234 



A quatic Orga nisms 



Doubtless many of these eggs are smothered in mud and 

 many others are eaten before hatching. Suckers seek 

 out gravelly shoals, preferably in the beds of streams, at 

 spawning time. Dangers are fewer here and a single 

 female may lay 50,000 eggs. Yellow perch attach their 

 eggs in strings of gelatin trailed over the surface of 

 submerged water plants. The number per fish is still 



Fig. 141. A splash on the surface made by a carp in spawning. 



further reduced to some 20,000 eggs. Sunfishes make 

 a sort of nest. They excavate for it by brushing away 

 the mud with a sweeping movement of the pectoral fins. 

 Thus they uncover the roots of aquatic plants over a 

 circular area having a diameter equal to the length of 

 the fish. On these roots the female lays her eggs, and 

 the male guards them until they are hatched. With 

 this additional care the number is further reduced to 

 some 5000 eggs. Sticklebacks actually build a nest, by 



