 1r00 A. Me 70.0 4t00 Po M. 83.0 12r00 Mid..;

8 rOO A. M. 70.5 night 75.0

During 7 hours of the day, water temperatures were above 800F., while during 11 hours, temperatures were below 75cr. Between 9 a.m. and 4 p.m., the river temperature rose 11.5 degrees, and between 6 p.m.

and midnight it fell 7.5 degrees.

On July 4, 1945, a recording thermometer was installed at Junction City, some 28 miles down riv~r from Lewiston, to determine the warming effect of hot summer weather on the river between these two points.

The maximum, minimum, and average daily water temperatures recorded at this station are given in Tables 6 and 7. A maximum temperature of 85'T-.wa.s recorded at that station on July 27, 1945, the se.me day the peak temperature of 83~ .. was recorded at Lewiston. !he hottest days or the summer were July 26 and 27, when a maximum air temperature of l080F •• was recorded at Lewiston on both days. The river temperaturA r eache d or exceeded socr., on 32 days in the sunmer months at Junction City. During July and August, maximum water temperatures at Junction City ere one or two degrees higher than Lewiston water temperatures for t he corresponding day. Temperature records at Junction City during 1946 were too incomplete for analysis.

EXISTING BIOLOGICAL CONDI 'l'IONS

Non-game Fishes

The Klamath black dace, Rhinichtys osoulus kl~nathensis (Evermann and Meek) , and the fine-scaled Klamath River sucker, Catostomus rimiculus Gilbert and Snyder, are the only coarse fish taken during this study which are known to spend their entire life cycle in the Trinity River.

Both of' these species occur commonly throughout the dre.inage.

The Klamath blaok~ce is the most numerous and ubiquitous species found in the Trinity River. It inhabits all stream sections except the headwaters of' some tributaries. The dace is a small fish in the Trini tyJ the l argest individuals seldom exceed a fork-tail length of 3.1 inches (80 mi l limeters). During the summer low-water period, Klamath black dace are seen i n very large numbers in pools along the river. They are almost

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Vl

I •

T.Al3LE NO. 2

DAILY RIVER TEMPERATURE, TRniiTY RIVER AT LEWIS'.rON

1 9 4 2 1 9 4 3 Nov. Dec. Jan. Feb . l-iar . Apr. May Aug. Sept •

Da.y Bam 5pm Bam 5pm 'Bam 5pm Bam 5pm Bam 5pm Bam 5pm Bam 5pm Bam 5pm Sam 5Pm

1 44 41 In 39 4o 42 43 45 49 48 53 2 53 53 43 44 41 41 4o 42 43 44 47 49 49 52 3 53 53 42 43 41 41 42 43 44 45 47 51 50 52 4 53 52 41 41 41 41 42 42 45 46 48 51 509 5542 68 73 5 52 52 36 41 41 42 42 42 45 4 7 45 45 4 68 74 6 4 7 50 36 38 41 41 42 42 45 45 44 45 49 52 66 74 7 5

1 53 37 39 39 4o 42 43 45 45 43 45 49 52 66 74

8 4 51 38 3 9 39 4o 43. 41 44 45 44 46 49 53 66 76

9 49 50 39 4 38 39 39 39 45 45 45 46 49 53 65 76 10 47 49 41 42 38 39 4o 41 45 45 47 48 51

66 77 11 44 45 41 42 37 38 41 41 45 46 47 50 4 67 77 12 44 43 41 42 37 39 41 41 45 45 48 51 49 52 67 77 13 45 45 41 48 38 38 41 42 46 46 48 52 49 51 67 78 14 47 48 41 43 37 38 4o 42 44 45 48 52 49 50 68 77 15 47 48 41 42 37 38 4o 41 41 44 48 50 67 77 16 46 44 41 42 37 37 4o 43 41 43 49 51 65 75 17 4o 41 41 42 37 37 42 44 43 45 48 51 6655 775 18 43 44 41 41 36 37 42 44 43 45 48 50 4 19 43 44 4o 42 37 37 43 · 44 43 45 47 50 64 74 20 43 44 41 42 35 34 42 43 42 45 46 46 64 74 21 44 44 41 41 34 36 43 43 42 44 46 47 65 72 22 45 46 4o 39 38 38 43 45 45 49 47 49 62 73

~ ~~ ~~ ag ~I jJ . 5~ ~ ~ ~ ~~ ~~ ~ 664~ +7~ ~ ~~ t§ ~~ ~~ a6 a6 t~ ~a ~4~5 §g

~~ a~ 64 7~

,27 45 45 39 39 41 41 44 45 4 46 46 64 28 45 46 39 4o 4o 4o 42 43 45 48 45 48 64

29 46 47 4o 39 44 45 4486 590 4 30 47 4o 4o 39 39 42 42 4 62

64 74 64 74 64 74 65 75 65 75 65 75

31 4o . 4o 39 39 4 4 r 63 74 Av. 46.6 4o.o 38.5 41.2 4a.l 46.7 49.2 65.2 64.9

: . ~ -· t . ~ ..

