SEA-FISHERIES LABORATORY. 161 
salinity due to variations in the inflow of Atlantic water 
could be detected in our district. 
Now, as we have seen, seasonal variations do occur in 
this district, but as already suggested in last year’s report 
they are probably due in great measure to an entirely 
different cause, namely, variations in the amount of fresh 
water flowing in from the land. 
The amount of this inflowing fresh water to the 
north-east of the line, Calf of Man—Holyhead, is very 
large, and is probably greatest during the winter months. 
The tidal currents in this area are also very strong and 
cause very thorough mixing of the waters, and the 
occurrence of the minimum salinity about February, 
therefore, accords very well with the view expressed above. 
The same explanation will hold for the Carnarvon and 
Cardigan Bay Stations, though the amount of inflowing 
fresh water and consequent salinity variations, as also the 
tidal effects, are much less important. If the salinity 
variations of these stations were due to the Gulf Steam 
Drift the minimum should occur in the autumn and not 
in the spring, as it actually does. Now, at Stations V, 
VI, and VII the minimum salinity does occur in the 
autumn, and there can be no doubt that in these cases the 
variations are due to the Gulf Stream Drift. The 
variations are, it is true, only small, but that is not 
surprising, for these stations clearly mark the farthest 
points in the Irish Sea at which the effect of the Drift is 
detectable. At all stations affected by land water, as in 
Cardigan and Carnarvon Bays, and at all stations N.E. of 
the line Calf of Man—Holyhead, the small effect due to 
the Gulf Stream Drift is entirely masked by the much 
larger effect due to the inflow of fresh water from the 
land. 
In this connection it is of much interest to note that 
