IWDG Review of Code of Practice for the Protection of Marine Mammals during Acoustic Seafloor Surveys in Irish Waters

14th Apr 2010 The IWDG welcomed the introduction of the Code of Practice for the Protection of Marine Mammals during Acoustic Seafloor Surveys in Irish Waters and assisted in its development. At the time of publishing the NPWS committed to reviewing these guidelines after two years (August 2009).

In order to assist the NPWS in this review the IWDG have prepared this current document based on their experience of implementing the guidelines on a range of contracts delivered in Ireland.

A number of important issues have been addressed including the following main issues:

1. MMO must be dedicated solely to MMO work and have no other responsibility. The MMO should in addition preferably not be an employee of the exploration company or the seismic operator.

2. MMO should have a demonstratable knowledge of the Irish Mitigation regulations and knowledge of the cetacean species encountered in Irish waters.

3.The use of two MMOs is advised when daylight hours exceed 12 hours per day between April 1st and October 1st. If for any reason the MMO is not required to work full-time or for a very short duration then this need not apply.

4.The use of Passive Acoustic Monitoring (PAM) may be accepted as a mitigation measure but agreement as to its' use should be sought from the National Parks and Wildlife Service before commencement of the survey.

5.Once the sound source has achieved its maximum output (post soft start) it is not necessary to stop the survey should cetaceans approach the vessel. However prior to reaching maximum output should an animal be seen within the 1000 metres exclusion zone then operations must cease until 30 minutes (in waters up to 200m) or 60 minutes (waters deeper then 200m) after the animal was last seen within the exclusion zone.

6. Airgun tests may be required before a survey commences, or to test damaged or misfiring guns following repair, or to trial new arrays. Individual airguns, or the whole array may need testing, and the airguns may be tested at varying power levels. The following guidance is provided to clarify when a soft-start is required:

•If the intention is to test all airguns at full power then a 20 minute soft-start is required.

•If the intention is to test a single airgun on low power then a soft-start is not required.

•If the intention is to test a single airgun, or a number of guns on high power, the airgun or airguns should be fired at lower power first, and the power then increased to the level of the required test; this should be carried out over a time period proportional to the number of guns being tested and ideally not exceed 20 minutes in duration.

7. For seismic surveys line changes during night time or periods of poor visibility, when a visual check is not possible, it is preferable to reduce airgun output at the end of each line to an output of 150dB or to use the smallest airgun in the array (100 cubic inch gun or smaller). The increase from 150 dB to full power, prior to the start of the next line, should be undertaken in a stepped manner similar to a full soft start. The use of Passive Acoustic Monitoring should be considered when such visual checks are not possible.

Prepared by Patrick Lyne, IWDG MMO Co-ordinator

Dave Wall, IWDG Ship Survey Co-ordinator

Simon Berrow, IWDG Co-ordinator

A copy of the full review is available at:

For a copy of the report see Download the Full Report (PDF file, 89KB)