The physical characteristics of sound wave propagation in aquatic environments make it an efficient sensory cue for many aquatic organisms, providing a means for long-range directional perception. Since the industrial revolution, underwater acoustic environments have been significantly altered by human activities. Among these disturbances, shipping noise is the most widespread in both space and time, covering the broadest range of sound frequencies among anthropogenic noise sources.
In this presentation, we integrate laboratory-based behavioral data on the sound perception thresholds of two developmental stages of the giant scallop (Placopecten magellanicus), 1-year juveniles and 3-year adults, with a three-dimensional model that estimates marine traffic noise in the Gulf of Saint Lawrence, available on an annual scale with daily resolution (https://soundscape-atlas.uqar.ca). Our findings suggest that both juvenile and adult scallops experience an increase in valve movements triggered by navigation noise, affecting up to one-third of the scallop beds within our study area, particularly during late fall, winter, and early spring.
To quantify the energetic costs associated with these behavioral changes and their impacts on key physiological functions, we employed a Dynamic Energy Budget (DEB) model. This approach allowed us to estimate the energy expenditure due to increased valve movements, offering a deeper understanding of how shipping noise induced stress affects scallop health and population dynamics.
Building on these findings, combined with existing knowledge of giant scallop auto-ecology and acoustic modeling, we have mapped the risk areas for maritime traffic noise impacts on scallop fishing grounds in the Gulf of Saint Lawrence. These theoretical results lay the foundation for future in-situ experiments and will contribute to the development of management strategies aimed at protecting these ecologically and economically valuable marine ecosystems.