Northwest Territories Restricted Activity Timing Windows for the Protection of Fish and Fish Habitat

Restricted activity timing windows have been identified for Northwest Territories lakes, rivers and streams to protect fish during spawning and incubation periods when spawning fish, eggs and fry are vulnerable to disturbance or sediment. Restricted activity periods are determined on a case by case basis according to the species of fish in the water body, whether those fish spawn in the spring, summer, fall or winter, and where the water body is located.

Regional Map
Figure 1: Fish Timing Zones for the Northwest Territories.

How To Determine Timing Windows

  1. Determine the fish species living in the water body where you wish to do work.
  2. Determine if the fish living in the water body spawn in the spring, summer, fall or winter according to Table 1. There may be one or more spawning types in any given water body. For most water bodies in the NWT there are at least two spawning types. The spawning windows for multiple species should be observed.
  3. Determine if the water body is in Zone 1, 2 or 3 according to Figure 1.
  4. Using Tables 2 and 3, determine the in-water work timing restrictions according to the location of a water body (Zone 1, 2 or 3) and the type (spring/summer, fall or winter) of spawning fish. During these periods work should be avoided.
Table 1: General Range of Spawning Times in Northwest Territories.
Fall Spawners
Species Range of Spawning Timing Incubation/
Hatch Time
Lake Whitefish Mid-September to mid-October Late winter-
early spring
Broad Whitefish November April-May
Round Whitefish October-November April-May 
(123-140 days)
Least Cisco Late September to early October May or June
(break-up)
Arctic Cisco Mid-September to early October Spring under ice
Lake Cisco September to November Spring
Inconnu Late September to early October Spring
Lake Trout Mid to late August May-June
Bull Trout Mid-August to October Spring 
(around break-up)
Dolly Varden Char September to early October 
(Rat River - 
August 15 to late September)
8 months 
(May or June)
Arctic Char Late September to early October April
Chum Salmon September to October 122-173 days

Spring/Summer Spawners
Species Range of
Spawning
Timing
Incubation/
Hatch Time
Arctic Grayling Mid-May to early June 8-32 days
Northern Pike Early May to mid-June Approximately 2 weeks
Walleye April-June 4-34 days
Yellow Perch March-July 8-20 days
Goldeye Early May to early July Approximately 2 weeks
Rainbow Smelt April-May About 29 days
Longnose Sucker June Approximately 2 weeks
White Sucker June Approximately 2 weeks

Winter Spawners
Species Range of
Spawning
Timing
Incubation/
Hatch Time
Burbot December to mid-January 30 days to 3 months

Table 2: Timing Windows when work should be avoided, by Type of Spawning.
Zone Spring/
Summer
Fall Winter
NWT Zone 1 April 1 to July 15 September 15 ¹ ² to June 30 December 1 to April 15
NWT (SW corner)
Zone 2
April 1 to July 15 August 15 to June 30 December 1 to April 15
NWT offshore
islands Zone 3
N/A September 15 ¹ to June 30 N/A

Notes: ¹ For lakes with spawning Lake Trout populations, the timing window begins earlier, starting August 15.
  ² Dolly Varden in the Rat River begin spawning in mid-August and therefore the fall window for this system should be August 15 to June 30.

Timing Windows for Water bodies Where All Spawning Types are Present or Fish Species NOT Known: If all spawning types are present, or if you don't know which species are in the water body, then Table 3 can be followed.

Table 3: Fish Timing Windows using All Spawning Types.
Zone When In-water Activity
Not Permitted
When In-water
Activity May Occur
NWT Zone 1 September 15 to July 15 ¹ ² July 16 to September 14 ³
NWT Zone 2 August 15 to July 15 July 16 to August 14
NWT Zone 3 September 15 to June 30 ¹ July 1 to September 14


Notes: ¹ For lakes with spawning Lake Trout populations, the timing window begins earlier, starting August 15.
  ² Dolly Varden in the Rat River begin spawning in mid-August and therefore the fall window for this system should be August 15 to June 30.
  ³ For the Rat River and for lakes with spawning Lake Trout populations, the timing window when in-water activities may occur is July 16 to August 14.