OCEANOGRAPHIC STUDY of the BURKE CHANNEL -ESTUARY
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p.; / OCEANOGRAPHIC STUDY OF tHE BURKE CHANNEL -ESTUARY 1966-1967 R.H. Herlinveaux ENVIRONMENT CANADA Fisheries and Marine Service Marine Sciences Directorate Pacific Region 1230 Government St. Victoria, 8.C. MARINE SCIENCES DIRECTORATE , PACIFlC REGION PACIFIC MARINE SCIENCE REPORT OCEANOGRAPHIC STUDY OF THE BURKE CHANNEL ESTUARY: 1966-1967 by R.H. HerZinveaux Victoria , B.C. Marine Sciences Directo rate , Pacific Region Environment Canada Septembe r 1973 Table of Contents Introduction . 1 AreaS' Studied 2 Facilities . 3 Program and Procedures: 1966 3 Program and Procedures: 1967 . 5 Results: 1966 A. Wind , Temperature , Salinities 7 B. Time Series: Burke Narrows 12 · . C. Drift Measurements . 13 Results: 1967 A. Time Series . • . .' 16 B. General Distribution of Surface Oceanographic Properties . • 19 C. Surface Drift Me asurements . 20 . D. Drift Card Program . • . 20 Continuous Current Meter Observations 22 E. • • Winds F. 25 Discussion and Conclusions . • • 26 Appendix . I . Scientific Party . Ack now ledgements . References . Lis t Figures . of . OCEANOGRAPHIC STUDY OF THE BURKE CHANNEL ESTUARY: 1966-1967 by R. H. Herlinveaux INTRODUCTION Burke Ch anne l is located on the coast of British Columbia approximately 240 mi les northwest of Vancouver (Figure 1) . It is the main route through whi ch pink salmon migrate into and out of the Bella Coola River system from the Pacific Ocean . During the period (April, May, June) \vhen the young pink salmon are circulating in the Burke Ch annel system prior to entrainment into the sea , it is believed that a vari able and often significant mortality occurs. It has been surmised that this mortality rate is associate d primarily with the interplay between several environmental factors; water movements may be among the mo st important factors since they may direc tly transport th e fish or alter migratory routes by modifying the sa linity dis tribution . Such movements can also concentrate or disperse organisms whi ch represent the food of the fish or , perhaps of comparable importance , they can influence the amount of , and variation in the nutrient supply which is of basic impo rtance to the production of this food vi tal to the growth and survival of the young salmon . - 2 - Pickard (19 61) has des cribed the general oceano graphic feature s of Burke Channel in his treatment of in lets of the B. C. coas t. Dodimead and Herlinveaux (1968) reported on spring oceanographic conditions in the channel during 1963- 19 65 . They considered the salinity , tempe rature and current obse rvations obtained from March through June in the area from Fitz Hugh Sound to the mouth of the Bella Coola River. The following report deals with the oceanographic ob ser� va tions obtained during 19 66 and 1967 as part of the Fisheries Res e arch Board overall study of the Bella Coola River Pink salmon survival migration and has been formulated with the intent of provoking speculation in the areas of study de pendent up on or tangent to the data which it includes. AREAS STUDIED The 19 66- 19 67 oceanographic program was confined to areas of the Burke Channel sys tem where the main concentration young pink salmon occurs . The system was divided into of three regime s of relative ly consisten t feature s (Figure 1): Uppe r Regime: Bella Coola to the j unction of Burke and Labouchere Channels . Middle Regime: From the Upper Regime to slightly south of Res toration Bay . Lower Regime: From the Middle Regime to well along Fitz Hugh Sound . - 3 - FACILIT IES The base camp was a 76- foot barge , the "VELELLA" , whi ch contained both living quarters and laboratory facil ities (Figure 2) . Oceanogr aphic observations were con ducted from the "MEL IBE ", a 24-foot aluminum day-work boat; from the "NOCTILUCA" (Fi gure 3), 34-foot work a boat with overnight accommodations; from the "INVESTIGATOR" , a 54- foot ves sel with a crew of three; and from the "A.P. KNIGHT" , a 72-foot ves sel with a four-man crew . Each of the ves sels performed adequately ahd was adaptab le to the existing conditions . PROGRPM AND PROCEDURES: 1966 The program was organized to monitor surface layer distribution of properties for comparison with the previous years of observation . Emphasis was placed on obtaining information on the Middle Regime around the Kw atna Inlet junction which had been missed on earlier obs ervation projects . The Kw atna In let area contains a factor of fresh water movement which will be apparent in the data included in thi s report . Another specific ob jective was to determine the effect of meteorological conditions on the oceanographic environment . The "VELELLA " was anchored at Bella Coola Wharf , Croyden Bay, Cathedral Cove and Fougner Bay for various periods of time. - 4 - The methods of operation were as follows: 1. One month of continuous recording from an anemometer and a barometer installed on Flagpole Point , North Bentinck Arm . 