Ontario Restricted Activity Timing Windows for the Protection of Fish and Fish Habitat

Restricted activity timing windows are applied to protect fish from impacts of works or undertakings in and around water during spawning migrations and other critical life history stages. In Ontario, the Ministry of Natural Resources (MNR) has the responsibility for setting timing window guidelines. These guidelines 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 or fall, and whether the water body is located in the Northwest, Northeast or Southern Region of Ontario.

Figure 1: Ontario's Northwest, Northeast and Southern Region boundaries for determining application of restricted activity timing windows.

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 water body is located in the Northwest, Northeast or Southern Region of Ontario according to Figure 1.
3. Use Table 1 to determine the in-water restricted activity timing windows according to the location of the waterbody and all of the species of fish found within that waterbody (spring or fall spawners).
4. For water bodies with more than one species, the most restrictive timing windows should be combined for all species present (e.g. for a water body with both walleye and bass in Southern Region, the combined timing window should be: Mar. 15 to July 15).

Table 1: Restricted Activity timing windows for the protection of spawning fish and developing eggs and fry.
Dates represent when work should be avoided. Regional boundaries are shown in Figure 1.