INJURED AND DEAD FISH IN THE VICINITY OF BONNEVILLE DAM Marine Biological L^bjuiu. I. I B K. .A. :« "Y NOV 151850 WOODS HOLE, MASS. SPECIAL SCIENTIFIC REPORT: FISHERIES No.29 UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE Explanatory Note The series embodies results of investigations, usually of restricted scopcj intended to aid or direct management or utilization practices and as guides for administrative or legislative actiono It is issued in limited quantities for the official use of Federal, State or cooperating agencies and in processed form for economy and to avoid delay in publicationo V/ashington, Do Co Jtino 1950 United States Department of the Interior Oscar L« Chapman, Secretary Fish and Wildlife Service Albert M. Day, Director Special Scientific Report - Fisheries No. 29 INJURED AND DEAD FISH IN THE VICINITT OF BONNEVILLE DAM By Harry A. Hanson, formerly Aquatic Biologist, Fish and Wildlife Service, Paul D« Zimmer, Fishery Research Biologist, Fish and Wildlife Service, and Ivan J. Donaldson, Biologist, Corps of Engineers, U. S. Army CONTENTS Page Introduction •• ••• •..••....• 1 Section !••• • 2 Injured Fish Studies. .• 2 Injuries observed at Bonneville Dam 2 Injuries, 1943 2 Net injuries, Chinook Salmon, 1946 2 Injuries observed above and below Bonneville Dam ... 2 Big White Salmon Hatchery 3 Bonneville Hatchery. ................. 4 Observations of fish passing through submerged openings in Bonneville fish ladder ...• 7 Section II ...'12 Adult fish mortality studies - 1946 -12 Float experiment ••••• 12 Observations of dead fish. 16 Dead fish below Bonneville 16 Dead fish above Bonneville ........••.••. 19 Dead fish used by sturgeon fishermen 22 SusTvoiary. •...'.22 Conclusions ........24 Appendix Table 1, River flow in cubic feet per second -Bonneville Dam August 1 - September 15, 1946 • ' 25 Append ix Con t • d » Table 2, Bonneville count-ohinook, steelhead, blueba;k, and silver salmon for years and months during which dead fish observations were conduotedo o Page i.O Table 3, Dead salmon and steelhead trout fo-jnd between Bonneville Dam and Multnomah Falls, 1938=194:6. o o 2.'" Table 4, Record of dead fish found Columbia River Bonneville Dam - Multnomah Falls, August - September, 1938o o ?,d Table 5, Record of dead fish found Columbia River Bonneville Dam - Multnomah Falls, July = October, 1940. . o o £8 Table 6, Record of dead fish found Columbia River Bonneville Dam - Multnomah Falls, April = October, 1941 o <> o e 25? Table 7, Record of Dead Fish Found Columbia Rive:.." Bonneville Dam - Multnomah Falls, June •= September, 1942o o o Table 8, Record of dead fish found Columbia River Bonneville Dam " Multnomah Falls, June = October, 1943o coo m Table 9, Record of dead fish found Columbia River Bonneville Dam - Multnomah Falls, May - Septembe:-, 1944 e c o 31 Table 10, Record of dead fish found Columbia River Bonneville Dam - Multnomah Falls, July - September. 1945o » o 22, Table 11, Record of dead fish found Columbia River Bonneville Dam - Multnomah Falls, April - O^^tober, 1946 « • o 32 Appendix I « S'ommary. . . • Appendix II. Introduction Me t ADds o . • Observations Summaryo . • 3", 33 ST •&0 ILLUSTR/.TIONS FIGURE PAGE le Chir.sok Sairaon with dorsal and ventral fin injuries observed at Big White Salmon Hatchery «<>ooo>.*«5 2, Chinook Salmon with dorsal and ventral fin injuries plus the completely encircling abrasions observed at Big White Salmon Hatchery. •oe<>ooooo<..»»6 3o Chinook Salmon with dorsal fin injuries obscrvsd at Bonneville Hatcheryo oeooo»oooooo...»3 4o Ctiinook Salmon with ventral fin injuries and completely anciroling abrasions observed at Bonneville Hatcheryo • 9 5o Su'bm'rfrsible chamber built by U. S. Corps of Engineers to observe fish movement in the Bonneville fish ladder oil So Wooden float used in experiment to detennine direction and influence of wind drift below Bonneville Damo o o «13 7o Position of wooden float in water* oo.oo.oooo ol4 &o Location and numbers of dead fish found between Bonneville Dam and Cape Horno 1946 « ooooocooo o20 9o Loc*!.tion and numbers of dead fish found between The Dalles and Bonneville Damo 1946 .<><>.<.<> oo . .21 INTRODUCTION The following report is the result of a study made jointly by the Fish and Wildlife Service and the War Department, Corps of Engineers to determine (l) the mortality of adult fish above and below Bonneville Dam, and (2) the extent of visible injuries to adxilt fall chinook salmon at Big White Salmon Hatchery above the dam and at Bonneville Hatchery just below the dam, Bonneville Dam and related facilities were constructed by the Corps of Engineers, for improvement of navigation and the development of hydroelectric power. It was built across the Columbia River about 140 miles upstream from its mouth and about 40 miles east of the City of Portland. On the following pages will be found the summary and conclusions of the investigators on the studies conducted. A description of the problem, the methods of investigation, and the data collected during the study are presented in Sections I and II, Section III is an appendix showing tables of pertinent data and maps illustrating the areas and ori- enting the studies in the preceding sections. The investigation was under the general supervision of J, T. Barnaby, In Charge, North Pacific Fishery Investigations, Fish and Wildlife Servicei Harry A, Hanson of the Service directed the work in the field. He was assisted by Paul D, Zimmer, Russell L, Bagwell, Eugene M. Maltzeff and Curtis P. Jensen of the Service, and Ivan J. Donaldson of the Corps of Engineers. Other members of the Corps of Engineers and local residents contributed information and services which measurably facilitate.d the progress of the investigation. Personnel of the Columbia River Packers Association stationed at Ellsworth cannery graciously made available their dock and moorage facilities for operations at that point. With the building of Bonneville Dam several problems arose concerning the runs of anadromous fishes in the Columbia River and its tributaries. The first problem was to provide safe passage for adult fish on their journejr upstream to spawn. This was accomplished by building an elaborate collection system, together vrith fish ladders and fish locks which enable the fish to swim up around the dam or to be "looked" through the locks. Secondly, and of equal importance, was the installation of fish screens and bypass channels to facilitate the downstream movement of the seaward mi grants . Since the earliest mention of plans for a dam at Bonneville, there has been considerable speculation about its effect on salmon, steelhead, and other fish. Soon after completion of the dam and its component parts, many commercial fishermen and anglers reported seeing dead salmon and other fishes floating dovmstream below the dam at f^arious times of the year. The Corps of 'Fngineers accordingly instructed its biologists to make periodic trips dovmstream in a boat to learn the extent of mortality, and if possible, to determine if the fishes died as a result of injuries received at Bonneville Damo These studies have been carried on for the past eight years (Appendix, Table 3) o Data obtained during the fall migration period in September 1946 by the U. S. Fish and Yfildlife Service in cooperation with the Corps of Engineers are included in the text. SECTION I INJURED FISH STimiES Injuries Observed at Bonne-vllle Dam« For several years, it has been the practice for the fish counters at Bonneville Dam to keep a record of the number of injured fish observed. Prior to 1941 they had recorded merely that there was an apparent injury on the fish, and then only those injuries deemed "Serious'* were recorded. In