Assessing approaches for ship noise reduction within critical whale habitat.

Ship noise pollution significantly overlaps with critical habitats of endangered whales in the Santa Barbara Channel, prompting the need for effective noise reduction strategies. Various ship noise reduction approaches were assessed by simulating both source-centric (e.g., speed reduction or retrofit) and space-centric (e.g., routing changes) strategies to determine which would most effectively minimize noise within important marine habitats. Reducing the speeds of all ships achieved the highest noise reduction of the source-centric methods, although solely slowing cargo ships led to similar reductions. Implementing a single-route approach on the southern side of the Channel Islands achieved the greatest reduction of the space-centric strategies. For the multi-route approaches, some noise reduction was achieved by creating a buffer zone between the proposed shipping lanes and the critical habitat boundary. This simulation framework provides a mechanism for efficient exploration and assessment of noise reduction strategies across time and space. The framework can be updated to consider new approaches to changing ocean conditions.