Northern pike
Northern pike are also a problem in Holter Lake. The fish has long been present in small numbers in the lake, where it consumes more desirable native species like burbot, brown trout, and cuttrout trout. In March 2011, the Montana Department of Fish, Wildlife and Parks (FWP) set no limit on the number of northern pike anglers may take from Holter Lake and the waters just above it. A month later, the agency said it had completed an environmental assessment of a plan to remove northern pike from the Missouri River and its feeder streams. The agency sought public comment on the plan, which it said would take three to five years to complete at a cost of $20,000. The agency intended to use nets and "passive" fish traps to remove the pike, but might employ "active" measure like electric fishing, gill netting, or trap netting if the passive measures were not effective. In April 2011, the FWP removed all fishing limits on northern pike from the headwaters of the Missouri River to Holter Dam in order to encourage fishermen to eradicate the species. In March 2012, the state began a project to eradicate all northern pike from the headwaters of the Madison, Gallatin, and Jefferson rivers to Holter Dam on the Missouri River.