RAINBOW TROUT 



Sahno gainhwri Richardson 



Lyndon H. Bond, Assistant Chief 



Fishery Research and Management Division 



Rainbow trout were introduced in Maine from the West Coast of 

 the United States. Their original distribution was from southern Cali- 

 fornia to southern Alaska, but the successful propagation in hatcheries 

 has resulted in introductions in many other sections of the United States. 



Rainbow trout that migrate to the sea are known as "steelheads" 

 and those that remain in fresh water are called rainbows. In Maine there 

 are no sea-run rainbows or "steelheads." All of the populations are resi- 

 dent in a limited number of streams in the Kennebec, Androscoggin, 

 and Aroostook River basins. 



Kennebec River rainbow trout are confined to the section of the 

 river from Wyman Dam in Bingham to the Solon Flowage above the 

 town of Solon. Rainbow trout are present above Wyman Dam in Pleas- 

 ant Pond Stream and a few, below Solon Dam; but the major sport fish- 

 ery is in the four miles of main river immediately below Wyman Dam. 

 The Androscoggin River rainbow trout fishery is confined to the cold, 

 spring-fed tributaries of the upper Androscoggin River in Oxford Coun- 

 ty. The Aroostook River has a few rainbow trout and they are oc- 

 casionally taken by anglers in the main river. 



The rainbow is the only spring-spawning trout in Maine. Studies 

 on the Kennebec River, in 1954 and 1955, indicated spawning started 

 about April 20, but the spawning period may extend from February 

 to June. Spawning was observed in all tributary streams accessible to 

 the rainbow trout, including streams that did not maintain a flow 

 throughout the summer. The rainbow usually spawns for the first time 

 at the beginning of its fourth growing season. Majority of the spawning 

 run is made up of fish spawning for the first time; however, the same 

 fish may spawn as many as three or four times. 



When the fish become mature and enter tributaries to spawn they 

 are quite silvery in appearance. As actual spawning time approaches, 

 this silvery coloration darkens. Prominent pink or reddish stripes de- 

 velop along the sides and the black spots on the body and fins show very 

 clearly. Older male rainbow develop a prominent, hooked lower jaw 

 and take on the typical slab-sided characteristics of an adult spawning 

 male. The spawning female is more silvery with less prominent reddish 

 stripes on the sides and with a rounded body conformation. 



39 



