Several invertebrate taxa, including large numbers of chironoinids and 



larvae of C aenis sp. and Leuctra sp., are harbored by Cladophora . 



Whitton (15) further describes a generalized seasonal cycle for 



C. glomerata in temperate rivers: 



. . . In spring, the thick-walled overwintering filaments firmly 

 attached to rocks start to produce upright branches. When light 

 intensities are high, and the water temperature reaches about 10°C., 

 upright growth develops rapidly, and by early summer growths are 

 at a maximum. For one or more of the reasons described earlier, 

 the crops usually decrease, and the rate of vegetative growth 

 apparently slows down. In early autumn there is usually another 

 period of rapid growth giving rise to zoospores, which settle 

 on rocks and produce new filaments, and some of these themselves 

 produce zoospores. Much of the autumn crop may be derived from 

 such new filaments. In late autumn the upright parts of the 

 plants become detached leaving the basal fragments attached to 

 rocks. . . 



This closely parallels the seasonal cycle of C ladophora in the Yellow- 

 stone River. 



Large growths of Cladophora , coirmonly known as blanket-weed in 

 other parts of the world, can be a nuisance in many ways. Detached 

 masses washed up on shores can interfere with recreational pursuits , 

 particularly when the alga is rotting. Large submerged growths can 

 interfere with boating and swimming and are generally unpopular with 

 anglers because, as they complain, it interferes with their lines, 

 provides poor habitat for fish food and causes fish mortalities, (pish 

 kills in Cladophora infested waters may result more from sewage-de- 

 rived ammonia toxicity rather than from depressed oxygen levels due 

 to nocturnal respiration.) Algacides have been used for short-term 

 control of Cladopho ra while long-term control has been accomplished 



-19- 