~- • . I' · --- -- •• '

- i

TABlE NO. 3 1944 DAILY RIVER TEMFERATURE, TRINITY RIVER AT lEWISTON

. . Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

Day Sam 5pm Sam 5pm Sam 5pm Sam 5pm Sam 5pm Sam 5pm Bam 5pm 8e.m 5pm Sam 5pm Sam 5pm 8am 5pm Sam 5pn

· . .. .. ~ . 1 40 40 39 43 50 54 63 68 68 74 65 75 57 66 53 57 44 45

2 40 40 39 45 46 49 50 52 65 68 65 76 65 76 58 68 52 54 41 44 3 40 40 40 43 45 46 48 52 64 69 68 77 64 75 59 62 51 52 41 45 4 40 40 39 40 45 46 50 55 63 69 70 78 65 77 58 68 49 50 42 44 5 40 43 39 42 44 48 55 59 63 68 70 80 66 76 60 66 50 52 43 45 6 43 45 40 43 45 46 59 61 64 68 69 78 67 77 57 65 50 48 43 45 7 43 44 41 45 45 46 58 63 65 74 64 76 67 75 56 66 48 50 43 43 8 43 43 40 43 45 47 55 61 64 70 68 78 67 75 60 66 50 52 42 43 9 40 42 45 47 44 47 55 55 64 68 68 76 66 77 60 65 47 49 41 42

10 40 41 43 47 48 50 54 60 64 73 65 78 67 75 58 65 48 48 40 42 11 39 40 40 45 47 48 58 62 65 75 67 80 65 75 59 63 47 49 40 41 12 38 40 40 45 45 48 55 62 65 73 68 so 65 74 58 61 48 50 39 40 13 37 40 39 41 45 45 56 64 67 75 68 79 64 73 57 65 47 49 37 41 14 38 41 37 41 44 47 55 56 67 73 70 80 64 70 56 66 46 45 38 40 15 38 41 36 43 46 49 52 55 70 76 69 79 61 71 54 63 45 46 38 40 16 37 41 38 45 45 48 44 52 52 54 68 76 68 76 63 69 55 63 42 44 39 40 ... ...., 17 37 41 41 48 44 46 48 50 54 58 69 75 70 78 59 69 55 64 42 45 40 42 18 37 40 45 46 50 52 55 57 69 77 68 76 59 69 54 65 43 44 41 43 19 38 41 43 45 50 55 54 57 70 79 68 78 58 68 54 62 43 46 42 44

20 37 42 42 44 51 57 55 56 70 78 68 77 58 67 54 64 42 44 42 44

.. . a; 21 39 39 41 45 56 55 54 58 70 78 67 77 60 64 57 64 42 45 43 44 22 36 39 43 46 51 55 56 62 69 80 67 76 60 66 57 65 43 46 44 45 23 37 42 43 46 48 54 57 62 70 80 67 75 62 69 56 66 45 47 45 45 24 39 43 43 47 48 57 56 54 68 81 67 75 65 70 54 62 44 45 44 44 25 39 41 43 46 50 57 59 64 70 79 65 77 62 70 54 62 42 45 42 42 , . • -l:

26 36 42 41 45 55 55 58 66 71 79 67 77 62 72 53 60 43 44 40 41 27 40 37 42 42 45 52 56 64 66 75 81 68 80 62 69 52 61 40 42 40 40 28 37 39 39 43 42 47 54 55 64 68 72 79 68 79 62 68 55 60 44 45 40 40 29 39 40 40 42 44 48 52 59 61 69 70 78 67 78 61 65 55 62 44 46 39 40 30 40 41 47 49 54 56 66 71 72 77 67 77 58 67 57 63 46 47 39 40 31 40 43 47 49 54 55 69 78 65 70 55 59 39 41 Av. 39.0 38.9 41.4 45.1 51.1 55.8 67.6 67.5 63.0 56.3 45.9 41.0

40.6 41.3 45. 0 47.2 55.0 59.8 74.9 77.3 ·71.4 63.8 47.5 42.4

(>I

TABLE NO. 4

• 1945 DAILY RIVER TEMPERATURE, TRINITY RIVER AT LEWISTON

January February March April May June

Day Max. Av. Min. Max. Av. Min. Max. Av. Min. Max. Av. Min. Max. Av. Min. Max. Av. Min.

