Secret life of a trout river /  [Videorecording] / 
National Geographic Society. 
 - Washington, D.C. :  National Geographic Society,  c1974, 1986. 
 - 1 videocassette (10 min.) ;  sd., col. ;  1/2 in + 2 teacher's guides. 
 - Bio-science series ;  51198. .
<br/><br/> Also issued as a 16 mm motion picture. 
<br/><br/> Discusses the eco-system of a trout stream. Focuses on the mayfly, the trout, the dipper, and the pike as elements of a food chain. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Stream ecology.<br/>Trout.