Science Response 2011/007

Adding a breakwater to the pilot wharf at Les Escoumins, Quebec: Potential impacts on marine mammals

Context

The Laurentian Pilotage Authority (LPA) is planning to build a sheet pile breakwater in the fall of 2011 in Anse-aux-Basques at Les Escoumins. The LPA is a federal Crown corporation whose mandate is to provide piloting services to vessels traveling on the St. Lawrence and the Saguenay Fjord in order to ensure safe navigation. The LPA has a transfer station at Les Escoumins, in Anse-aux-Basques, where their two pilot boats are moored. Having replaced one of its pilot boats, it has become necessary to build a structure to protect against the waves so as to ensure safe docking. In fact, waves are significant in Anse-aux-Basques and adding a breakwater to the existing wharf will reduce the risk of damaging the vessels and will facilitate operations.

The construction of a breakwater in Anse-aux-Basques is subject to a screening under the Canadian Environmental Assessment Act (CEAA), because the LPA is the proponent and Fisheries and Oceans Canada must issue an authorization pursuant to subsection 35(2) of the Fisheries Act (FA). The Fish Habitat Management Division (FHMD) has undertaken the project analysis under the FA and the Species at Risk Act (SARA) and, on August 2^nd, 2011, sought the cooperation of scientists from the Regional Science Branch, who have expertise on marine mammals in the St. Lawrence Estuary, to obtain their advice on the potential impacts on cetaceans, particularly species at risk, including the North Atlantic blue whale and the St. Lawrence beluga. Considering the short notice (advice required August 16^th, 2011 in order not to hinder the beginning of the work), a Science Special Response Process (SSRP) was initiated to provide scientific advice on three specific issues related to this project and its potential impacts on cetaceans:

1. Because no drilling or piling or sheet pile driving will occur between June and August, and a cetacean monitoring program will be implemented, will the sheet pile breakwater construction activities at Les Escoumins cause significant disturbance or major impacts on cetaceans?
2. If so, what additional mitigation measures should the proponent be required to introduce in order to reduce the disturbance and impacts?
3. If there are no measures to reduce the impacts, can we conclude that construction activities would only incidentally affect St. Lawrence beluga and Atlantic blue whale populations and that the following conditions would be met?
• All reasonable alternatives were considered and the best solution was adopted.
• All measures were taken to minimize the activity’s negative consequences.
• The activity will not jeopardize the survival or recovery of the species.

This Science response report stems from the meeting held on August 2^nd, 2011, under the SSRP on the review of potential impacts on marine mammals by the proposed construction of a breakwater at the Les Escoumins pilot wharf. Three experts in "underwater" acoustics and in marine mammal behaviour were present. A description of the main aspects of the project, timelines and proposed mitigation measures were presented for consideration in order to formulate this advice.

The proposed project to build a coastal breakwater in an area recognized as a unique habitat for marine mammals (Estuary and Marine Park MPA) has non-negligible risks of negative impacts on animals frequenting the area, including the species under SARA such as belugas and blue whales. This impact is felt through the propagation of noise associated with construction, particularly impulse noise from driving pilings and sheet piles. This strong impulse noise can cause permanent physical damage to the animals near the source. They alter the ambient noise over distances of several tens of km and impact the behaviour of animals, which has been shown, over at least 20 km.

Complete document (PDF, 61 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.