Seasonal Surface Currents Off the Coasts of Vancouver Island 

 and Washington as Shown by Drift Bottle Experiments, 



1964-65 



W. JAMES INGRAHAM, JR. and JAMES R. HASTINGS' 



ABSTRACT 



Release of a total of 1 ,044 drift bottles during four periods from April 1964 to January 1 965 off the coasts 

 of Washington and Vancouver Island, British Columbia, indicate a seasonal reversal of flow, southward in 

 April and July and northward in November and January, within 200 km (108 nautical miles) of the coast. This 

 study supplements those conducted off the Oregon and California coasts by other agencies. 



INTRODUCTION 



The Northwest Fisheries Center of the National Marine 

 Fisheries Service, Seattle, Wash. (Biological Laboratory of 

 the Bureau of Commercial Fisheries prior to 1970), has 

 conducted far-ranging research on fisheries problems 

 throughout the subarctic Pacific region from local coastal 

 waters of Washington to the central North Pacific Ocean and 

 the Bering Sea. Oceanographic conditions that affect the 

 distribution and abundance of fish stocks have been studied in 

 conjunction with fisheries research since 1955. Studies of 

 local ocean currents off the coasts of Washington and 

 Vancouver Island were emphasized in the oceanographic 

 research program from 1963 to 1964 (Ingraham 1967). The 

 purpose here is to summarize results of drift bottle 

 experiments in 1964 and 1965 which were not reported by 

 Favorite and Fisk (1971) nor by Fisk (1971). 



Although the general oceanic flow may appear as a simple 

 onshore movement, eddies form complex flow patterns 

 within about 500 km (270 nautical miles) of shore as the land 

 boundary causes the current to diverge toward the north and 

 south. These complexities were shown by dynamic 

 computations and from records of water properties for 

 several isolated studies at different times (Doe 1955; 

 Bennett 1959; Reid 1960; Budinger et al. 1964). Other 

 studies, using drift bottles to estimate surface water drift, 

 have shown some details of flow within 200 km (108 nautical 

 miles) of shore where reversals occur, with flow from the 

 north in summer and from the south in winter ( Dodimead and 

 Hollister 1958; Schwartzlose 1963; Burt and Wyatt 1964). 



Four oceanographic cruises were conducted aboard the 

 RV George B. Kelez in April, July, and November 1964 and 

 January 1965, which helped provide areal continuity in 

 nearshore ocean sampling between the Oregon and Canadian 

 coasts.^ During these cruises 1,044 drift bottles were 

 released along two lines normal to shore — one from Willapa 

 Bay, Wash., to Cobb Seamount and the other from Cobb 



'Northwest Fisheries Center, National Marine Fisheries Service, 

 NOAA, 2725 Montlake Boulevard East, Seattle, WA 98112. 



Mngraham, W. J., Jr., and D. M. Fisk. 1966. Oceanographic 

 observations off the coasts of Washington and British Columbia— April, 

 July, and November, 1964 and January 1965. Unpubl. manuscr., 96 p., 

 Northwest Fisheries Center. Natl. Mar. Fish. Serv., NOAA, Seattle, WA 

 98112. 



Seamount to Estevan Point, Vancouver Island, B.C. Twelve 

 corked, unballasted, short-necked (17 cm long with a 4'/2-cm 

 base) drift bottles were released at 21 stations during each 

 cruise. Ballast sand was not placed in the bottles to save 

 handling time. These particular empty bottles already floated 

 about 80% submerged and any improvement would be minor 

 compared to other inherent errors in the method. Only 

 minimum speeds are inferred by drift bottle data because 

 there is no way of knowing how long the bottle was on the 

 beach before recovery. Each contained a folded data card 

 with instructions in English, Russian, and Japanese and 

 four-digit serial numbers ranging from 6001 to 7044. A 

 reward ($1.00) was offered for the return of each card. 

 Recoveries from each cruise are discussed separately below. 



APRIL 1964 



From 20 to 28 April 1964, a total of 288 drift bottles was 

 released at 21 stations and 77 recoveries (27%) have been 

 reported (Fig. 1, Table 1). The recoveries suggest two 

 distinct regions with different flow features; 1) a southerly 

 drift at speeds of 15 to 30 cm/s about 167 km (90 nautical 

 miles) wide nearshore and 2) an offshore region of 

 questionable flow from which no recoveries have been 

 reported. These features are the same along both of the 

 tracklines. 



The 41 recoveries from the six inshore stations along the 

 trackline normal to the Washington coast were from the 

 Washington and Oregon coasts southeast of the release 

 locations. All 7 of the recoveries from the nearest inshore 

 station were reported from the southern Washington coast, 

 whereas, all of the remaining 34 recoveries were from the 

 Oregon coast. These reflect a dominant southerly flow of 

 surface waters at this time. A northward flow was reported in 

 April 1959 and 1960 (Schwartzlose 1963), and mixed flow 

 toward the north and south was reported in April 1961 and 

 1962 (Burt and Wyatt 1964). 



Along the trackline normal to the west coast of Vancouver 

 Island, 36 recoveries came from 72 releases at the six inshore 

 stations. Of the 15 recoveries reported from the three 

 stations shoreward of the 100- fathom curve, four were 

 recovered on the west coast of Vancouver Island north of the 

 drop location, indicating some localized northerly flow of 

 surface waters along the west coast of Vancouver Island. The 

 remainder of the recoveries from these three stations and 20 



