DFO spokeswoman Nicole Gallant said the seizures happened Friday night and Saturday morning. Four nets were seized in the Fraser Canyon, while the other was found near the Port Mann Bridge.
"Definitely it's frustrating, but the officers are encouraged by some lesser numbers every night," she said. "We're hoping that we'll see less and less as the week goes on."
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.
Despite the restrictions, Gallant says the DFO has pulled 55 nets and seized eight vessels so far. Officials have stepped up enforcement on the river, including night patrols and aerial units.
Twenty-seven people are being investigated and the DFO is also looking into complaints of illegal fish sales.
Poachers can face a fine of up to $100,000 or up to two years in jail if found guilty.