Statement of Canadian Practice with respect to the Mitigation of Seismic Sound in the Marine Environment

• Complete Text
• Introduction
• Background Paper
• Context
• Definitions
• Application
• Poster

Application

1. Unless otherwise provided, the mitigation measures set out in this Statement apply to all seismic surveys planned to be conducted in Canadian marine waters and which propose to use an air source array(s).
2. The mitigation measures set out in this Statement do not apply to seismic surveys conducted:
   1. on ice-covered marine waters; or
   2. in lakes or the non-estuarine portions of rivers.

Planning Seismic Surveys

Mitigation Measures

3. Each seismic survey must be planned to
   1. use the minimum amount of energy necessary to achieve operational objectives;
   2. minimize the proportion of the energy that propagates horizontally; and
   3. minimize the amount of energy at frequencies above those necessary for the purpose of the survey.
4. All seismic surveys must be planned to avoid:
   1. a significant adverse effect for an individual marine mammal or sea turtle of a species listed as endangered or threatened on Schedule 1 of the Species at Risk Act; and
   2. a significant adverse population-level effect for any other marine species.
5. Each seismic survey must be planned to avoid:
   1. displacing an individual marine mammal or sea turtle of a species listed as endangered or threatened on Schedule 1 of the Species at Risk Act from breeding, feeding or nursing;
   2. diverting an individual migrating marine mammal or sea turtle of a species listed as endangered or threatened on Schedule 1 of the Species at Risk Act from a known migration route or corridor;
   3. dispersing aggregations of spawning fish from a known spawning area;
   4. displacing a group of breeding, feeding or nursing marine mammals, if it is known there are no alternate areas available to those marine mammals for those activities, or that if by using those alternate areas, those marine mammals would incur significant adverse effects; and
   5. diverting aggregations of fish or groups of marine mammals from known migration routes or corridors if it is known there are no alternate migration routes or corridors, or that if by using those alternate migration routes or corridors, the group of marine mammals or aggregations of fish would incur significant adverse effects.

Safety Zone and Start-up

Mitigation Measures

6. Each seismic survey must:
   1. establish a safety zone which is a circle with a radius of at least 500 metres as measured from the centre of the air source array(s); and
   2. for all times the safety zone is visible,
      1. a qualified Marine Mammal Observer must continuously observe the safety zone for a minimum period of 30 minutes prior to the start up of the air source array(s), and
      2. maintain a regular watch of the safety zone at all other times if the proposed seismic survey is of a power that it would meet a threshold requirement for an assessment under the Canadian Environmental Assessment Act, regardless of whether the Act applies.
7. If the full extent of the safety zone is visible, before starting or restarting an air source array(s) after they have been shut-down for more than 30 minutes, the following conditions and processes apply:
   1. none of the following have been observed by the Marine Mammal Observer within the safety zone for at least 30 minutes:
      1. a cetacean or sea turtle,
      2. a marine mammal listed as endangered or threatened on Schedule 1 of the Species at Risk Act, or
      3. based on the considerations set out in sub-section 4(b), any other marine mammal that has been identified in an environmental assessment process as a species for which there could be significant adverse effects; and
   2. a gradual ramp-up of the air source array(s) over a minimum of a 20 minute period beginning with the activation of a single source element of the air source array(s), preferably the smallest source element in terms of energy output and a gradual activation of additional source elements of the air source array(s) until the operating level is obtained.

Shut-down of Air Source Array(s)

Mitigation Measures

8. The air source array(s) must be shut down immediately if any of the following is observed by the Marine Mammal Observer in the safety zone:
   1. a marine mammal or sea turtle listed as endangered or threatened on Schedule 1 of theSpecies at Risk Act; or
   2. based on the considerations set out in sub-section 4(b), any other marine mammal or sea turtle that has been identified in an environmental assessment process as a species for which there could be significant adverse effects.

Line Changes and Maintenance Shut-downs

Mitigation Measures

9. When seismic surveying (data collection) ceases during line changes, for maintenance or for other operational reasons, the air source array(s) must be:
   1. shut down completely; or
   2. reduced to a single source element.
10. If the air source array(s) is reduced to a single source element as per subsection 9(b), then:
    1. visual monitoring of the safety zone as set out in section 6 and shut-down requirements as set out in section 8 must be maintained; but
    2. ramp-up procedures as set out in section 7 will not be required when seismic surveying resumes.

Operations in Low Visibility

Mitigation Measures

11. Under the conditions set out in this section, cetacean detection technology, such as Passive Acoustic Monitoring, must be used prior to ramp-up for the same time period as for visual monitoring set out in section 6. Those conditions are as follows:
    1. the full extent of the safety zone is not visible; and
    2. the seismic survey is in an area that
       1. has been identified as critical habitat for a vocalizing cetacean listed as endangered or threatened on Schedule 1 of the Species at Risk Act, or
       2. in keeping with the considerations set out in sub-section 4(b), has been identified through an environmental assessment process as an area where a vocalising cetacean is expected to be encountered if that vocalizing cetacean has been identified through the environmental assessment process as a species for which there could be significant adverse effects.
12. If Passive Acoustic Monitoring or similar cetacean detection technology is used in accordance with the provision of section 11, unless the species can be identified by vocal signature or other recognition criteria:
    1. all non-identified cetacean vocalizations must be assumed to be those of whales named in sections 8(a) or (b); and
    2. unless it can be determined that the cetacean(s) is outside the safety zone, the ramp-up must not commence until non-identified cetacean vocalizations have not been detected for a period of at least 30 minutes.

Additional Mitigative Measures and Modifications

Mitigation Measures

13. Persons wishing to conduct seismic surveys in Canadian marine waters may be required to put in place additional or modified environmental mitigation measures, including modifications to the area of the safety zone and/or other measures as identified in the environmental assessment of the project to address:
    1. the potential for chronic or cumulative adverse environmental effects of
       1. multiple air source arrays (e.g., two vessels on one project; multiple projects), or
       2. seismic surveys being carried out in combination with other activities adverse to marine environmental quality in the area affected by the proposed program or programs;
    2. variations in sound propagation levels within the water column, including factors such as seabed, geomorphologic, and oceanographic characteristics that affect sound propagation;
    3. sound levels from air source array(s) that are significantly lower or higher than average; and
    4. species identified in an environmental assessment process for which there is concern, including those described in sub-section 4b).
14. Variations to some or all of the measures set out in this Statement may be allowed provided the alternate mitigation or precautionary measures will achieve an equivalent or greater level of environmental protection to address the matters outlined in sections 6 through 13 inclusive. Where alternative methods or technologies are proposed, they should be evaluated as part of the environmental assessment of the project.
15. Where a single source element is used and the ramping up from an individual air source element to multiple elements is not applicable, the sound should still be introduced gradually whenever technically feasible.