l ' 40 ---- 39* 41 ---- 39* 43 40.8 40 47 44.2 42 54 51.2 47 58 56.0 53 2 40 ---- . 39* 41 ---- 39* 42 40.5 39 45 43.2 40 54 51.3 47 56 55.4 53 3 40 ---- 39* 44

41* 43 40.8 40 46 44 .. 1 41 54 51.4 47 57 55.3 53

·. ~ .. ! 4 40

39* 43 ---- 42* 43 40.6 39 47 44.9 42 55 51.6 47 58 55.6 53 5 41 ---- 40* 44 ---- 42* 42 40.2 38 47 44~6 43 54 51.6 48 , , 56 54.4 52 6 41 ---- 41* 44 42.5 41 42 40.4 39 48 45.9 44 55 52.2 48 58 55.2 52 7 44 ---- 43* 41 43.2 43 43 41.4 40 46 45.2 44 55 52.6 49 59 56.4 54 8 43 41.9 41 44 43.4 43 44 42.6 42 46 44.4 43 56 53.5 50 59 56.8 54 9 43 41.7 41 44 43.1 . 42 47 43.8 42 45 43.3 41 55 52.5 51 60 57.6 55

10 44 42.9 42 44 43.3 42 47 45~4 43 46 44 .. 6 42 54 51.8 49 61 58.3 55 11 43 42.2 41 46 44.8 43 48 45.5 44 48 46.3 45 51 50.2 48 62 59.5 57 12 43 41.9 41 45 43.7 42 47 45.9 45 48 45.6 43 51 ---- 48* 62 59.8 57 13 45 44.0 43 45 44.4 43 48 45.6 44 48 45 . 6 43 50 --- 46* 61 59.0 57 14 45 44.2 44 44 42.8 ~2 45 44.6 44 50 46.9 44 51 ---- 47* 60 57.6 55 t-J 15 44 42.4 42 42 41.2 39 45 44.1 43 52 49.4 47 53 50.8 48 61 58.0 55 ,.,.

16 42 41.1 40 43 41.4 40 43 40.7 37 52 50.7 48 54 so.o 46 63 59.5 56 17 40 38.8 38 44 43.2 42 39 37.1 36 51 49 .. 8 47 50 48.4 47 65 61.3 57 18 41 39.1 38 43 42~1 40 43 39.9 38 52· 49.5 46 50 48.3 46 67 63.4 59 .

19 40 ·39.6 38 42 40~4 38 41 40.8 40 52 49.5 46 51 48.6 46 68 65.1 61

·.•.'' 20 39 37.7 36 42 40.5 39 40 39.8 39 52 49.2 45 53 50.7 48 69 65.6 62 21 37 35.5 35 43 40.9 39 45 41.0 38 50 47.9 44 54 51.7 49 69 66.0 63 22 37 35.0 34 44 42.4 41 44 41.7 38 50 47.6 44 53 52.4 51 67 65.2 63 23 37 35.0 34 42 41.4 40 44 40.6 38 51 48.1 45 52 50.7 48 69 66.1 62 24 37 35.3 34 42 40~7 39 44 42.2 41 50 49.0 47 52 so.s 49 66 65.3 64

25 38 36.6 36 42 40.3 39 43 41.2 39 49 45.7 43 52 50.8 49 65 63.2 62 26 40 37.3 36 42 40.6 39 43 40.8 39 50 46.2 43 52 51.2 50 66 62.7 59 27 40 37.4 36 43 40.6 40 47 44.4 42 51 48.7 46 53 50.9 48 68 64.9 61 28 40 37.0 35 43 40.9 39 46 44.8 43 52 50.0 47 54 52 .. 1 50 69 64 . 8 60

' . ~ 29 42 39.1 37 48 46.0 43 53 50.1 47 53 51.6 50 70 66.0 61 30 41 40.6 40 48 __ 46.3 - 44 . 54 . 50.9 47 53 52.6 52 70 66.3 61 31 40 39.7 39 .·' 48 46.6 44 58 54.1 51 Av. 41 . 39.8 39 43 41.9 41 44 42.5 41 49 46.8 44 53 50.7 48 63 60.4 58

*Readings taken with hand thennometer. ...._ ,_

._., t . ' -...../

TABLE NO. 4 (Conoluded)

1945 DAILY RIVER TEMPERATURE, TRINITY RIVER AT LEWISTON

July August September October November December

· . .. .. ~ Day Max. Av. Min. Ma.x. Av .• Min. Max. Av. Min. Max. Av. Min. Ma.x. Av. Min. Max. Av. Min.

