Figure 13.— Salinity (%) at 200 ni., fall 1963. (The 183- and 1,829-m. depth contours are shown.) 



spring, one seaward from Cape Cook and the 

 other seaward from Willapa Bay, illustrate the 

 changes in temperature with depth and dis- 

 tance from shore as well as difference in tem- 

 perature along the coast between the northern 

 and southern parts of the area (fig. 15). 



Characteristically the decrease of tempera- 

 ture with depth throughout the water column 

 was inconsistent only within the halocline 

 which contained sporadic inversions not in ex- 

 cess of O.S'' C. Below the halocline the tem- 

 perature decreased logarithmically toward the 

 bottom. 



As was true with salinity, the most pro- 

 nounced changes within the area took place in 

 the upper layers. The dilute water near shore 

 had a weak vertical gradient. Offshore from 



Cape Cook the upper 50 m. was isothermal, but 

 toward the south, the magnitude of the sea- 

 sonal thermocline increased between the sur- 

 face and 30 m. Within the halocline off the 

 Washington coa.st the i.sotherms rose toward 

 shore over the Continental Shelf, but beyond 

 the shelf they sloped slightly downward toward 

 shore. The temperature increase from Cape 

 Cook to Willapa Bay extended to a depth of at 

 least 200 m. In the lower zone, the isotherms 

 were relatively level. Although the variations 

 of temperature at a particular depth below the 

 halocline were small, the tempei-ature distribu- 

 tion at 200 m. did show an unusual feature. A 

 tongue of cold water (<6.8° C.) extended 

 shoreward near the middle of Vancouver Is- 

 land, interrupting a band of warmer water 



236 



U.S. FISH AND WILDLIFE SERVICE 



