I thought we were over that sort of nonsense. Some of the more southerly pikeminnows were nearly destroyed due to elimination campaigns to protect trout from these "trash fish". Similar efforts have been conducted in the east against gar and bowfin. Their impacts on game fish are understudied and almost certainly overstated.
1st of all it was habitat destruction which wiped out most of the Colorado Pikeminnow (breeding areas)"The Colorado pikeminnow, P. lucius, is the largest member of the genus, averaging 4 to 9 pounds (2 to 4 kg) in adult fish with occasional specimens up to 25 pounds (11 kg). There are historical and anecdotal reports of Colorado pikeminnows nearing 6 feet (1.8 m) in length and 80 pounds (36 kg) in weight. The species is near extinction in its native Colorado River basin habitat, due to extensive habitat destruction." Wikipedia.
2nd of all the Northern Pikeminnow is such a threat to Salmon stocks because young Salmon colect at Damns