May 1943, during the height of the spring rim of saMon,, a more detailed record was kept, showing not only the number of injuries but also the type and location of each injuryo Injuries, 1943. In a sample of 37.805 chinook salmon passing up the ladders during May of 1943, 339 shov/ed injuries. Of this nuniber, 165 or about 49 percent were injuries to the dorsal fin, and the remaining 174 were injuries to other parts of the body of the fish. l^et Injuries, Chinook Salmon, 1946. In the STimner of 1946^ a series of SBmple counts wps made at counting stations in the fish ladders at Bonneville Dam to determine the frequency of net marks and other injuries. Injuries other than those obviously caused by nets were wounds and abrasions on various parts of the body of the fish. In some cases, there were deep gouges on the flesh along sides and peduncle area. In others, large torn patches of skin were hanging loose,, leaving the muscle tissue exposed j and in still others, fungus patches had begun to form ou previous cuts or abrasions on the snout and tail. The numbers of net and other injuries during June, July, and Aurust 1946 are shown in Table 1. Injuries Observed Above and Below Bonneville Dam. In order to determine whether there were more injured fish above Bonneville Dam than belOTf and the types of injuries present at each locality, observers were stationed at Big White Salmon and at Bonneville Hatchei^ie; during the height of spawning activities. Pig White Salmon Ititchery is on the Washington Shore approximately 30 miles above the dam, and Bonneville Hatchery is approximately one mile below the dam on the Oregon shore. At each hatchery the observers daily recorded the following data for Chinook salmon: (a) total n-jmber of fish examined, (b) dorsal and ventral fin cuts or abrasions, (c) completely encircling abrasions, and (d) other injuries. Table 1. Nxjmbor of bluebaok and chinook salmon and steelhead trout counted, number of fish in various samples taken, and number of injured fish observed in each sample at Bonneville Dam during June, July, and August 1946. s Total Date ; count , A* "Number : in ssample Number w/ encircling abrasions B X Percent C* Number in sample Number w/ ; D other i "C injuries jPercent 1946 STEELHRA.D TROUT June 3,265 1,466 July 2Q,559 11,782 August 58,356 46,747 June 7,805 3,290 64,704 46,605 August 1,746 797 July June 30,051 24,099 July 20,960 13,042 August 45,421 28,403 72 4.9 378 3.2 10,097 3,157 6.7 48,687 BLIIEBACK SAD-ION 71 2.2 1,902 4.0 41,411 54 6.8 836 CHINOOK SAMON 1,02 3 718 2,463 4.2 16,604 5.5 17,808 8.7 27,028 197 594 478 38 973 ,545 978 1,9 1.2 1.1 4.6 5.9 8.7 3.6 ♦These numbers represent the sum of the samples counted each day. The study at the two hatcheries was concerned with fall-riin fish which did live until spawning time in the hatcheries j therefore, injuries such as cut or mutilated dorsals and ventrals and encircling abrasions did not cause the premature death of these fish. Such injuries to spring- run fish that must remain several months longer in waters of the upper tributaries before reaching sexual maturity might cause a high mortality because of fungus or other infections. Big White Salmon Hatchery. At this hatchery, salmon ascend a small fish ladder, enter a long concrete pool, and remain several days to com- plete development of their eggs and sperm. From here the males and females are sorted and placed in separate holding areas in an adjacent pool. There are no nets used in these operations, and consequently observers believed it impossible for the fish to get dorsal or ventral fin injuries or en- circling abrasions in either the fish ladder or the hatchery pools. The number of fish examined at the Big White Salmon Hatchery and the number of injured fish obeerved are presented in Table 2. Table 2, 'Nr-ara'her of chinook salmon examined at the Big VVhite SalTion Hatchfry (apprcxirsately 30 miles above Bonneville Dam) and mmber of injured fish ob??erved* during the pioiod September 24-October 4, 1946. Total Dorsal fin Ventral fin Enoir cling Date examined ubrasicns abrasions abrasions ITo . ITo. Percent Mo. Percent No. Percer.-': 9/24/46 547 r53 29.1 120 21. D 35 sTi 9/26/46 1,207 264 21.8 200 16.6 50 4.1 10/4/46 409 76 18.6 74 1^.1 17 4.2 Totals 2,163 499 23.0 394 18.2 102 4.7 * In addition to the injuries noted in the table, 37 fish or 1.7 percrnt had open b odj'' wounds . Of the 499 fish with dorsal-fin injuries, 78.9 perocnt had the accompanying ventral-fin injuries. All of the fish with encircling abra- sions had both dorsal and ventral cuts. It is apparent in Figures 1 and 2 that these injuries v/ere caused by nets. Out of the total sample of 2,163 fish examined, 37 or 1.7 percent had open body wounds. Two fish had open cuts in the peduncle area. The other 35 fish had cuts just bade of the head or crescent-shaped wounds on the underside bet'/zeen the pectoral fins. No explanation is available of the source of these injuries. Bonneville Hfatchery. Tanner Creek, v/hich flows through the hatchery holding ponds, enipties Tn"'.::- the Coluribia River about a mile b-:low Bonne-vrille Dam. As the fish enter Tanner Creek, most of them proceed upstream through the raceway and directly into the hatchery holding ponds. A portion of the later arrivals, hov/ever, remain in the raceway. The fish that have entered the holding ponds are collected for sorting by the use of a 3 l/2 inc-h stretched-^iesh seine. Kales are separated from females and placed in separate holding arens. At ths tine of spawning operations, these fish are again collected by seining. "fthen the time arrives to ocllect spawn from the fish that have remained in the racev/ay, the flow of vj-ater is decreesed to permit sein- ing. Again the 3 l/2 inch seine is used for collecting the fish. It was aonsicered impoosiblt for the fish to fiot dorsal, ventral, end encircling abrasion;: in the net used because of the small size of the mesh. On September 20, the observer at Bonneville Hatchery reoorded only dorsal-fin injuries, and it was found that these ocourred on 28.5 peroo:at of the 56 fish examined on that day. ?• 4 Figure 1. — Chinook Salmon v/ith dorsal and ventral fin injuries observed at Big- White Salmon HcLtchnry. Figure 2, — Chinook Salmon with dorsal and ventral fin injuries plus the completely encircling abrasions observed at Big Vfhite Salmon Hatchery. Table 3« TT'om'bor of chinook salmon examined at the Bonneville Hatchery (approximately one mile below Bonneville Dam) and riLimber of injured fish observed* during th.e period September 25-30, 1946o Dats Total examined Dorsal fin abrasions Ventral fin abrasions En- abr riircling No. No, . Perce nt No. Percent N-o Percent S/ 25/48 S/3C/45 162 35 233 46 18 70 28o4 27o7 24o7 38 12 61 23.4 18.5 21,5 1.V 00 X 10 « 7 3o5 Totals 510 134 26,9 111 19.6 22 3.9 * In addition tr the injuries noted in the table, 12 fish or 2.4 percent had open body woundK. It Hiay be pointed out that of the total of 510 f ieh examined on September 25 and September 30, 26.9 percent had dorsal-fin injuries (Figure 3), 19.5 percent had ventral<=fin injuries (Figure 4), and 3o? percent had well-defined encircling abrasions (Figure 4). Of the 134 fish with dorsal-fin abrasions, 82.8 percent had the acsompanying ventral-fin injury. All of the fish with encircling abra- tions had both dorsal=and ventral^fin injuries. Other injuries to fish observed at Bonneville Hatchery in the sample of 510 examined on September 25 and September 30 show&d 2.4 per= cent had open wounds about the body. Several of these fish had jres cent- shaped cuts on the underside of the body between the pectoral fins very similar to many of the injuries observed at Big White Salmon Hatchery, No explanation is available as to the cause of such injuries. In September 1945, Robert R. Rucker of the Service made observations of injured fish above and below Bonneville Dam. The following quotation is taken from his monthly report of activities. Complete text of hi.