Timing Windows

NORTHWEST TERRITORIES IN-WATER CONSTRUCTION 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. During these periods, no in-water or shoreline work is allowed except under site-or project-specific review and with the implementation of protective measures. 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.

Timing windows are just one of many measures used to protect fish and fish habitat when carrying out a work or undertaking in or around water. Be sure to follow all of the measures outlined in the Operational Statements to avoid negative impacts to fish habitat.

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. Consult with local organizations such as hunters and trappers committees, Renewable Resource Councils or your local Fisheries and Oceans Canada (DFO) office.
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, in-water work (below the ordinary high water mark) is not permitted without site or project-specific review by DFO.

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 Whietfish	October-November	April-May (123-140 days)
Least Cisco	Late September to early October	May or June (break-up)
Arctic Cisco	Mid-Septmeber 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 In-water Activities are NOT Permitted, 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.

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