2. Vertical serial temperature and salinity observations were taken with an in situ s alinometer and a l-meter path length turbidity meter in order to define the longi tudinal dis tribution of properties from the head of North Bentinck Arm to the South Bentinck Arm junction . 3. in situ salinometer was installed on An an improvised towing body and towed at a l-mete r depth in various parts of the sys tem in order to determine the plan of dis tribution o f properties . 4. A current meter with a Savonius rotor was operated from the ves sel -INVEST IGATOR" , an chored on the sill at Hvi dsten Point in lower Burke Channel . The cur rent observations were accompanied by salinity and tem perature observations taken at a l-meter depth using an in situ salinometer . 5. Surface drift measurements were carried out using dri ft drogues--some with paravanes , others with a small parachute drogue . "Dead-heads " (drifting , semi submerged logs ) of about 30-fee t in length were marked and tracked for varying lengths of time . - 5 - PROGRAM AND PROCEDURES: 19 67 In 19 67 the study continued in the same three regimes and a major effort was made to gather extens ive oceanographic , meteoro logical and biological samp ling in the form of a time series . This invo lved continuous recordings and periodic samp ling . Once again the reg ime break down , although dependent upon the existence of con venient ba s, was innovative in that it involved on- location y observations of fish congregations along the migration route . The barge "VELELLA " was located at Bella"Coola Wharf , Croyden Bay , and Fougner Bay for periods of time convenient to the project schedule . From these bases , using the "INVEST IGATOR" and the "A.P. KNIGHT" , current metering buoy sys tems were set up and meteoro logical ob servation units were installed in various locations along the channel . Synoptic oceano graphic and biological observations were taken in the surrounding areas . The observations fell into three categories , covering several types of data col lection: 1. Meteorological observations: a. Maximum and minimum temperatures (barge) . b. Continuous air temperature recordings (barge ) • c. Wet and dry temperatures , twice-daily (080 0 and 18 00 hrs.). - 6 - d. Cloud cover records , tw ice- dai ly (barge) . e. Dai ly rainfall (barge). f. Continuous barometri c pres sure and ane mometer records at several locations down the system (Fi gure 4) . 2. Biological and optical observations: a. Secchi disc readings , twi ce- daily (barge). b. 3D-meter obl ique plankton tows , twice weekly , at stations down the inlet. c. Echo sounder traces , twice-weekly , at each station. d. Turbidity profiles , twice-weekly , at stations down the inlet . 3. Oceanographic observations: a. Continuous I-me ter temperature recordings (barge) . b. Temp erature and salinity profiles , twi ce dai ly (barge) . c . Temperature and salinity profiles , twi ce weekly at stations down the inlet. d. Pe riodic dissolve d oxygen concentration determination at sele cted depths and stations . e. Sea level me asurements at Bella Coola, Bella Be lla and Croyden Bay , (Tidal Surveys , Canadian Hy drographic Servi ce). - 7 - f. Continuous current meter obs ervations (2-meter ) at 20 positions . (Carried out in close cooperation with the Canadian Hydrographic Service , Tide and Current Surveys Branch. ) g. Surface drift obs ervations using dro gues and drift cards . RESULTS: . 1966 A. Wind , Temperature , Salinities The 19 66 oceanographic and meteorological project began with an incident which was to prove indicative of the variable conditions which prevai l in the area under study . A major freshet occurred on the Bella Coola River , and when it hit the lower reaches of the river , the barge , "VELELLA" , moored in the river below the town of Bella Coola , became a source of considerab le concern for all pers onnel invo lved . The river rose eight feet in 24 hours . The fish traps , anchored in the river to trap pink salmon , were swept out to sea . Next day an aircraft was chartered to search for one of the traps which had not been located and to determine how far the flood waters extended into Burke Channel. The trap was located aground , 7.6 mi les away from its original position; it had been transported this dis tance in 33 hours . During the same time period the freshet had dis tributed muddy surface water to a point be low Labouchere Channel , a di stance of 18 mi les . - 8 - After this initial event , the barge was taken out of the river and secured to the Be lla Coo1a Wharf and the observational program commenced. In the early spring the Bella Coo1a River dis charge alternates between cle ar and muddy periods asso ciated with interior and coastal runoff conditions .