DAILY SEAWATER OBSERVATIONS ON THE PACIFIC 

 COAST OF CANADA 



By H. J. HOLLISTER 



Pacific Oceanogr<vphic Group 

 Nanavmo, B.C., Canada 



A programme of daily observations of surface seawater temperatures 

 and salinities has been in progress on the Pacific Coast of Canada since 

 1933. Fourteen sampling stations are located at strategic positions (Fig. 

 1) along the extensive coastline so that each station monitors the condi- 

 tions in a natural region. The majority of the stations are located at 

 lighthouses (Fig. 2) where the lightkeeper carries out the duties ot 

 water sampling in addition to his regular duties. 



The procedure and apparatus are quite simple. The observer takes 

 the daily sample during the last hour of the rising tide occurring in the 

 daytime. A two-ounce medicine bottle is inserted in clips attached to 

 a wooden rod and lowered to a depth of three feet. The bottle is stop- 

 pered with a rubber cork on the end of a guided brass rod, and the sam- 

 ple is obtained by pulling out the stopper. Fastened alongside of the 

 bottle clips is a brass protective case containing a mercury Fahrenheit 

 thermometer. The whole apparatus is left immersed in the sea for two 

 minutes, then the stopper is replaced in the bottle and the rod raised. 

 The observer immediately reads the temperature and records it on a 

 dated label already placed on the sample bottle, which he then seals 

 ^vith a wax-impregnated cork. Date, time of sampling and w^ater tem- 

 perature observed are also recorded on a data record sheet. 



The bottles are packed in cases of one hundred, and are shipped 

 to the central laboratory where the salinities are determined by a modi- 

 fied Mohr titration. The water temperatures and salinities are pub- 

 lished in annual volumes entitled, "Obsers'ations of Seawater Tempera- 

 ture and Salinity on the Pacific Coast of Canada." These data provide 

 a continuous record of the changes occurring in the marine climate of 

 the waters surrounding each station, and provide a backlog of informa- 

 tion which can be used to illustrate the year to year fluctuations in the 

 overall coastal oceanographic conditions. These data might provide 

 the only clue in determining why the fishery in a certain coastal region 

 changed in volume from one year to the next. 



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