-s observations is given in the Appendix* ••On September 15, the gill-net oaught ohinook salmon from imriediately belov/ and above Bonneville Dam were examined. It was desired to determine whether or not the fish taken above the dajtri showed a greater percent with injuries on the dor-:ai fins. Of 170 chinook salmon taken below the Dam, 19^ showed an injury on the dorsal fins of 100 chinook salmon takeii above the Dam, 13^ showed an injury on the dorsal fin. These data indi- cate that the dorsal-fin injtiry is probably not incurred by the fish in the fishways at Bonneville Dam." Observations of Fish Passing Through Submerged Openj-ngs in Bonneville Fish Ladder© Preliminary to the study of salmon mortality of the Colorribia River in the vicinity of Bonneville Dam, a conference was held between personnel of the Fish and Wildlife Service and representatives of the Corps of Engineers at Bonneville. It was decided that it would be desirable Figure 3. — Chinook Salmon with dorsal fin injuries observed at Bonneville Hatchery. P'ip;ure 4. — Chinook Salmon with v entral fin injuries Rnd complrtely encirclinf, abrasions observred at Bonneville Hatchery. to observe the action of salmon in the Bonneville fish ladders as the fish passed through the submerged orifices in the weirs » Such obser- vations, it was believed, would determine whether or not the injuries observed at the counting stations and at the hatcheries could have been sustained in the ladders. Consequently, the Corps of Enpiaeers built a submersible operation chamber for the purpose (Figure 5)o The chamber was made of an 8-foot section of galvanized-iron culvert pipe, three feet in diameter. The lower end was welded to a steel plate, s/S inch thick and seven feet square. The pipe and its base were strengthened by having four steel-rod stays of 7/8 inch diameter fastened to the upper ring of the pipe and the plate bass to which it v/as welded. A 4 inch vertical flange was welded to each of the four sides of the base plate, forming an open box to hold the iron weights used in submerging the lower part of the chamber. About 3,200 pounds of cast-iron weights were necessary to overcome buoyancy. Two watertight glass observation ports were built into the walls of the chamber. One of the ports was 12 inches and the other 24 inches from the floor. The glass por^s were made of clear plate glass, 3/I6 of an inch thick and about 12 inches square. The device was provided with a cover to exclude light from above. On September 5, 1946, the observation chamber was lowered into the fish ladder in the first pool below the Bradford Island counting station, From the chamber, large numbers of chinook salmon and steelhead trout were observed passing through the submerged orifice m the lower weir of the pool. The velocity of the -water passing through the opening was about five feet per second. The following statement was taken from office memorancVjim of October 8, 1946, subject *'Fishway Observation," by Mr. F. L. Abbott, Superintendent of Fishways at Bonneville Dam. (Copy of memorandum and letter of transmittal included in Appendix l) "Fish do at times, rub the top and sides of orifices, but several different observers agree that they saw no fish passing through which, in their opinion, rubbed hard enough to be injured. From my own personal observation, I am not prepared to say definitely that fish are not in some instances injured." Two 200 foot reels of 16 mm., motion picture film showing the actions of the fish while passing through the submerged o-ifice were taken, and these are kept at Bonneville Dam in the office of bhe U. S. Corps of Engineers. 10 Figure 5«~Submersible chemiber built by U.S. Corps of Engineers to observe fish movement in the Bonneville fish ladderi 11 SECTION II ADTJLT FISH V.CRIt.UTf STUDIES - 1946 Float Experimento As part of the prof,ram of studies to determina the extent of iriortality of fishes in the Col-ombia Hiver belaw Boi.ae-/ille Dam in 1946, it was considered advisable to learn the directioi-i anc iriflnence of wind drift dvirin^ the peak of the fall run of salmon passing Bonneville. We believe that this infonnation vrauld enable u^ to determine the speed at which the river carried floating dead fish dov^ns tream. To obtain such data, 100 wooden flDats were oonstj-jc ted that would be subjected to approximately the SFjne degree of wind, wave, and current action as floating dead fish (Figures 6 and 7). The body of each float was of wood, 2 inches thick, 4 inches deep, 24 inches long, and painted bright yellow. Holes were bored in the underside of each, and two railroad spikes were inserted, one on each side of the center and 12 inches apart. Two 8-penny spikes were aliiO driven partway into the underside, one on each side of the center and 18 inches apart, to balance the floats and to keep them partially sabmergedo Each float v/as fitted with a red and white flag, tied to an 18 inch wire rod mast. Fifty floats had the red half of the flag on top, aud the other 50 had the white half on top. The flags, three inches wide and ten inches long, offered very little resistance to the wind. Since there is always a marked difference in the rate of flow of water between the spillv;ay channel and the powerhouse channel daring the low-water period of August and September, it was decided to release EG floats in each channel. Accordingly, at 1:00 a.m. on August 28, 50 floats with white=top flags were released in the powerhouse channel. At the time of release of the red-top floats in the spillway section, all spill-^fey gates had been c losed, resulting in nearly dead water in this channel, and we decided to use only the floats with v/hite- top flags in detenr.-Jnin^- the rate of river flow. Nineteen of the red-top floats went aground on chi end of Bradford Island. At 4s00 a.m., spillway gates v/ere opened, and as a result, sufficient current developed in the channel to take tnt 31 floats released after that time downstream to the confluence ■■£' the ~'r. channels. Water was flowing through the powerhouse channel at about 92,000 cubic feet per second during the experiment (Appendix, Table 1/. Two observers left the dam in a boat at 5:00 a.m. August 28, to follow the floats downstream. They saw floats distributed along tnair route for the first seven miles below the dan^ The "Sandy'» arrived at Cape Horn, 13 miles below Bonneville, at 6:30 a.m., where the observers remained to record the time the floats passed. The first float passed Cape Horn at 9:05 aorti.. Table 4 is a record of the day's observations. 12 ^ Fif>ure 6.— Wooden float used in experiment to determine direction and influence of wind drift 'belov; Bonneville Ds.m. 13 Figure 7. — Position of wooden float in water. 14 Table 4<> Number, hour of appearance, time elapsed, and rate of travel of red-top and white-top floats released at Bonneville Dam 1:00 ai,m. Aup>ust 28, 19^, and observed passing Cape Horn, 13 miles dO'wnstream* Red- top 'l/ 1 White-top ZJ floats floats Time Observed Time elapsed; (hours) ! Rate of tir-avel (miles/hour) NOo No. 1 1 1 1 1 X 1 1 1 7 1 1 1 1 1 1 9;05 a.Ti, B«08 9s08 a.-Ti, 8.13 9:26 aomo 8.43 9:32 asm* 8o53 9:40 aamo 8.67 9:46 a.m. 8.7? 9:56 a.m. 8.92 10 :01 a.m. 9.0E 10t20 a.m. 9o33 10:21 a.TC. S.35 10:33 a.m. Q C - 10:36 a.m. 9.60 10:54 a.m. 9.93 11:02 a.m. 10.03 12:06 p.m y 1:00 p.m. 12.00 1:38 p.m. 12.6 3 2:10 p.m. 3/ :..60 1.