The Legault government must decide this year whether to authorize two recurring dredging and sediment disposal projects in a sector of critical beluga habitat that should be part of the expansion of the Saguenay–St. Lawrence Marine Park. However, there are no scientific studies to assess the impacts of these operations on this increasingly endangered species, learned The duty.
The Société port du Bas-Saint-Laurent et de la Gaspésie (SPBSG) recently submitted the impact study for its sediment dredging project in the port of Gros-Cacouna for the next decade. It is a question of dredging up to 60,000 cubic meters of sediment every three years, in order to maintain the depth of water necessary for the commercial vessels which dock at the wharf. Sediment loaded onto a barge will then be discharged further offshore. Up to 475 trips are expected over approximately one month, with work scheduled around the clock.
The problem is that this dredging and disposal work will take place directly in the “critical habitat” of the beluga, and more specifically in a sensitive area for females and young, since it is considered a nursery for the species. The impact study also specifies that “the Cacouna sector is highly frequented by beluga populations (species at risk) and [que] these are sensitive to the increase in suspended solids, noise levels and maritime traffic linked to the movements of the barge/dredge towards the discharge site in open water”.
These animals, which are vulnerable to noise pollution and disturbance, should also be exposed to another, more intensive dredging project, which will take place not far from there, in Rivière-du-Loup. In this case, the Société des traversiers du Québec (STQ) plans to dredge 60,000 m3 sediment. Work is also planned 24 hours a day, with 15 to 30 barge trips to the discharge site located in the estuary, for a total of 475 discharges each year.
” Reduction measures “
This project, which is a continuation of the work of past years, has already been analyzed by a commission from the Bureau d’audiences publiques sur l’environnement (BAPE). The report concludes that the project is necessary to maintain the ferry service between Rivière-du-Loup and Saint-Siméon. The commissioners also consider that it “does not present a major issue”, in particular because of the planned “mitigation measures” and the monitoring program for the presence of belugas during the work.
In Gros-Cacouna and Rivière-du-Loup, the proponents say they will monitor the animals during transport of sediment and during open water disposal. To achieve this, visual monitoring and the use of hydrophones, devices that capture the sounds emitted by belugas, are planned. “A supervisor experienced in the acoustic monitoring of marine mammals will supervise the monitoring”, specifies the impact study of the SPBSG.
If a beluga approaches within a radius of less than 400 meters, we guarantee that the work will be stopped. For example, the STQ calculated 28 hours of stoppage in 2020, out of the 760 hours of work, according to a report submitted to Fisheries and Oceans Canada (DFO). Regarding these data, the ministry specifies that “qualified observers note the presence of belugas almost every day inside the exclusion zone [de 400 mètres] or beyond”.
In both cases, the work is also scheduled for the fall, outside the period of “high traffic” in the sector. According to what DFO argues for the case of Rivière-du-Loup, “this period represents a compromise to allow the dredging necessary to maintain the service of the crossing, while protecting the beluga. However, it could change with the evolution of knowledge”.
How many belugas are there in the region at this time of year? DFO was unable to provide us with data, stating that a report is in preparation and that it should be completed by the fall of 2023. The federal department simply mentions “a frequency of occurrence smaller” in the fall than in the spring.
This does not mean that the work planned at the two ports, with the discharge of sediment into an important habitat for female belugas and their young, is without risk. DFO specifies in particular that “the noise propagates effectively in the water, which would make dredging activities perceptible to belugas over distances of several kilometres”.
The SPBSG impact study also indicates that “the noise from open water discharge activities can have a direct effect on marine mammals by causing them to avoid the site or, indirectly, by avoiding the site by their prey . The sound of boats transporting sediment to the disposal site can also have an impact on marine mammals”. These behaviors of avoidance or flight from this sector “could have repercussions on the feeding, reproduction and movement of marine mammals, including the beluga”.
No studying
However, despite the identification of many risks for a protected species that continues to decline, DFO confirms the absence of scientific studies on the subject. “There are indeed no studies, from the department or other organizations, that specifically document the effects of dredging on belugas in the St. Lawrence. Data on other species elsewhere in the world are sparse and, at best, very fragmentary,” a written response states.
In their report on the STQ dredging project in Rivière-du-Loup, the BAPE commissioners consider that “only a study of the cumulative effects on belugas in the St. Rivière-du-Loup, carried out jointly by the Ministère des Forêts, de la Faune et des Parcs and by Fisheries and Oceans Canada, would make it possible to assess the contribution of dredging in relation to other human activities taking place in the sector”.
The Ministry of the Environment, the Fight against Climate Change, Wildlife and Parks (MELCCFP), specifies that the Legault government has not yet given the green light to the STQ dredging project. He is currently completing the “environmental acceptability analysis”, and a “recommendation” will then be sent to Minister Benoit Charette. As for the Gros-Cacouna project, the impact study has not yet been deemed admissible by the MELCCFP. Once this is the case, a “public information period” is planned, during which citizens can request that a BAPE be held.
Scientific Director of the Group for Research and Education on Marine Mammals (GREMM), Robert Michaud calls for the greatest caution. “Physical and acoustic disturbance is still considered one of the main factors likely to hinder the recovery of belugas. In addition, disturbance, whether physical or acoustic, is one of the factors on which we can act effectively and quickly. Any project likely to increase physical or acoustic disturbance in critical beluga whale habitat must be carefully examined,” he explains.
In the case of these two projects, it is quite possible that at least the portion of the sediment discharges will take place in an area that will be added to the Saguenay–St. Lawrence Marine Park, once the expansion project desired by Quebec and Ottawa will be finished. When announcing this project on March 10, Minister Benoit Charette stressed his desire to “improve the protection of marine mammals living in the St. Lawrence estuary, such as the beluga, which is a species emblematic of the fragility of this habitat.