[Izumi]

Depends on where you are on the river. It is open all Year in NB4

Athabasca River
River
Open all year – Arctic Grayling limit 2 over 35 cm (limit 0 from Sept. 1 to Oct. 31); Mountain Whitefish limit 5 over 30 cm; Walleye limit 0 from Apr. 1 to May 31, and 3 over 43 cm from June 1 to Mar. 31; Pike limit 3 over 63 cm; Burbot limit 10; Goldeye limit 10.
Tribuatries except Clearwater and Hangingstone rivers
June 1 to Oct. 31 – Arctic Grayling limit 2 over 35 cm (limit 0 from Sept. 1 to Oct. 31); Walleye limit 3 over 43; Pike limit 3 over 63 cm; Mountain Whitefish limit 5 over 30 cm; Lake Whitefish limit 10; Burbot limit 10; Goldeye limit 10; Bait allowed.
Nov. 1 to May 31 – CLOSED

And the NSR is open all year in the PP2 area.

The RDR is closed for only a brief period in PP2 also.

Also there was another thread that was discussing the regs involved in ICE fishing flowing water and I believe it was only in the ES (Zone 1) areas where it was not allowed.