MARINE FOOD FISHES 109 
seaweed, but towards autumn go out into deeper 
water. 
The cod is a predaceous fish, feeding on whiting, 
herrings, sprats, small cod and various crustaceans and 
molluses, and as nothing appears to come amiss to him 
the cod rapidly increases in weight. The best-known 
members of the cod family are the cod itself, the haddock, 
the whiting, the pollock, the ling, and the hake. From 
the angler’s point of view the pollock is probably the 
most important; it is usually found on a rocky coast, 
and trawling for him, with a short rod and a red rubber 
sand eel as a bait, often affords excellent sport. 
Since Sars first described the egg of the cod, it has 
been found that with the exception of the herring, all 
our important food fishes hatch from floating eggs. 
Apart from their variation in size, floating eggs are not 
all alike in appearance, and many of them can be 
recognised under the microscope. For example, the egg 
of the cod and the plaice consist of a perfectly simple 
yolk enclosed in an egg membrane. In the turbot, an 
oil globule is present in the yolk, and, further, the yolk 
may be partially or entirely divided up as, for example, 
in the egg of the sole and the anchovy. 
A few floating eggs are present in the sea practically 
all the year round, but they are most abundant in the 
spring and summer. 
The time that marine eggs take to hatch varies, as 
in the case of the eggs of freshwater fish, with the 
temperature of the water, and with individual fishes, 