1 72 67.8 62 81 73.8 68 76 70.8 65 67 61.8 56 51 49.9 49 43 43.3 43 2 74 69.6 64 80 73.5 67 76 70.7 64 66 61.5 55 52 50.9 50 45 44.2 43 .. 3 75 70.5 66 80 73,3 67 75 69.6 63 64 60.4 56 52 51.1 50 44 43.6 42 4 75 70.6 66 81 73.6 66 76 70.t 63 63 59,7 55 53 51.3 50 ~2 40.5 39 5 76 71.3 66 81 74.6 68 76 71.1 66 65 60.8 55 52 50.2 48 43 42.2 41 6 76 71.8 67 81 75.4 71 74 69.3 64 67 62.3 57 48 46.6 44 44 43.3 42 7 77 72.6 68 80 73.9 68 75 68.7 62 68 63.7 58 48 45.2 41 43 42,8 42 8 78 73.3 69 81 73.8 67 75 69.4 63 68 65.0 61 48 45.6 44 42 41.8 41 9 73 71.0 69 82 74.9 68 76 70.0 63 67 64.5 62 46 44.8 44 41 40.5 40

10 73 69.6 67 81 75.2 70 77 71.1 64 69 65.5 62 47 45.1 44 42 41.1 40 11 76 71.3 66 81 74.3 68 78 72.3 66 69 65.7 63 46 45.2 44 42 41.1 40 12 78 73.2 69 79 73.0 67 78 72.3 66 69 65.3. 62 46 44.9 43 40 39.3 37 13 79 73.9 69 79 . 71.8 65 78 72.6 67 69 64.3 61 48 46.0 44 38 36.3 35 14 79 73.7 70 78 72.0 65 77 71.4 65 68 63.3 59 45 44.7 44 36 35.2 34

...... 15 79 73.4 68 79 72.3 66 75 70.3 64 65 62.3 58 45 43.9 43 37 36.5 35

· .. ,., ~., 16 79 73.7 69 79 72.3 66 73 68.7 63 65 62.3 60 43 42.5 41 40 38.5 37

17 81 73. 4 68 80 73.3 66 73 68.1 . 62 67 62.6 59 44 42.6 41 40 39.2 38 18 79 73.0 68 75 71.9 69 73 68.7 63 66 61.5 58 45 44,6 43 39 38.3 38

:~. 19 79 71.8 66 79 72.6 67 73 67,9 62 65 60.6 57 46 45.3 44 39 37.7 37 -20 80 71.3 64 80 73.7 67 68 - 65.3 61 65 61.0 58 46 45.2 44 39 37.8 37 21 80 71.8 64 80 73.9 67 66 62.7 59 60 57.2 55 45 44.0 43 39 38.8 38 22 -- ---- -- 80 73.7 67 68 62,6 58 58 55.5 53 45 44.2 43 41 39.,7 39 23 80 75.3 70 79 72.8 67 67 61.7 56 58 53.9 50 46 45.3 44 42 41 , 0 40 24 81 74.8 70 76 70.7 66 6.8 62.5 56 57 52.8 48 45 45.1 44 42 12.0 42 25 81 74.4 69 74 69.1 63 68 62.8 57 57 52.4 48 43 43.0 42 43 42.5 12 26 82 74.4 69 75 69.5 63 66 61;6 56 56 52.4 48 45 43.8 43 43 42.3 12 27 83 76.4 70 75 69.8 64 / 65 60.3 55 54 52.7 51 45 45.3 44 44 ---- 42* 28 82 76.2 71 74 69.3 64 66 60.6 54 53 52.7 52 45 44.4 43 44~ ----- 43* 29 --81 75.2 70 74 69,8 65 66 62.1 55 53 51.0 49 44 43.3 42 43 ----- 42* 30 80 73.8 68 77 70.4 64 67 61.5 55 -- ---- -- 44 43.3 42 43 ---- 42* 31 80 73.7 68 76 70.6 64 -- ---- -- 50 19.5 49 -- ---- -- 43 ---- 42* Av. 78 72.9 68 79 72.5 67 72 66.8 61 63 59.4 56 47 45.4 44 42 40<. 7 10

*Readings taken with hand thermometer.

• \\o .,_ .... -

TABLE NO. 5

1946 DAILY RIVER TEMPERATURE. TRINITY RIVER' AT LEWISTON

Januarl* Februa!::i: Maroh AEril Mal June Ju1l August Dal Max. Min. Max. Ave. Min. Max .. Ave. Min. Max. Ave. Min. :Max. Ave. Min. Y..ax. Ave. Min. Max. Ave. Min. Max. Ave. Min.