-34 lo52 lo50 lo48 i«45 1.40 1.3? lo3o ?..35 7.»3C 1.29 3/' :'.';; 08 1.03 3/ 16 l/ Fifty red- top floats were released in s piTTway cmfms'I." Of "these, ~ 37 were beached on the Washington shore and 11 were unaocoimted for. 2/ Fifty white-top floats were released in povrerhouse channel. Of these, "~ 11 were beached on the Y/ashington shore and 2 3 were unaocoujited for. 3/ Rate of travel not calculated because of late start. Other observers left the dam at 9:00 a.m. m anothe_-° boat, arriving at Ellsworth cannery, 33 miles beljw Bonneville, a-c noon. Floats were seen along the route for the first 1£ miles below Bonneville and although observations were continued at Ellsworth cannery until E :00 po^..., no floats were seen. Therefore, more than 16 hours were required for the floats to travel the 33 miles from Bonneville to the cannery. At 2:11 p.m., the observers otationed at Cape Horn started back upstream and examined those sections of the Washington shore where dead fish had previously been found. .Th«iy fo-and 18 red-top arid II white-top floats beached on the Washington shore between Cape Horn and Butler's Eddy, a point five miles below Bonnsville, and 19 red'-top floats between Butler's Eddy and Bonneville, We believe that 11 red" top and 2 3 white-top 15 floats unaccounted for went aground on the Oregon shore, which was not checked because of engine trouble in the boat. Two days later three white-top floats were found beached on the Washington shore Just above Ellsworth cannery, but no floats were observed on the Oregon shore. Observations of Dead Fish. Reports at various times had reached the U. S. Fish and Wildlife Service and the U. S. Corps of Engineers that great numbers of dead fish were floating below Bonneville Dam in the vicinitj'' of Ellsworth cannery. We decided, therefore, to station observers at Ellsworth cannery on the day following the peak of the fall run of chinook salmon at Bonneville Dejn (Appendix, Table 2), on the assumption that dead fish would appear in the river in greatest numbers during and following the time when the fish were most numerous at the dam. It had been determined from our recently completed float experiments that dead fish originating at Bonneville would drift dovmstream at about one and one-half miles per hoiir (Table 4), so that dead fish from the dam shoiild cover the 33 miles to Ellsworth cannery in about 43 hours, Salmon and trout sink immediately after death. Decomposition soon begins, causing gas to form within the body of the fish. When a sufficient quantity of gas has been formed, the carcass is buoyed up and floats, provided, of course, that the gas is trapped within the body of the fish, l/ Dead Fish Below Bonneville. The Ellsvxorth cannery wharf was chosen for the place of observation because the main river channel touches the end of the wharf, and it is in this main channel that nearly all of the drift travels o Furthemiore, the wharf is high enough above the water level that observers could readily see any floating fish that might pass. Tvro men were stationed at this point, one to watch for the floating fish and the other, in a power boat, to pick up the fish. The number of dead fish observed at this point is recorded in Table 5 and it can be seen that during 64 hovars of observation covering a period of 8 days only 10 dead chinook salmon were observed. On September 10, the observers examined both shores by boat from Ellsworth, to Vfashougal, Washington; during seven hours of observations, no dead salmon or steelhead trout were observed. On September 19 the boat proceeded to Bonneville Dam and during the seven and one-half hours of travel time, three dead chinook salmon and one dead steelhead trout were observed. TT" Observations made by Charles B. wSde, Aquatic Biologist, U. Si Corps of Engineers. The full text of his report is included in Appendix II. 16 Table 5. Number of dead ohinook salmon and steelhoad trout seen floating in the Columbia River by observers on the wharf of the Ellsworth cannery (approximately 30 miles below Bonneville dam) during the perioa September 10-17, 1946. Date 1 Pe: riod : Hours : Chinook : salmon s Steelhead 1946 ; aom • p.m : trout Sept. 10 7;00 _ 3 s 30 8 1/2 0 0 11 8s00 - 4s00 8 1 0 12 8sOO - 4!00 8 1 c 13 SsOO - 4j00 8 1 0 14 8sOO - 4;00 8 3 0 15 16 8s30 9sOO - 4:30 8 7 1/2 2 1 0 - 4:30 0 17 SsOO - 4:00 8 1 0 Totals 64 10 _!/■ 0 y' l/ The average number of dead ohinook salmon seen per hour during this ~ period was 0.156. No dead steelhead trout were observed. The aver- age for both species was 0.156 per hour, or 2,7 per day. Observers with a boat were also stationed at Cape Horn^ about halfway between the dam and Ellsworth to determine whether ail of the floating fish drifted as far downstream as Ellsworth. During our observations on wood floats, it had bsen learned that practically all of the river drift at this point came within 100 feet of the Washington shore, making it very easy for an observer to see dead fish float by. As at Ellsworth, one man watched for the floating fish and the other picked up the fish from the boat. Here, however, to prevent duplication of count, the boatman tagged and replaced the fish in the river for possible later recoveiyat Ellsworth. Table 6 shows that during approxi- mately 52 1/2 ho^irs of observation spread over a 9 day period 11 chinook salmon and 3 steelhead trout were observed. None of the tagged fish were recovered below Cape Horn. 17 Table 6. Nvimber of dead chinook salmon and steelhead trout seen floating in the Columbia River near Cape i^rn (approxiraately 13 miles below Bonneville Dam) durinf; the period September 10-19, 1946, Date • Period • • • Hours ; Chinook salmon : Steelhead 1S46 s aom s p .m. s : trout Sept. 10 8jOO . 2:00 6 1 0 11 7s45 - 2;05 6-4/12 2 0 12 7:45 - 2:00 6-3/12 5 0 13 8:00 - 1:45 5-9/12 0 1 15 9s00 - 1:00 5 1 1 16 7:55 - 1:55 6 2 0 17 8:50 - 1:45 5 0 0 18 7:55 -, 2:10 6-3/12 0 0 19 7:30 - 1:30 6 0 1 Totals 52-7/12 11 y 31/ 1/ The averaf,e number of dead chinook salmon seen per hour during this "" period was 0.209 and the average number of dead steelhead trout seen per hour was 0.057; the average for both species was 0«266 per hour. This would average 6.4 fish per day. During this period, 16 to 18 sturgeon fishermen between Bonneville and Cape Horn were using 10 to 20 dead salmonoid fish per day for bait. En route to Cape Horn and during the subseauent return trip to the dam, the observers picked up a few beached dead fish. These are recorded in Table 7. Table 7. Number of dead chinook salmon and steelhead trout found floating in the river or beached on the Washington shore betv;een Bonneville Dam and Cape Horn during the period September 10-lS, 1946 Date 1946 Chinook salmon Steelhead trout Sept. 10 11 12 13 14 15 16 17 18 0 Z 6 0 0 0 2 1 0 0 0 1 1 0 0 0 0 0 Totals 11 18 Uo So Coast and Geodetic Survey charts for the Columbia River from Vsncouver, Washington, to The Dalles, Oregon have been reproduced in Figures 8 and 9, and have been marked off in 1-mile sections from The Dalles, Oregon, to Lyle, Washington, and from Bonneville Dam to Cape Horn, Washington. The numerals in the circles refer to the numbers of dead fish found in each 1-mile seotiono Only fish found in 1946 during the period of the fall run are included in the figures encirclede Figure 8 also includes 21 dead salmon and steelhead trout which were picked up just below the spillway section on September 6 and October 3, 1946. Dead Fish Above Bonnevilleo It was decided to conduct the same intensive sef rch for dead fish above Bonneville Dam as below in order to compare the rate of mortality of fish that had passed over Bonneville Dam with those that had not surmounted the ladders. Accordingly, obser- vers were stationed at The Dalles, Oregon, from September 10 to 19, inclusiveo With the aid of a power boat, these men made a search for dead fish between The Dalles, Oregon, and Lyle, Washington. The section of river near The Dalles is roughly the same distance below Celilo Falls, a natural barrier, as Cepe Horn is belov/ Bonneville Dam, an artificial structure. Figure 9 shows the distribution of the fish found. Table 8 shown that in 81-1/2 hours of observations 93 dead salmon and steelhead were found. On September 23, the boat returned to the dam. En route to the dam 11 dead chinook salmon jf9te found dviring 5 hours of obeorvation» Table 8. Number of dead chinook salmon and steelhead trout seen floating in the Columbia River in the vicinity between The Dalles, Oregon, and Lyle, Washington, (approximately 13 miles belov; Celilo Falls) during the period September 10-20, 1946. Date : Period : : Chinook : Steelhead 1946 s a.m 1 p.m ; Hours : salmon : trout Sept. 10 8 ;00 - 4 ! 