OutdoorNebraska

44 Giant floater, Pyganodon grandis Description: The Giant Floater is a thin-shelled, inflated species than can get over 200mm. The shell is a long oval that is glossy and smooth with some exceptions. Their color can vary from light tan to green/brown to almost black. The nacre is white, sometimes with a light pinkish cast. The beaks are low and their sculpture consists of a series of double-looped ridges. Similar species: Adult Giant Floaters are so large and fat that they are hard to confuse with other mussels. Juveniles, on the other hand, can be similar to the Cylindrical Papershell and, especially, the Creeper. All three lack hinge teeth and have thin, smooth shells. Only the Giant Floater has the double- looped beak sculpture where the other two have single loops. Conservation status: G5, N5, S5. They are widespread and abundant over the whole state. Hosts: Black crappie, blacknose dace, blacknose shiner, bluegill, bluntnose minnow, brook silverside, brook stickleback, central stoneroller, common carp, common shiner, creek chub, freshwater drum, gizzard shad, golden shiner, goldfish, green sunfish, Iowa darter, johnny darter, lake sturgeon, largemouth bass, longnose gar, orangespotted sunfish, pearl dace, pumpkinseed, river carpsucker, rock bass, skipjack herring, white bass, white crappie, white sucker, yellow bullhead, yellow perch. Habitats used: Ponds, lakes, and sluggish mud-bottomed pools of creeks and rivers. Can be found in a variety of other habitats as well (Cummings and Mayer 1992). Quiet water with mud or mud-gravel bottoms but may adapt to lake environments (Oesch 1995). Found in rivers with sand and gravel beds but most common in reservoirs, lakes, and ponds with mud bottoms (Parmalee and Bogan 1998). Widespread and common species found in nearly every type of substrate and water flow (Watters et.al. 2009). Distribution: Wide distribution from Mexico through the central Great Plains up into Canada on the west and Alabama to Ontario on the east. Basically from the Appalachian Mountains to the 100 th Meridian. Collection notes: This species is widespread over all of Nebraska. Archeologically, the Giant Floater was fairly uncommon Comments: Our most common species, it is found throughout the state, probably due to the construction of numerous impoundments where it is able to do well. Its broad range of host fishes may also lead to its introduction into new waterbodies via the stocking of glochidia-infested fish. For instance, in the White River basin, they are only found in reservoirs, Carter P. Johnson Lake, Whitney Reservoir, the Chadron State Park pond and the Chadron City Reservoir.

• Cover