., 1 44 43 43 42.0 41 47 45.0 43 51 47.8 44 58 55.5 52 70 65.3 61 77 71.3 66 2 44 43 43 41.8 40 46 45.2 43 53 49.5 45 58 . 56.1 53 70 65.9 62 79 73.3 68 3 43 43 42 40.9 39 46 45.5 44 52 49.4 45 58 55.8 53 71 66.3 62 80 73.7 70

- t 4 39 39 43 41.2 38 48 45.7 43 51 48.5 44 58 55.7 53 72 . 67~1 63 79 73.2 69 5 42 41 44 42.5 41 49 47.0 45 51 47.9 44 57 55.3 53 72 69.4 67 78 71.8 67

·-. 6 40 40 46 44.1 42 50 47.9 46 52 48.7 44 55 55.3 50 72 67/7 63 77 70.8 66 ·. "' .. ~ ·.

7 40 39 45 44.0 41 49 47.6 47 51 48.6 45 57 54.6 51 72 67.4 63 78 71.0 66 8 40 39 <16 44.5 42 47 45.7 44 51 47.9 14 58 55.7 53 69 66.1 63 79 71.5 56 9 39 38 39 36.8 35 45 43.9 41 48 45.8 44 52 48.8 45 58 56.0 54 72 66.9 62 79 71.8 66

10 40 39 38 36.5 35 45 43.6 42 49 46.7 44 53 19.8 46 59 56.1 54 72 67.9 63 I

11 -- 39 38 35.5 34 44 42.8 40 50 48.8 46 52 '19.0 44 60 57.4 54 74 69.2 65 12 37 36 37 35.2 34 44 43.6 43 50 49.3 48 53 50.2 46 61 58.0 55 74 69.8 65 13 38 36 38 35.7 34 45 43.3 41 52 19.7 47 52 50.2 47 59 57.3 56 73 69~3 65

..... 14 39- 37 38 36.3 35 43 41.5 39 51 49.2 46 . 52 49.7 46 59 56.8 54 70 67.2 65 m 15 38 37 39 37.6 36 45 43.0 41 52 49.5 46 54 51.3 48 58 56.5 55 72 66.3 61

16 39 38 10 38.4 37 45 43.3 41 52 49.4 45 55 51.6 48 61 57.9 55 73 67.7 63 17 38 37 41 39.3 38 45 44.2 43 52 48.7 44 56 •51.5 48 63, 59.3 57 74 68.9 64 18 -- 38 42 40.2 38 43 42.2 41 50 47.2 44 55 52.7 49 64 60.4: 5? 76 70.3 65 19 40 38.9 38 43 42.9 42 49 46.8 44 55 52.0 48 65 61.7 53 78 71.9 67 20 40 38.9 38 45 43.7 42 49 46.3 43 54 51.8 49 66 62.8 54 79 73.2 69 . 21 41 40.0 39 47 44.8 43 49 46.7 43 48 47.7 46 65 62.7 60 79 73e7 69

·•· . ....., 22 43 40.8 39 46 45.8 45 51 47.8 44 47 46.7 46 64 61.5 59 80 75.0 71 23 42 41.2 40 45 43.0 42 52 49.3 45 49 47.6" 45 62 59.5 57 79 74.8 72 24 42 41.2 40 47 44.1 41 52 49.0 44 50 49.2 47 63 59.0 55 78 73.5 70 25 43 41.3 40 47 45.8 43 . . 51 48.4 44 50 49.6 48 65 60.8 51 '12 69.5 67

" 26 41 40.4 39 49 47.5 45 50 47.0 43 53 49.3 49 65 61.5 58 67 66.0 64 .. .. f,V. 27 44 42.2 41 48 46.9 45 51 47.5 43 54 50.5 47 64 61.5 58 73 68.0 63

28 43 41.8 40 47 44.1 42 51 48.2 44 54 52.2 49 61 60.6 58 75 70. 3 66 29 42 40.1 39 50 47.6 45 54 52.2 49 55 60.6 56 75 70.3 66 30 42 41,2 39 49 45,8 4.2 54 52.7 49 68 63.5 59 73 69.0 66

,.;. -~ 31 44 43.2 42 58 55.0 52 75 69 .. 2 64 Ave. ~ V ~1 40 39 :0 38 45

- -~-- ,.--- 43.4 42 50 -47.2 45 53 49.7 47 61 J 58.2 55 74 69A 65 78 72.8 67 *Readings taken with hand thermometer. -

.·t:" • ... 1 4>

TABlE NO. 6

1945 DAILY RIVER TEMFERATURE, TRINITY RIVER AT JUNCTION CITY

July August September October November December

~ li.ax. Av. Min. Max. Av. Min. Max. Av. Min. Max. Av. Min. Max. Av. Min. M.a.x. Av. Min.

