SEA-FISHERIES LABORATORY. 85 
ON THE MONTHLY OCCURRENCE OF PELAGIC FISH 
tGem IN PORT ERIN BAY IN 1918. 
By Anprew Scortt, A.L.S. 
In the previous reports on the pelagic fish eggs from the 
area of the Irish Sea adjacent to Port Erin, a definite classifi- 
cation for the adult fishes was adopted. The general dis- 
tribution throughout the year was then given under each 
heading. This system, no doubt, was the correct one. Tf, 
however, we wish to know what eggs are likely to occur in any 
particular month, it is necessary to go through the complete lists 
and tabulate the records. This takes time, and single records 
may be overlooked. | 
For the sake of simplicity I have made use of a rather 
different arrangement in this report. The number of hauls 
of the coarse, fine and vertical nets in each month 1s first 
given, and then the numerical distribution is set out. One 
sees at a glance when the eggs are likely to be present and also 
their relative abundance. It also shows the different catching 
powers of the various nets. One naturally expects that the 
coarser nets will catch a greater number of the larger organisms 
than the fine nets, especially when diatoms happen to be 
plentiful. Fine nets soon choke up and their fishing power 
becomes much restricted. Diatoms and other micro- 
organisms pass through the meshes of the coarse nets and the 
efficiency continues much longer. The vertical nets very rarely 
capture eggs. It occasionally happens, however, that pelagic 
fish eggs are captured by this method that are not represented 
in the horizontal surface hauls. This may be due to the eggs 
having acquired a slightly higher specific gravity than the 
surface water so as to sink to deeper layers. 
Bi-weekly collections were taken in the bay by the staff 
of the Biological Station as far as weather and unforeseen 
