STICKLEBACK FAMILY (Gasterosteidae) 



Sticklebacks are small fishes of little economic importance although 

 they have been used in recent experiments on animal behavior. Three- 

 spine, fourspine, and ninespine sticklebacks may be found in both salt 

 and fresh waters, but in any case they are distinctly shore fishes. The 

 brook stickleback is never marine. Sticklebacks are fishes of quiet cool 

 waters, and are frequently observed in backwaters having a barely per- 

 ceptible current. 



Their breeding and nesting habits are of interest. Spawning takes 

 place in the spring in May and June. The male builds a small nest about 

 the size of an English walnut among the aquatic vegetation. The nest 

 is a hollow spherical or cylindrical mass of grass and twigs bound to- 

 gether by the secretion from a modified portion of the male kidney. 

 The nest is constructed in quiet water where flow is very slow and con- 

 stant. The male defends the nesting area from other males and other 

 intruders. Once the nest is finished the male lures a female into the nest 

 where she lays a few eggs. The male follows and fertilizes them. Usually 

 a female will lay fewer than 100 eggs. 



The male guards the eggs presenting a very belligerent attitude by 

 raising his spines and readily attacking fishes much larger than himself. 

 The young are guarded for a short time after hatching. 



Sticklebacks feed on small invertebrates and small fish fry. 



92 



