SEA-FISHEKIES LABORATORY. 



315 



on the part of the fish to temperature changes, then it 

 ought to he possible to correlate the differential tempera- 

 ture changes with the fishery statistics. The greater 

 the drop of temperature in the Nelson Buoy area, for 

 instance, in comparison with the fall of temperature in 

 Red Wharf Bay, the greater should be the migration 

 from the former area to the latter. It was with the 

 object of testing this supposition that the temperature 

 tables in this paper were calculated. Fig. 4, for 



a 9 10 II 12. I 

 1909 



Text-Fig. 4. The mean fall of temperatures at the stations Liverpool 

 Bay and Nelson Buoy (high range curve), compared with the fall at 

 the stations Red Wharf Bay and Great Orme's Head (low range curve). 

 Figures on the vertical axis are degrees centigrade, on the horizontal 

 axis months. 



instance, is an attempt to represent the temperature 

 differences at the two fishing grounds. The low-range 

 curve is that for the mean of the two stations Nelson 

 Buoy and Liverpool Bar; and the high-range curve is 

 that for the mean of the three stations Great Orme's 

 Head, Red Wharf Bay, and Point Lynus. There are 

 certainly differences between the various years, for the 



