SEA-FISHERIES LABORATORY. 



431 



prevail, e.g., is dependent upon strong ebb and flood. Of 

 the seven stations taken (see map), the greatest change 

 was recorded at station No. 3, but here the conditions are 

 to some extent abnormal, inasmuch as a brook enters the 

 estuary from the North, immediately in the vicinity of 

 this station. 



The effect of flood does not appear to be felt m the 

 estuary for at least one hour after it has been running 

 outside the bar, the strength of the river current being 

 sufficient to neutralise its effects. There appears to be a 

 fairly well marked banking up of fresh water on turn of 

 tide. 



The chart as it is here reproduced shows the 

 present (December, 1913) distribution of river channels, 

 which are continually changing. In consequence of these 

 changes there are distinct indications that Trevri 

 (Station 7) is now in the nature of a back-water, and often 

 contains Salter water than its position appears to warrant. 

 It was almost impossible to determine the differences 

 in salinity in the area consequent on the change from 

 neaps to springs, particularly so as the stations were all 

 perforce chosen to the North side of the estuary. 



Hydrographical Readings (Tabulated). 



October 31st. — Springs ; high tide, 9.5 a.m. ; observations begun 12.30 

 p.m. ; wind, W.S.W. strong. 



Stations. 



Tempcraturo 

 of Water. 



Specific Gra\ ity. 



9 



Aberdo vcy 



11-6 

 114 

 11-6 

 11-6 

 11-6 

 11-6 

 11 «8 



10245 

 10243 



3 



Wharf 



1 -023:, 



1 





10240 



*s 





1-0236 



6. 



7 



June, of Trerddol and Main Stream ... 

 Trevri 



1-02 in 

 10230 