30 8 1/2 4 2 11 8 ;00 - 4 : 30 8 1/2 0 0 12 8:00 - 4:30 8 1/2 IS 2 13 8:00 - 4:30 8 1/2 11 0 14 8sOO - 12:30 4 1/2 2 0 15 8:00 - 4:30 8 1/2 8 1 16 8 :00 - 4 : 30 8 1/2 9 1 17 8:00 - 4:30 8 1/2 6 0 18 8:00 - 4:30 8 1/2 19 3 19 8-11 - 1-5 7 11 1 20 9-11 2 0 0 Totals 81 1/2 831/ 10 1/ 1/ The average number of dead chinook salmon seen per hoxxr during this period was 1.018, and the average number of dead steelhead trout seen per hour was 0.123} the average for both species was 1.41 per hour. This would average 27.4 fish per day. During this period approximately 15 sturgeon fishermen were fishing between Celilo Palls and the point of observation. However, most, if not all, of these men used lamprey or smelt for bait. 19 Figure 8.— Approximate location and number of dead fish found between Bonneville Dam and Cape Horn, Washington, 1946. Figure 9.— Approximate location and number of dead fish found between BonneTllle Dam and The Dalles, Washington, 1946. Dead Fish Used by Sturgeon Fishermen<. It is the practice of many Colvnnbia River sturp;eon fishermenj, above and below Bonneville Dam, to pick up floating dead salmon and use them for baito In order that the record of dead fish in August and September 1946 might be mad© as com- plete as possible and to try to adjust our observations by allowing for dead fish thus used, we decided to interview as many of these fishermen as we could reach. The fishermen fishing for sturgeon below the dam reported that one or two dead salmon per man were picked up each day during the period August 15 to September 15« As far as could be determined, there were only ten fishermen who used floating dead salmonj the other six or eight used either lamprey or smelt for bait. It migJit, therefore, be assumed that ten dead fish were picked up each day from mid-August to mid-September by sturgeon fishermen below the damo A commercial fisherman who fishes for sturgeon in the vicinity of The Dalles, Oregon, 50 miles above the dam, stated he had seen about ten "floaters" (dead salmon) per day during the period August 15 to September 15, 1946. He did not remove the fish from the water. According to his further statement, there were in September about 15 men fishing for sturgeon b etween Lyle and Celilo Falls » He further stated that only one or two fishermen above the dam used dead salmon for bait and that most of the hook-and-line fishing is dona using lamprey or smelt as baito SIMN'LA.RY 1. An incomplete record of mortality of adult salraon and steelhead trout occurring in the Columbia River at Bonne^ville Dam and for a dis- tance of several miles below the dam has been kept by the TI. S. Corps of Engineers each year since the dam was completed In 1938 (Appendix, Table 1-8) . 2, Fish counters at Bonneville Dam kept incomplete records of the injured fish passing over the counting boards in the fish ladders o Observations were conducted in May 1943 and during June, July, and August 1946. No attempt was made to record the total number of injured fish as compared with the total number of fish passing the counting boards. Instead, however, injuries were recorded for only a portion of each day's runo A continuous abrasion which extended from the back to the belly was tabulated as a net injury. Often wounds or cuts along the body or head were listed as other injurieSo Since a counter could observe only one side of a fish as it swam over the board, the numbers of injured fish seen were doubtless less than the total number of injured fish passing. In 1946, 6.4 percent of the ntanber of fish in the samples observed showed net injuries and approximately 3.7 percent showed injuries attributed to other causes. 22 3» A comparison was ir.ade hotween the numbers of injiird fish appearing in the adult chinook salmon run arrivinp, at Pig IVhite SaLrion Hatchery, about 30 miles above Bonneville Dam, and at Bonneville Hatchery, about one mile below Bonneville Dar « Ho great difference was found to exist in the percent of injured fish at the two locations , For example, 2 3 percent of the fish examined at Big V/hite Salmon Hatchery had dorsal- fin abrasions, and slightly more, or 26o5 percent, of the fish below the dam at Bormeville Hatchery had similar injuries. These injuries were undoubtedly caused by fishermen's nets. Other types of injuries, the origin of which is not knowrij occurred in 1.7 percent of the salmon examined at Big White and 2.4 percent of the salmon examined at Bonneville station. 4. A submersible observation chamber was constructed by the U» S* Corps of Engineers for the purpose of directly observing and making a photographic record of the action of salmon passing through submerged orifices in one of the fish ladders at Bonneville Dam. Neither the direct observations nor the moving picture records showed fish being injured in ladder. 5. One hundred wood floats, simulating floating dead salmon, were released at Bonneville Dam to determine the time required for fish that might die at Bonneville to be carried downstream past Ellsworth cannery. On August 28, 1946, when the river was flowing 92,000 cubic feet per second, the average rate of flow of the rivpr was foim'l to be between 1.C3 and 1.61 miles per hour. Therefore, floating dead fish at Bonneville Dam should drift by Ellsworth cannery (33 miles belov/) about 43 hours after leaving the dam. Since about 72 hours are required for salmon to be buoyed up sufficiently to be carried by the current,* the total time elapsing between the death of a fish at Bonneville and its appearance as a floating carcass at Ellsworth should be approximately 115 hours. 6. A count of the nurabers of floating dead salmon above and below Bonneville Dam was made during the peak of the fall run in 1946. During 64 hours of observations over an 8-day period, 10 dead salmon were seen floating by Ellsv/orth cannery, and 3 dead salmon and one dead steelhead were observed en route to Bonneville Dam from Ellsv/orth on September 18 and 19. Fourteen dead salmon and steelheed were recorded and tagged as they passed Cape Horn (about 13 miles below Bonneville). These fish were not observed at Ellsworth, Tfashington. In addition to the fish floating past Cape Horn, the observers noted 13 dead fish beached on the shore between Cape Horn and Bonneville Dam. Thus, in about 72 hours of search between the dam and Cape Horn, 27 dead fish were counted. Above Bonne- villa Dam, the observers saw 104 dead fish in about 86.5 hours of intensive search during the same period. «Wade, 1945, see Appendix. 23 CONCLUSIONS lo The great numbers of dead fish reported in previous years below Bonneville Dam did not appear in 1946 durinf, the period of investigation, £. Floating dead fish were foujid in about the seme numbers above and below Bonneville Dam. 3. Iniured fish were found at Bonneville Hatchery below Bonneville Dam and at Big White Salmon Hatchery above the dam in approximately the same proportions. 