•. - .o; 1 -- ---- 83 77.3 72 76 72.8 67 69 63.4 58 51 49.6 48 ,·44 43.6 43 --

2 -- ---- -- 80 76.1 71 78 72.7 67 68 63.1 58 53 51.3 49 44 -t3.5 42 3 76 ---- -- 82 75.8 70 77 71.8 66 66 62.2 59 54 53.0 52 44 43.6 43

4 76 72.6 68 81 75.7 70 77 71.6 66 66 61.8 58 54 52.6 51 43 42.4 41 5 77 . 73.3 69 81 76.0 70 77 72.0 68 67 62.0 57 53 51.5 49 44 42.9 41 6 77 73~8 70 81 76.5 72 76 70.7 66 66 62.5 59 50 48.7 46 45 44.2 43 7 79 75.0 n 80 75.0 70 76 70.0 64 68 63.9 59 48 46.4 45 44 43.3 42 8 79 75.4 72 81 75.3 69 77 71.2 65 68 65.4 62 48 46.8 45 43 n.8 41 9 74 72.6 72 82 76.2 70 77 71.7 66 67 65.0 63 47 46.9 46 41 40.7 40

10 74 71.2 69 80 76.2 72 79 72.6 67 69 65.4 62 47 46.,4 45 42 41.4 40 11 78 73.5 70 80 75.1 70 80 73.6 68 69 66.1 63 46 45.5 44 43 41.9 41 12 79 75 .. 0 71 79 74.3 69 79 73.6 68 70 66.1 63 48 46.1 45 41 40.2 38 13 80 75.8 72 80 74.2 68 79 73.4 69 70 65.5 63 49 46.6 45 39 37.5 36 14 80 76.0 72 50 74.2 69 78 72.2 67 69 64.5 61 47 46.1 45 36 35.7 34 15 80 76.0 72 eo 74.4 69 76 71.3 67 68 63.7 60 47 45.7 45 37 36.2 35

.... 16 80 75.6 72 79 74.0 68 75 70.4 66 65 63.0 61 45 44.2 44 38 37.7 37

17 79 75.2 71 81 75.3 69 76 70.0 65 67 63.0 61 45 43.9 43 40 38.9 38 18 80 75.3 71 75 73.5 71 76 70.5 66 67 62.2 59 45 44.4 43 40 38.8 38 19 78 74.1 70 79 73o8 69 75 69.7 65 66 61.7 58 47 46.1 45 39 38.0 37 20 78 73.6 69 eo 74.6 69 71 67.1 64 66 61.8 59 47 46.0 45 38 38.1 38 21 78 73.6 69 81 75.3 70 66 63.8 61 60 58.,4 56 46 45.1 44 40 39.3 38 22 79 74.3 70 81 75.3 70 69 63.8 60 60 56.5 53 46 45.2 44 40 40.0 40 23 80 75.0 70 79 74.0 69 68 63.4 59 58 54.4 51 47 46.5 45 41 40.5 40

24 BO 75.3 71 76 72.0 68 70 64.2 59 58 53.,5 50 47 46.1 45 42 41.8 41

25 81 75.4 70 76 70.8 66. _ ... 70 - 64.8 60 57 53.0 49 45 43.6 43 43 42.4 42 26 83 76 . 7 71 76 '11.0 66 69 64.1 59 56 52.5 49 45 44.0 43 42 42.3 42 27 85 78.5 73 76 71.4 66 66 62.1 58 53 52.2 51 46 45.4 44 44 ~2.7 42 28 84 78.9 74 75 71.0 66 67 61.4 56 53 52.2 51 46 45.2 44 46 44.8 -. 44 29 82 77.6 73 77 71.5 67 68 62.,5 57 53 52.5 52 44 43.5 42 45 44.3 44 30 82 76.3 70 78 72.3 67 68 63.0 58 52 49.5 48 45 43o7 43 44 43.4 43 31 82 77.1 71 78 72.7 67 -- ---- -- 49 49.5 48 -- ---- -- 44 43.5 43

Averages 79 75.1 71 79 74.1 69 74 68.9 64 63 so.o 57 48 46.4 45 42 41.0 40

1.\. ....... - • • ~ ·-~--- • •

TABLE NO. 7

• 1946 DAILY RIVER TEM.FERATURE, TRINITY RIVER AT JUNCTION CITY

January Februa;sy: Mal June Ju1l Day Max. Av. Min. Max. Av. Min. Max. Av. Min. Max. Av. Min. :Max. Av. Min.

