Timing Windows

ONTARIO IN-WATER CONSTRUCTION TIMING WINDOW GUIDELINES FOR THE PROTECTION OF FISH AND FISH HABITAT

Restricted activity 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.

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.

The timing windows in Table 1 identify periods when no in-water work is allowed, except with permission (see measure #5) and the implementation of protective measures.

Note that the restricted activity timing windows below only apply to projects completed using an Operational Statement. Timing windows identified on Conservation Authority permits, MNR work permits or DFO Fisheries Act authorizations may differ and take precedence.

How To Determine Timing Windows

1. Determine the fish species living in the water body where you wish to do work. Consult your Ontario Ministry of Natural Resources, Conservation Authority, Parks Canada (if the project is located within an area under its jurisdiction, including the Trent-Severn Waterway and Rideau Canal), or Fisheries and Oceans Canada (DFO) office.
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).
5. If the intended work cannot be conducted outside of the timing windows below, please contact your local Conservation Authority, DFO or Parks Canada office (if the project is located within an area under its jurisdiction), as appropriate, for other options.

Table 1: Restricted Activity timing windows for the protection of spawning fish and developing eggs and fry.
Dates represent the period of time when NO in-water work should occur. Regional boundaries are shown in Figure 1.

Spawning Period - Spring

Fish Species	Northwest Region	Northeast Region	Southern Region
Walleye	April 1 to June 20	April 1 to June 20	March 15 to May 31
Northern Pike	April 1 to June 15	April 1 to June 15	March 15 to May 31
Lake Sturgeon	May 1 to June 30	May 1 to July 15	May 1 to June 30
Muskellunge	May 1 to July 15	May 15 to July 15	March 15 to May 31
Large/ Smallmouth Bass	May 15 to July 15	May 15 to July 15	May 1 to July 15
Rainbow Trout	April 1 to June 15	April 1 to June 15	March 15 to June 15
Other/Unknown Spring Spawning Species	April 1 to June 15	April 1 to June 15	March 15 to July 15

Spawning Period - Fall

Fish Species	Northwest Region	Northeast Region	Southern Region
Lake Trout	September 1 to May 31	September 1 to May 31	October 1 to May 31
Brook Trout	September 1 to June 15	September 1 to June 15	October 1 to May 31
Pacific Salmon	September 1 to June 15	September 1 to June 15	September 15 to May 31
Lake Whitefish	September 15 to May 31	September 15 to May 15	October 15 to May 31
Lake Herring	October 1 to May 31	October 1 to May 31	October 15 to May 31
Other/Unknown Fall Spawning Species	September 1 to June 15	September 1 to June 15	October 1 to May 31

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