.........................................................................................................................................................1 Chapter 1. The Fish ........................................................................................................................................2 Overview ................................................................................................................................................2 Current Status of Bonytail and Razorback Sucker ..........................................................................2 Status of the Bonytail ..................................................................................................................2 Status of the Razorback Sucker ...............................................................................................4 Propagation and Stocking ...................................................................................................................4 Stocking Programs and Relative Success .......................................................................................6 Central Arizona .............................................................................................................................6 Senator Wash, California ...........................................................................................................6 Lake Mohave ................................................................................................................................6 Lake Havasu .................................................................................................................................6 Lower Colorado River (Downstream of Parker Dam) ............................................................8 Upper Colorado River ..................................................................................................................8 San Juan River .............................................................................................................................8 Prognosis ...............................................................................................................................................8 Study Objectives ...................................................................................................................................8 Ecology of Bonytail and Razorback Sucker .....................................................................................9 Capture Techniques ....................................................................................................................9 Bonytail ................................................................................................................................9 Larvae ........................................................................................................................9 Larger Bonytail ...........................................................................................................9 Razorback Sucker .............................................................................................................10 Larvae ......................................................................................................................10 Larger Razorback Suckers .....................................................................................10 Mortality Issues ...............................................................................................................12 Bonytail Life History ..................................................................................................................13 Physical Description .......................................................................................................13 Distribution and Abundance ..........................................................................................14 Diet ...............................................................................................................................14 Parasites ............................................................................................................................16 Age-Length Distribution ...................................................................................................16 Longevity ...........................................................................................................................16 Habitats and Habits .........................................................................................................17 Beaver Association .................................................................................................17 Movement .........................................................................................................................17 Reproduction .....................................................................................................................18 Spawning Site Selection .......................................................................................18 Spawning Behavior ................................................................................................19 General Behavior .............................................................................................................19 Fry and Juveniles (<10 cm) ....................................................................................20 Adults (>10 cm) ........................................................................................................20 iv Ecology of Bonytail and Razorback Sucker Razorback Sucker Life History ................................................................................................20 Physical Description .......................................................................................................21 Sexual Dimorphism ..........................................................................................................21 Distribution and Abundance ...........................................................................................22 Historic Distribution ................................................................................................22 Beginning of the End: 1880–1970 ..........................................................................22 1970 to Present ........................................................................................................22 Razorback Sucker Young ................................................................................................24 Diet ...............................................................................................................................24 Parasites ............................................................................................................................25 Age Determination ............................................................................................................26 Age-Length Distribution ..................................................................................................26 Longevity ............................................................................................................................27 Habitats and Habits ..........................................................................................................27 Movement .........................................................................................................................27 Reproduction ....................................................................................................................28 River Spawning .......................................................................................................29 Reservoir/Pond Spawning .....................................................................................31 Recruitment .............................................................................................................31 General Behavior ..............................................................................................................32 Larvae ......................................................................................................................32 Fry and Juveniles ....................................................................................................33 Adults ......................................................................................................................33 Eye “Blinking” .........................................................................................................33 Chapter 2. Complete Life Cycle of Two Endangered Fishes at Cibola High Levee Pond ...............35 Introduction .........................................................................................................................................35 History and Study Area .............................................................................................................35 Ecological Importance of Cibola High Levee Pond ..............................................................35 Water Quality Parameters ........................................................................................................37 Temperature ......................................................................................................................37 Dissolved Oxygen .............................................................................................................37 Conductance .....................................................................................................................37 Aquatic Community ...................................................................................................................37 Zooplankton ......................................................................................................................37 Fishes ........................................................