1 45 43.3 44 38 37.7 36 -- ---- -- 61 57.9 54 71 67.6 64 2 44 44.0 44 39 38.7 38 -- ---- -- 62 59.4 57 71 67.9 64 3 43 43.2 43 39 38.4 37 -- ---- -- 62 59.0 56 71 68.1 ' 64 4 43 41.5 40 38 37.7 36 -- ---- -- 62 59.2 56 72 69.3 65 5 43 41.6 41 38 37.7 37 -- ---- -- 61 58.4 56 73 69.6•'· 66 6 42 41.3 41 38 36.0 35 -- ---- -- 61 57.9 54 73 69.8 66 7 41 40.6 40 37 35.6 34 -- ---- -- 62 57.9 54 73 69.8 66 8 41 40.2 39 39 37.3 35 -- ---- -- 62 58.9 55 70 68.5 66 9 40 39.4 39 40 39.0 38 -- ---- -- 62 59.2 56 73 69.4 65

10 41 39.5 41 39 38.0 37 -- ---- -- 62 59.2 55 74 70.6 67 11 41 39.8 39 39 37.5 36 -- ---- -- 64 60.7 57 75 71.7 68 12 39 37.8 36 38 37.1 36 -- ---- -- 65 61.8 58 76 72.3 68 13 38 37.2 36 39 37.6 36 -- ---- -- 63 61.3 58 14 39 36.8 36 38 37.8 36 -- ---- -- 63 60.5 57

.... 15 39 37.9 36 39 38.8 38 -- ---- -- 62 60.0 57

CD 16 39 38.0 37 -- ---- -- -- ---- -- 64 60.7 57

17 39 38.0 37 -- ---- -- -- ---- -- 66 62.6 58 . 18 39 38.0 36 -- ---- -- -- 67 63.S 60 -- ---- ..... 19 38 37.8 37 -- ---- -- -- ---- -- 69 65.3 61

20 39 38.8 37 -- ---- -- -- ---- -- 70 66.6 62 21 39 38.8 38 -- ---- -- -- ---- -- 69 66.9 63 22 40 39.5 39 -- ---- -- -- ---- -- 66 64.3 62 23 42 40.8 40 45 44.4 43 -- ---- -- 64 61.3 58 24 42 41.4 41 43 42.4 41 -- ---- -- 64 61.3 58 25 42 40.7 40 44 42.2 40 51 50.2 49 66 62.8 59 26 40 37.9 38 42 40.6 39 52 49.9 48 66 63.2 60 27 38 36.8 35 -- ---- -- 54 51.2 48 55 63.6 60 28 38 37.1 35 -- ----- -- 56 --------- 52.6 49 64 62.2 61 76 72.2 69 29 39 37.0 35 -- ---- -- 57 53.4 50 66 62.5 58 76 72.2 69 30 38 37.4 36 -- ---- -- 57 54.2 51 69 65.8 62 74 71.1 69, :n 38 37 . 1 35 -- ---- -- 58 55 .6 52 -- ---- -- 76 71.7 67~

Averages 40 39.3 38 40 38,7 37 55 52.4 50 65 61.5 58 74 70.1 67

\_ • I ina.otivo during the daytime when they rest in shallow water or in rubble on the river bottom, but they start feeding at sunset and remain active until the next morning. There seems to be no gregarious tendency during this aotive period. Observations of feeding activity indicate that dace are omnivorous. Most feeding takes place on the algal~covered bottom, but drifting rood particles and floating insects are also taken. In winter months, dace are seldom seen in the open, although their appearance in fyke-net oatches during this period indicates some nocturnal activity.

The Klamath black dace or Trinity River have been extensively re~ ported on by Jhingran (1948). Muoh of the dace material collected during this investigation was placed at his disposa l and is incorporated in hie study.

Fine~scaled Kl,amath River suckers are as lrldely distributed in the river a are the dace, but the y are much less abundant. They are most commonly found in deeper holes along the river and in tributaries with moderate gradients. It is common to see l arge schools feeding along the bottom of pool areas any time or the year . This fish apparently has little value in the 'l'rini ty River o..a a forage f'i h f'or large trout.

Undoubtedly, juveniles enter the diet of native trout and steelhead, but most small suckers are found in tributary strewna where large trout do not occur.

Resident Game Fishes

The . Trinity River inve~tigation has revealed the presence or three resident Salmonidae: rainbow trout, Salmo gairdnerii (Richardson) J brown trout, Salmo trutta (Linnaeus) J and eastern brook trout, Salvelinus fontinalis (Yi tohill) J named in order of abundance.

Rainbow trout, the only native species, are distributed in fairly large numbers throughout the drainage, except in the upper extremities of some tributaries. This species contributes the major portion of all game fish taken by spqrtamen. The california Division of Fish and Game reporta that approximately 7,750 anglers took an eotimated 389,900 trout from the Trinity River in 1941. No observatione haves been made of rainbow trout spawning activities, but ripe males have been taken during the steelhead spawning period (February - April) in Ruoh Creek, a tributary• and it ms.y be assumed that they spawn during that period.

