132 W 

 50 N 



130 W 



15B W 



12B W 



48 N 



4B N 



44 N 



42 N 



40 N 



38 N 



Cobb Seomount 



- DRIFT BOTTLE RELEASE 

 NOVEMBER 1964 



132 W 



130 W 



128 W 



126 W 



124 W 



122 W 



Figure 3. — Locations of drift bottle releases and recoveries, RV 

 George B. Kelez, 6-16 November 1964. 



132 W 

 50 N 



48 N 48 N 



46 N 46 N 



44 N 44 N 



42 N 



40 N 



38 N 



46 N 



44 N 



42 N 



40 N 



= DRIFT BOTTLE RELEASE 

 JANUARY 1965 



30 N 



132 W 130 W 128 W 12G W 124 W 122 W 



Figure 4.— Locations of drift bottle releases and recoveries, RV 

 George B. Kelez, 13-17 January 1965. 



Davidson Current flowing northward off the coast of 

 Washington at 11 to 15 cm/s (minimum) and flowing toward 

 the northwest off the coast of Vancouver island at 13 to 17 

 cm/s (minimum); 2) recoveries 41 to 44 days after release 

 indicate the current still had a net northerly component as far 

 as 445 km (240 nautical miles) offshore; and 3) recoveries 60 to 

 70 days after release near Cobb Seamount were reported 

 both north and south of their release latitude. Many late 

 recoveries (70 days) were made from most of the stations 

 beyond 130 km (70 nautical miles), which showed a wide 

 range of recovery points from northern Washington to 

 southern Oregon. Their significance is questionable, but 

 multiple late recoveries probably suggest a large dispersion 

 of bottles from any one release station with a possible long 

 residence close to shore once the nearshore zone is reached, 

 followed by sporadic recoveries depending on the local 

 onshore transport. 



SUMMARY 



As part of an ocean survey of local seasonal conditions off 

 the coasts of Washington and Vancouver Island, 12 drift 

 bottles were released at each of 21 stations along two lines 

 from Cobb Seamount normal to the shorelines of each coast 

 during April, July, and November 1964 and January 1965. 

 These experiments extend our knowledge of drift of coastal 



surface water northward of the area of earlier studies by 

 Scripps Institute of Oceanography and Oregon State 

 University, providing data for another time period. 



Early recoveries from both lines of stations within about 

 60 days of release clearly showed the dominant seasonal 

 patterns of flow nearshore. Of the April releases 27% were 

 recovered, compared to lower recoveries in similar studies off 

 Oregon (13%) and off California (5%). The percentage of 

 recoveries decreased during July to 16% and was lowest in 

 November at 9%, but January recoveries were highest at 

 30%. Within about 150 to 200 km (81 to 108 nautical miles) of 

 shore, the surface drift was southerly during April and July 

 but speeds of first returns decreased from a maximum of 15 to 

 30 cm/s (minimum) in April to 5 to 11 cm/s (minimum) in July. 

 The direction of flow reversed sometime before mid-autumn, 

 for a well-developed northward flow at speeds of 5 to 8 cm/s 

 (minimum) extended along both the Washington and 

 Vancouver Island coasts beyond lat. 50°N in November. The 

 northward flow was also present in January but speeds had 

 doubled. Very little may be inferred about nearshore flow 

 from bottles released beyond 200 km (108 nautical miles ) from 

 the coast. Those released in November or January may be 

 recovered but move in a long complex path. Those released in 

 April or July appear to have been caught in the North Pacific 

 gyre as shown by Dodimead and Hollister (1958). 



