SEA-FISHERIES LABORATORY. 9] 
movements of the adult fish in the Jrish Sea are very irregular. 
In some years great shoals of haddock are present throughout 
the area, and prove very valuable to the fisherman. In other 
years no haddocks are captured. It will be rather interesting 
if the occurrence of haddock eggs in what may be regarded as 
the centre of the Irish Sea in the early summer of 1918 indicates 
an important invasion of the adults at an early date. The 
coarse and fine horizontal surface nets averaged 9°1 eggs for 
each combined haul. The coarse nets caught 15°6 eggs each, 
and the fine nets 2°6 eggs. The vertical hauls taken during May 
averaged one egg each. That is the highest number captured 
in any month throughout the year by this method of collecting 
plankton. 
JUNE. 
Material: Coarse net, 8; Fine net, 8; Vertical net, 8 = 24 hauls. 
Coarse. Fine. Vertical. Totals. 
Rockling eggs af: oy es 66 5 1 72 
Haddock eggs... Ke Hi 1 0 0 1 
Dragonet eggs 10 0 0 10 
Sprat eggs 7 0 3 10 
urnard eggs 1 0 0 1 
Topknot eggs 15 1 at 16 
Totals... 100 6 4 110 
These figures show a further reduction in the number of 
eggs present. The whiting and the cod have disappeared. 
One of the gurnards is now represented for the first time by a 
single egg captured in one of the coarse net hauls. One haddock 
ege was also taken in a coarse net collection. The coarse and 
fine horizontal surface nets averaged 6°6 for each combined 
haul. The coarse nets captured 12°5 eggs each, and the fine nets 
0°75 eggs per haul. 
