2005 Highlights:Two new types of propagation cages were tested this year; a floating cage system, and a “cage-on-a-cage” design which allows for easy removal of host fish.

Two new types of propagation cages tested this year in the Upper Mississippi and St. Croix Rivers.  The top photo shows a new floating cage system installed in the Upper Mississippi River, Pool 12, at Dubuque, Iowa (Ice Harbor).  This system is used to float standard propagation cages.  The bottom photo shows a “cage-on-a-cage” design which allows for easy removal of host fish (divers are show with the top portion of the cage containing host fish; the lower cage containing juveniles and sediment is still on the river bottom)). This cage design was used for propagation of winged mapleaf (Quadrula fragosa) in the St. Croix River, Minnesota.  Photos by Gary Wege, U.S. Fish and Wildlife Service.