4 Most injuries to the fish observed are traceables to fishermen's gill nets J none of the injuries were directly traceable to conditions at Bonneville Dam. 5. Most net injuries were not fatal to fall-run chinook salmon at hatcheries above and below Bonneville Dam in 1946. 24 APPENDIX TWBLE 1 RIVER FLW IF CTIPIC FFET PER SECOTO - BOMEVILLE DAM August 1 - September 15, 1946 Date Flow Date Flow September 1 117,000 2 115,000 3 102,000 4 102,000 5 100,000 6 99,000 7 110,000 8 95,000 9 112,000 10 109,000 11 109,000 12 110,000 13 112,000 14 112,000 15 109,000 August 1 22 5,000 2 212,000 3 193,000 4 191,000 5 184,000 6 173,000 7 174,000 8 189,000 9 191,000 10 142,000 11 130,000 ]2 160,000 13 151,000 14 144, 000 15 140,000 16 139,000 1? 161,000 18 113,000 13 134,000 20 117,000 21 114, COO 22 117,000 23 102,000 24 101,000 25 111,000 26 95,000 27 92,000 28 92 . -^oo 2S 67, 000 30 89,000 31 97,000 25 AFPET-TBIX ■K^PLE 2 BO^TTEVILLE COITTIT-CUIFOOK, STEFUIELf-D, BLTTriBACK, AND SILVER SAli/OF FOR YE^.RS A>'D MON'^HE DTIRITTr. MllTCE DFAD FISH OBSFRi/ATIOIIS Y/FRF C3TT)IICTED Dats 1938 Spec: Chinook 34,765 4.97, i 54 i.es of Anadromous ?:.ol- Steelhead 29,231 46,618 Blueback 2,097 2 3c Silver August September 3,070 10,995 1339 Dead fish studies were not conducted this year 1940 duxy Aaf,uit Septembei Ootober 14,938 C8,643 240, r.OO 3,765 61,171 46,071 64,377 1, 78G 65.885 -,. 3,063 1,451 ^^ 10,165 ^. 213 1941 April 51,486 May It., 145 Jane 7,015 July J, 39c Aagac t 12, 590 Sept'-mbe:.- 351, S67 October 7,179 6,392 1,518 994 21,940 29,500 50, o42 3,980 299 ±0 -' JW 2 3,536 — 39,193 ~ 1,615 1,317 43 16,061 »- 369 1942 July August S&pteniber 11.816 i:i,3£i ■;.■'• '^ P ■ c . , jO^ 303,995 i, 588 19,905 41,973 76,322 12,624 41, 301 1,477 49 1,193 11,061 1943 June 5,*40 July 3,::-.4 August 28,985 September 201, 414 0c;tober 3, 354 1,554 7,755 29,894 41,061 2,444 4,525 — 33,613 «« 1, 697 762 1 1,676 89 125 26 APPENDIX TABLE 2 Cont'f,, 1344 Chinook Steelhead Blue back Silver May- 15,127 2,227 16 ^w June 4,363 1,169 3,098 -. July 8,241 21,868 11,171 »» Augus t 55,468 24, 508 659 1,052 Saptember 139,254 35,907 125 3,021 1945 July 16,327 24,600 6,903 2 Augus t 32,254 40,483 498 239 September 189,675 40,194 10 533 1946 April 14,179 9,839 9 M>B May 53,313 5,481 67 ~- Jure 30,051 3,265 7,805 = - July 2C, 960 20,559 64,704 22 Augus t 45,421 58, 356 1,746 227 September 277,075 36,296 21 3,609 TABLE 3 DEAD SAmON AND S TEELHF:A.D TROUT FOTJim BETWEEN BONJIFVILLE DAM AMD MT^LTNOMAH FALLS 1938 - 1S4S Dats Location Total Total Dead Hours Fi^h Ol/se 'ration 19 38 1939* 1940 1941 1942 1S43 1944 1945 1946 *No dead fish obserTations, 187 24 226 88 561 208 142 72 320 96 19 48 192 104 102 168 27 APPE?TDIX TABLK 4 RFCO^ OF DFAD FISH FCTmD C0LT1J.IBIA "RIVER m^mtNLLLE Di'jl - Min.T:T*T':'''AF FALLS Augus t - September, 1938 Speaies Monthly Da te Chiriook ~T"t--) e 1 h e a d Bluahack Si Ivors Total Total 1936 August 8 4 - - » 4 4 September o 94 ic 10 88 - - - 88 187 TABLE 5 RECORD OF DFAD FISH FOIHTO COLUMBIA RIYER BOHNEVILLE Dm - MULTIIO.MAH FALLS Jnl^r - October, 1940 Monthl; Dats Chinook Steelhead Blueback Silvers Total Total T»^o July 6 7 - - - ^ 2 Sept?mbe: ., 4 42 8 6 12 19 14 6 17 15 13 28 19 1 20 16 25 59 Gctooar 10 2 42 2 - - 21 1 - - 7 2 - - 18 11 - 1 40 1 21 61 21'; 28 APPEMDIX mBLE 6 R]:CORD OF DEAD FISH FOUND COLT^'BJA RIVFR BOTOIEYILLE DAM - MULnOMAH FALLS April - October, 1941 Species Date Chinook Stee 17 3 24 3 - , c n ■*. "" 8 11 1 15 15 - 22 17 1 5 7 a> 12 7 2 Steelhead Blueback Silvers Monthly- Total Total 1941 April Ma'/ June July Aug. S c p V fl &;t. 19 8 - 2 2.6 11 1 3 3 21 1 2 iC 21 3 2 17 8 3 2 24 10 10 5 31 7 2 1 r- _ 2 „ 14 2 4 - 21 J. 1 - 28 2 6 - 4 28 3 „ li 83 14 -. 18 128 9 _ 25 19 2 - 2 19 4 _ 3 10 — - i. 1 1 - - 27 ■= 15 - 18 72 7 - 10 - 10 - 15 42 " 24 _ ■cQ 13 = 25 - 10 98 ^ 2 - 6 > 2 - 8 18 1 32 - 97 4 141 - 21 291 ^ 23 - 10 - 1 34 ta APPENDIX TA.BLE 7 RECORD OF DEAD FISH FOUND COLUMBIA RIVER BONNEVILLE DMI ~ MULTN'OMi-\H FALLS Juno - September, x942 Species Total Monthly Date Chinook Steelhead Biueb ack Si . lv«rs Total 1943 Juno 23 2 10 - 3 •=■ 0 0 July 13 9 14 1 7 - 22 16 6 1 2 - 9 23 6 - - =. 6 30 3 6 7 3 IB » g 59 Aug. ^ ! 6 10 4 26 2 3 - 6 13 Sept. ^ 29 17 38 3 ■> 41 70 TABLE 8 RECORD OF DE/.D FISH FOUND COLTHBIA RIVER BOOTIEVILLE DAM - MULTNQK.IAH FALLS June " October, 194g ____ Species Monthly Bate ntinook STeOinead BiueoacK: SfAve^'S Total Total T943 ""^ "" """" ~ "" ~"~~~ Jcno 16 2 - - ■= 2 19 4 _ - ^ 4 26 3 - - =, JS_ 9 July 2 4 - - » 4 16 4 1 1 - 6 26 5 _ - ^ S 15 Aug. 8 13 1 1 - 15 16 7 1 - - & 27 1 - - = 1 24 Sept. 9 146 9 - 1 156 20 60 - _ _ 60 216__ 0-t« 2 52 4 - - 5t 56 30 Date 1944 May 29 June 7 14 J-.:ly 6 Aug. 4 S^pt. 5 APPEIJDIX TABLE S RECORD OF DErlD FISH FOWID COLiriBIA RIVER BO^^^^EVILLE DAM - MIILTITOMR FALLS' May - September, 1944 Speoies Monthly Chinook Steelhead Blueback Silvftrs Total Total 2 1 1 2 1 1 7 2 TABLE 10 RECORD OF DEAD FISH FOIITID COLTMBIA RIVER BOm>TEVILLE DAM - MULTTTOKAH FALLS July ~ September, 1945 Species p n u 1 1 5 5 2 2 9 9 Date Chinook Steelhead 1945 July 10 11 1 17 13 8 25 4 8 31 4 5 Aug. 1 _ 3 14 1 - 20 1 « 23 2 1 Sept. 10 1 _ 13 77 4 19 31 10 26 5 - Blueback Siive.s Monthly Total Total 13 21 12 9 55 3 1 1 3 8 61 41 5 129 31 APPENDIX TA.BLE 11 RECORD OF DEAD FISH FOUND COLUMBIA RIVER BOl^TNEVILLE DAJ'l - MULTNCMAH FALLS April - October, 1946 Species Monthly Date Chinook Steelhead Bluebaok Silvers Total Total 1946 April 25 May 3 9 16 23 ■Jvjcie 10 20 July 11 16 24 Aug. 2 8 12 ♦Sept. 6 Oct. 3 5 4 2 6 16 2 6 6 2 2 7 7 3 2 1 1 5 1 2 16 2 6 * Dead fish foijnd September 10-19 are recorded in the text, page 20 and are not included here. 5 4 5 14 2 6 8 24 10 17 51 3 6 3 12 16 18 6 6 32 APPENDIX I COPY October 8, 1945 Memorandum To? F. M. Lewis Subject; Fishway Observation There has recently been constructed an inspection chamber or diving bell for use in observing aouatic conditions in the fishway system» Completion of the chamber was too late to make as thorough a study as might be desirable, but did give certain desirable information. !• It was the consensus of the opinion that fish are not being injured passing through underwater orifices. Although there appears to be a fairly rapid velocity which reouires some effort on the part of the fish to get through, it in no way taxes their capacity. 2. Fish do, at times, rub the top and sides of orifice, but several different observers agree they saw no fish passing through which, in their opinion, rubbed hard enough to be injiired. From my own personal observation, I am not prepared to say definitely that fish are not, in some instances, injured. But for reasons other than injuries, I am of the opinion that underwater orifices are of no help to the fish. 3« The first setting of chamber was just upstream of Weir 55. This weir forms the lower end of stilling pool below counting station. Visibility varied during observation from excellent to fair. During the time of best visibility conditions, fish were very numerous, and could readily be ob^served as far as 15'-0" feet away. Water conditions could hardly be improved upon in this pool. As thousands were passing up the ladder, it was possible to observe their general condition and actions. The opinion of all observers is that fish, upon reacning this pool, are in- clined to take it easy, probably resting. They are in TlO apparent hurry and in contrast to those fish seen on the surface of the pool, those in the lower depths are remarkably calm and lazyo They displayed no concern over chamber, and many were curious enough to i-jmain within inches of the windows for consid- erable periods of time. 4» Diver's underwater lights (1000 Watts) were used at times to light up the area adjacent to the orifice and chamber. The fish were in no way disturbed. Some even appeared to be fascinated by the lights and remained under the lights for minutes at a time. This would tend to disprove the idea that fish will not 33 cross counting board when lights are on. My own opinion is that it is a com- bination of white board and bright lights. My theory is the kick back or reflection from the board rather than the lights, is the cause of the turn backs, It is possible that all turn backs are females, exercising a woman's perogative. 