49 



20 



1.5 



10 



i'EB. JklAR. Apr. May. Junb. July. Aug. Sept. 



Oct. 



Kov. 



Dec. Jan. 



The curve shown in full rej^resents the relation between the depth of water 

 in which the crab pots are placed and the month of the year. The curve shows 

 the average of numbers supplied by fishermen from all the important fishing 

 centres of the Northumberland coast. 



The curve drawn dotted shows the depth of water where the velocity at the 

 bottom is approximately one foot per second. In constructing this curve, the 

 automatic records have been made use of, an average being taken of the wave 

 periods and also of the wave heights. In doing this, all " disturbed " days have 

 been neglected. It must be remembered that these records extend over one year 

 only. 



