The Bull Frogs have proliferated from downstream. I had seen a lot of bull frogs many years ago down in the forest of Cottonwoods in the Mohave Narrows area by Spring Valley Lake. I think they came from that area when the Mohave River was running giving them a route to go upstream, through the Mohave Forks Dam then up Deep Creek, or perhaps they came from the West Fork of the Mohave, Rancho Las Flores area where there are marshes and waterways which would be great habitat for them if introduced. I had never seen one in the Deep Creek before, but then one afternoon I heard the deep croak of one down stream from DCHS near the Rainbow bridge area about 7 years ago. Since that time they have been steadily moving upstream and last year I found the big full frog tadpoles as far upstream as Coxey Creek where it meets Deep Creek, and I would guess they are even further upstream than that. They eat anything they can fit down their mouths and are superbly designed for survival. Nothing will get them out Deep Creek now that they are in there. I have seen pools with literally hundreds of bull frog poliwogs in them. I have also noticed in the same time frame a disappearance of the once abundant grey tree frogs that use to be all along the creek. Easy prey for the bigger and more aggressive bull frogs.