5» After observing conditions in stilling pool water, the chamber was b.^-af ted to Weir 65 where water conditions are typical of the ladders as a whole. The chamber was first placed upstream of the weir, later down- stream. As was anticipated, entrapped air greatly handicapped observa- tions. Fish v/ere observed coming through, but indistinctly, and detail was lacking, although all observers were agreed the velocity through opening appeared less then Weir 68 (lower end of the stilling pool). However it was proved that entrapped air does go to the bottom of the pool. SDMMARY 1, Consensus of opinion by observers is that injury just forward of dorsal fin frequently observed by counters is not caused by underwater orifices. This opinion is substantiated by observing fish in after bay below power house. The fish clearly visible in taiiwater were observed to be marked before entering ladders. The fish entering Bonneville Hatchery were also observed and the same condition noted in about the same quantities as seen in the ladders. Most logical opinion expressed so far is, fish escaping from the nets are injured in the process of doing so, 2o My objection to orifices is, no place for fish to rest. Lack of any deposit of silt or debris indicates no still water in pools, From an operational standpoint they are excellent and very desirable, 3o Stilling pool below counting station is desirable so far as allowing fish to rest. That water below top of weir is practically free of current, and fish move and maintain themselves with a minimum amount of effort. At times there appears on the surface a great number of fish that would indicate congestion, but underwater observation proves this apparent congestion to be not true. 34 4. Artificial lights no detriment. 5. Entrapped air does permeate all areas of ladders o The entrapped air appears in the shape of rather large air bubbles, very different than sur- face conditions would indicate. Continued obsej-vations during the coming year is anticipated. /s/ F. A. F. L. Abbott "U.S. Engineer office Oct 14 8 25 AM '46 Portland, Oregon" 35 APPENDIX II 1NA.R DEPARTMENT PortlaiK',, O:''egon District Office of ths Area Engineer Bonneville, Oregon 28 August 1945 Subject? Tests to Detei-mine the Time Factor in the Floating of Dead Salmonoid Fishes, Bonneville Dam, 1945 o To J Captain R, Bo CochranCj Resident Engineer, Bonneville, Oregon.. INTRODUCTION It is evident from weekly patrols by boat on the Columbia River below Bonneville Dam, that some losses in salmonoid fishes occur either at Bonneville or in its vicintiyo Daring the past years some informa- tion has been gathered on the numbers of dead fish found below Bonnevillee This information seems to be of very little value, other than on a cer- tain date so many fish were recovered from within a certain area of the river and its banko Such information does not lend itself to an analysis of the fish losses occurring at Bonnc^^illeo Only after a complete study of the many biological and physical factors involved will it be possible to ascertain the effect, if any, which Bonneville Dam has upon fish fatalities o Also it may be pointed out that only after such knowledge is available can the proner remedial mepsures be takeno After examining many dead salmon below Bonneville, it became apparent that some knowledge of the relationship betv/een the physical appearance of the fish and the length of time that it had been dead would be very helpful in stud;.ang the downstream drift and other factors » Even a rough approximation of how -long the fish had been dead would perhaps yield some olue as to where it was killed. This test to determine the time factor in the floating of dead salmon is but a small part of the vrark needed to be done. Additional observations upon the progressive changes in physical appearance of the dead fish were made and are included in this report. METHODS Before beginning the tests, it was realized that it would be neces- sary to confine the fisn in some manner, so that periodic examinations could bs made. Obviously, this is not the normal conditions to which the natural river losses would be subjected, but it was believed that condi- tions would not be siif ficiently different to affect the results. It was deoiced to confine the fish in large meshed bags and to tether them to the shore o In the actual test this method proved satisfactory and the alternate method of placing them in a wire cage was not usedo 36 Subject: Tests co Dotcnai^.e the T-.me Factor in the Floating of Dead Salmonoid Fishes, Bonneville Dam, 1945, (Continued) Bags of No. 32, soft laid seine twine were made up in both 4- and 6- ino'n stretch mesh, of which the 4'-inch mesh proved to be the most 8atis= f'actoryo The bags were made large enough and long enoagh to accommodate the largest fish used, and the exces.-; length disposed of when smaller specimens were used. The greater circumference of the bags did not seem to hinder the holding of the smaller fish. The desired specimens were secured at the Washington Shore trap, and killed with the least possible damage to the fish., The specimens we;~e immediately placed in their bags and deposited in the holding area ;,.ocated along the Bradford Island side of the spillway f orehaj . The holding area was not only accessible, but provided water of sufficient depth and quiet"» ness to carry on the work. Total lengths of the specimens were taken, and the time they were placed in the water notedo Observations were made on the length of time it took them to float, hov; many floated, a:';d how long they remainded at the surface. Notes were also kept on the physical appear- ance of the dead fish. The test was carried out a second time to check the results of the first test. OBSERVATIONS Part 1 In this part of the tests, 11 chinook salmon were used. The essential information is found in the follovidng table; Speci- Total Placed Found Found on Time Required No. of hrs men Length in Water Floating Bottom to Float Floated (in hours) 1 I'B 1/2" 3:00 pm 2 -00 pm 4;00 pm 18 July 21 July 27 July Tl 146 2 2»3" 3:00 pm 2:00 pm 3 s 30 pm 18 July 21 July 30 July 71 217 l/2 3 2'3 1/2** 3:00 pm 2 :00 pm 4 ;00 pm 71 266 18 July 21 July 1 August 4 I'lO'* 3:00 pm 8:15 am 5:00 pm 113* 152 3/4 18 July 2 3 July 29 July 5 I'lO l/S** 3:00 pm 2 :00 pm 3:30 pm 71 165 l/2 18 July 21 July 28 July 6 1«9 1/2^ 3:00 pm 2 :00 pm 3:30 pm 71 165 l/2 18 July 21 July 28 July f qw 3 ',00 pm 2 :00 pm 8:15 am 71** 42*** 18 July 21 July 23 July I'g" 2:00 pm 8:15 am 5 -00 pm 90 153 19 July 23 July 29 July 37 Subject; Tests to Determine the Time Factor in the Floating of Dead Salmonoid Fishes, Bonneville Dairij 1945 (Continued) Speci- Total Placed Found Found on Time Required No« of hrs men Length in Water Floating Bottom to Float (in hours) Floated 9 2«9 1/4" 1:45 pm 20 July 8:15 am 23 July 4:00 pm 31 July 66 199 3/4 10 1'9* 3:30 pm 20 July 8jl5 am 2 3 July 8:15 am 1 August 65 264 11 1» 9 1/2* 3:30 pm 20 July 2 :30 pm 2 3 July 4:00 pm 3 August 71 193 1/2 (*) This specimen was almost floating