Fisheries and Oceans Canada has now seized a total of 60 nets and nine vessels, said spokeswoman Nicole Gallant.
Earlier this month, commercial and recreational fisheries were forced to close in order to conserve this year's dwindling salmon numbers.
Salmon fishing was banned on a section of the Fraser River from the CPR bridge at Mission, B.C., to the Alexandra Bridge, north of Hope.
On Friday night and Saturday morning, five nets were seized in the Fraser Canyon and near the Port Mann Bridge as officials step up enforcement on the river, including night patrols and aerial units.
Gallant says anyone who sees suspicious activity on the Fraser should contact the DFO, and reminds the public that purchasing fish caught in the closed area is forbidden.