STICKLEBACK FAMILY (Gasterosteldae) 

 Key to the species of the stickleback family found in Maine 

 1 . Three free dorsal spines 



Threespine Stickleback 

 Gasterosteus aculeatus Linnaeus 



Free dorsal spines 5 to 11 2 



2. Free dorsal spines 5 or 6 



Free dorsal spines 8 to 11 



Brook Stickleback 

 Eucalia inconstans (Kirtland) 



Ninespine Stickleback 

 Pungitius fungitius (Linnaeus) 



The threespine stickleback and the ninespine stickleback may be found in 

 both salt and fresh waters. The brook stickleback is only found in fresh water. 

 Since the sticklebacks have little economical importance their habits and life his- 

 tories will be considered together. 



The sticklebacks are fishes of quiet, cool waters. Their spawning season 

 comes in the spring in May and June. Their spawning is interesting inasmuch 

 as 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 small twigs, bound together by the secretions from a modified portion of the 

 kidney of the male. The nest is constructed in quiet water where the flow is very 

 slow and constant. Luring a female into the nest where she lays a few eggs the 

 male follows and fertilizes them. As fish go the sticklebacks lay only a few eggs 

 generally less than a hundred. The male guards the eggs with a very belligerent 

 attitude readily attacking fishes much larger than he. The young are guarded 

 for a short time after hatching. 



Sticklebacks feed on smaller invertebrates, small fish fry and are accused 

 of eating the spawn of other fishes. 



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