at 2:00 pm 21 July. CircximstRnces made observations impossible on 22 July, and it is probable this fish floated up on that date or the evening of the day before. (**) Specimen 7 only partially floated to the surface, head up, body down. Was never olserved floating flat on the surface. ^>ic:t>:ti) Specimen 7 sank to bottom in a short time. Pulled to surface and examined, and wbs found to have one side of abdomen partly burst or eaten out. On 19 July observations were made on the physical appearance of speci- mens 1, 2 and 3 at the end of 2 4 hours. These fish looked as if they were freshly killed; their color was only slightly faded and the gills were still slightly pink. The body had become rigid and the flesh remained firm. There was no external sign of bloat in the abdominal region. The paired fins were not frayed and still lay close to the sides of the body. On 20 July specimen 8, which had been dead for 26 hours, was examined, and in general the appearance was similar to that observed with the first 3 speci- mens examined, the only noticeable difference being that there was slight evidence of bloat around the posterior part of the abdominal cavity. All specimens sank readily when returned to the water. At the end of 48 hours, specimens 1, 2, end 3 were jre-examined. The color was f nding badly, becoming mottled in appearance, and the gills were entirely bleached out, but not deteriorated^ 1^8 paired fins lay normally along the sides of the body, and were not frayed or torn. The skin was not broken and still clear of any coating of slime. The flesh was moder- ately soft to the touch, and the body had become slightly flexible. A slight bloat was evident in the abdominal region, and the abdominal walls were firm and hard, but not greatly distended. A slight but definite odor of putrification was evident. When returned to the water, they sank readily to the bottom. 38 • SubjBct; Tests to Dotermin© the Time Factor in the Ploating of Dead Salmonoid Fishes, Bonneville Dam, 1945 (Continued) On 21 July observations were made on the appearance of the fish float- ing on the surface. The fish lay on their sides in the water, with the belly slif,htly higher than the back. The abdominal cavity was well dis- tended with gas, appearing puffed out posteriorly. The paired fins ex- tended straight out from the sides of the body, evidently forced into that position by the pressure of gas inside the body. The surface of the skin was soft and dull, and the flesh soft and spongy. There were no marks or broken skin on the body. A strong and definite odor of decaying fish was present. The fish were again checked on the morning of 23 July; the side of the fish floating upward had turned brown (sunburnt) from exposure to the sun and air. The skin was leathery and wrinkled, and cracked when the fish was bent. The head and tail regions were beginning to develop a fungus growth. External evidence of bodily deterioration was beginning to show at base of anal fin and around anal opening. The skin had burst and the flesh beneath was exposed. The fins were becoming frayed and torn. The body was limp and the flesh soft and pulpy. A very strong odor was present. From this time on, until the fish finally sank, their condition became progressively worse. It would be very difficult, if not impossible, to even approximately define their physical appearance at any definite time, during this period, since it was characterized by the continued growth of fungus on the body and the rapid deterioration of the entire fish. Evi- dently the internal structxu"es were entirely decomposed for the fish floated as limply as a rag in the water. It seemed evident that the fish was held together by the skin. By the time they were ready to sink, only a slight agitetion was needed to Isrealc them up» Part 2 fhe second test was made partly to confirm the results of the first test, and to see if there were any great difference in other species. In the following table, specimens 1 to 4 are chinook, specimen 5 a blueback, and specimens 6 to 10 steelhead. ~ Speci- men 5* Placed in Water 2 lOO pm 26 July 2 :00 pm 26 July 2 :00 pm 26 July 3 ;15 pm 26 July 1«9 1/2" 3:15 pm 26 July Total Length 1»10" 2'1» I'S* Found Floating 5:00 pm 29 July 5:00 pm 29 July 5:00 pm 29 July 5:00 pm 29 July 3:30 pm 28 July Found on Bottom 4:00 pm 31 July 6:15 pm 5 August 2:00 pm 6 Augus t 4:00 pm 31 July 4:00 pm 7 August Time Required No. of hrs . to Float Floated (in hours) 75 47 75 75 73 3/4 48 169 1/4 189 47 240 1/2 39 Sutjeoti Tests to Determine tint: ixiue Factor in the Floating of Dead Salmonoid Fishes, Bonneville Dam, 1945 (Continued) Speci- Total Placed Found Found on Time Required No, of hrs. men Length in Water Floating Bottom to Float Floated (in hours) 6 I'll** 4j00 pm 5sOO pn 6sl5 pm 73 169 l/2 26 July 29 July 5 August 7 I'S** 4:00 pm 4;00 pn 2 :00 pn 120 142 26 July 31 July 6 August 8 I'll 1/2" 4:00 pn 3:30 pn 4:00 pm 95 l/2 192 l/2 26 July 30 July 7 August 9 ■ S'l* 4:00 pm 3:30 pn 2:00 pm 95 l/2 166 l/2 .: ,1 26 July 30 July 6 August 10 2» 4:00 pm 5:00 pm 9:00 pm 73 136 26 July 29 July 4 August (*) The blueback had been injured. A circular area 2 l/2 inches in diameter from which the skin had been abraded was present on the right side of the body. Observations similar to those in Part 1 were made on the physical appearance of the specimens. Under the gross methods of observation used, no difference could be noticed between the fishes of the two tests, except in the single blueback. This specimen raised to the surface much more rap- idly and deteriorated more quickly. Perhaps the external injury was even more extensive internally and caused a more rapid decomposition. SUMMARY A total of 21 salmonoid fishes were killed and placed under observa- tion to determine the length of time it took them to float, how long they remained at the surface, and their external physical appearance at various intervals • Chinook Steelhead Blueback Number of specimens 15 5 I Number raising completely to the surface 14 5 1 Average time required to 75 hrs. 91 \/Z. hrs. 48 hrs. float to the surface (3 days) (3 da* 19 l/2 hr») (2 days) Average time remaining at 152 hrs. 161 l/4 hrs. 240 l/2 hrs, surface (o da. 8 hrs.) (6 da, 17 l/4 hr.) (10 days) Variations in time remain- ing at the surface 2-11 days 6-8 days 40 Subject: Tests to Determine the Time Factor in the Floating of Dead Salmonbid Fishes, Bonneville Dam, 1945 (Continued) It should be pointed out that the observed times reauired for the specimens to float and to remain afloat is probably greater than the actual time in both cases. The specimens could have floated up or sank ajiy time between the time they were first seen or disappeared and the previous observation. A difference of as great as 24 hours is possiblco Observations upon the physical condition of the specimens as they floated to the surface would seem to indicate that it would be difficult for scavengers to destroy the fish sufficiently to prevent its raising to the s\arface, provided it was not held under water by some physical obstruc- tion. It is possible that fish v/ith cuts or skin abrasions would be more easily attacked and eatent The fish used in these tests developed a heavy growth of fungus, a condition not noticed in the natural river mortality to any extent. Perhaps the abundant fungus growth was due to the fish being held in more or less quiet water away from "tiie influence of v/lnd and current. It should be realized that the behavior of the fish under observa- tion would not necessarily be that of fish floating free in the water. Charles B. Wade Aquatic Biologist 41 Interior Duplicating Section, Washington 25, T.C. 83913 ^^ ,|,"BL WHOI Librae liifii. 5 WHSE 01009