Herald and News:  Flows are used to control a salmon disease caused by the parasite Ceratonova shasta.  According to Sascha Hallett, microbiology senior research associate, the purpose of the flushing flows is to mobilize sediment and reduce polychaete worm (invertebrate host of C. shasta) populations, thereby reducing the numbers of hosts available to produce the infectious state for salmonids (salmon and trout).