Brown trout are also generally distributed but are fewer in number and more oonspiouously absent from the upper extremities or the river and i tB tributaries than are the rainbow. There are kncnm to be definite spawning migrations of adult brown trout in the Trinity. From

:· . . • t l 'l

I I j I I •

June 29 through August 2. 1945, 39 brown trout passed through the gates of the Lewiston fish-counting weir. Six specimena taken for study had an avere.go eight of 5. 7 pounds and an average length of 23.4 inches • Their sex products were further developed than those of steelhead, but less than salmon taken at the same time. Less conspicuous but larger migration£ occur during November and December. Although these fish have not been observed spawning in the Trinity River during this study, local residents report having seen them spawning in the upper main stream and its tributaries from late December until early February.

Several young brown trout were usually taken in the fyke nets at Lewiston during the week following the first fall rain.· A f~ young, near or in their second year, were taken through the remainder of the winter months. Fry of this species, that had recently left the gravel, were taken by fyke nots o~ ve~ rare occasions in March and April. It is possible that the brawn trout of Trinity River migrate to the sea as do representatives of the same species in Europe, although no direct evidence is yet available to demonstrate such movement. Scales from the specimens taken at Lewiston were so resorbed that positive age and growth determi nation8 oould not be made.

Rather lind ted populations of eastern brook trout ooour in the oolder wa. ters of the upper e:xtremi ties of the Trinity River and its tributaries. They are caught in fair numbers by sportsmen who frequent the higher, primitive areas o These fish do not attain a ve11• large size in the drainage, but their gaminess and limited distribution make them highly desirable to many sportsmen.

Anadromous Fishes

Four anadromous or sea-run fishes have been recognized in the Trinity River during the course of this investigation. These are the three-toothed lamprey, Entosphenus tridentatua (Gai rdner)J the king salmon, Oncorhynchus tsoh.a.wytsoha (Walbaum) J the silver salmon, Onoorhynohus kisutch { albaum) J and the steelhead trout, Salmo gairdnerii (Richardson).

King salmon

Commercial and sports fisheries

King salmon have long been sought by Indians, commercial fisher· men, and sportsmen as one of the moat abundant artd desirable of the Pa.cifi o salmons. The part played by the Trinity River in supplying the salmon fishery of california is not definitely known, but some

_ _:•:....c-~-----· idea of its contribution oan be deduced from discussion of catch statistics. An average annual oatoh of 2,286, 588 pounds of salmon .

has been taken commercially from waters of Humboldt and Del Nor~ 1

Counties over a period of 28 years (Tab l e 8). These counties He / north and south of the mouth ~f the Klamath Rive1·, and catches ~here certainly include a major portion of the contribution of the Klamath River. Salmon or iginating from other drainages appearing in these catches are assumed to be compensated for by Klamath River salmon taken north and south of these two counties. Trinity River con stitutes approximately one-third of the total Klamath drainage accessible to spawning salmon, and its contribut ion to the oom meroial fishery supported by the Klamath drainage is assumed to be proportional to its part of the drainage area involved. Based on these assumptions, the annual oatoh of salmon from Trinity River ould approximate 762,200 pounds.

An important sports fishery materially increases the value of the salmon production. It is difficult to even approximate the valne of these fish to the sportsmen. Businesses and people benefiting from sport fishing are so greatly varied and widely distributed that a summation of values is impossible. The california Division of Fish and Game estimates that 1,385 anglers took 11, 496 salmon from the Trinity River in 1941. Based on an average weight of 11 pounds per salmon, this oatch amounted to 126,456 pounds. The total production of the salmon fishery resource of the Trinity River is probably 890,000 pounds per year.

Charaoteristios or the seasonal runs \

King salmon enter the Klamath River from the ocean in two well defined runs, one in spring and another in fall. The spring run, onoe the largest run entering the river, begins in late Maroh, reaches a peak in May, and diminishes to the vanishing point by the end of Jtme. At present, this run is very small, but Snyder (1931) cites a paper by R. D. Hume (undated) as authority for the assertion that in 1850 and even later the spring run was the most abundant. It was practically extinct in 1892, and no evidence of recovery ~s evident when Hume wrote his article which certainly appeared before the turn of the cen tury. The summer run usually begins to enter Klamath estuary about the first of July. It increases gradually throughout that month, reaches a peak in August, declines steadily through Se ptember, and practically disappears by the beginning or winter. There appears to be little or no segregation of this latter run into summer and fall segments.

Adult king salmon migrate- past Lewiston enroute to their a~wning grounds in what appear to be three seasonal groupsr…