Executive Summary
This study uses acoustic vector sensing (AVS) to monitor blue and fin whale habitat occupancy off Central California, revealing interannual shifts in their distributions. Blue whales showed increased occupancy of offshore deep-water habitats, correlating with stronger upwelling and krill abundance. This shift heightened their exposure to ship strike risk in shipping fairways.
Why It Matters
Understanding marine mammal distribution and their exposure to anthropogenic threats, especially in strategically important maritime regions, is crucial for naval operations, maritime security, and environmental policy.
Key Takeaways
- Acoustic Vector Sensing (AVS) effectively monitors whale habitat occupancy and behavior over large marine areas.
Source evidence · PDF page 2
Acoustic vector sensing (AVS) of the powerful calls produced by baleen whales enables continuous monitoring over large areas with spatial information contained in the bearing estimates to whales.
- Blue whale habitat shifted towards offshore deep-water areas, increasing their spatial overlap with shipping fairways.
Source evidence · PDF page 5
Shifts in blue whale habitat occupancy into ODW habitat (Figs. 3, 4) imply consequences for the exposure of an endangered species to a key anthropogenic threat. Examining 515 days of substantial daily detection (Fig. 5a), we consider interannual variation in blue whale exposure to ship strike risk [27].
- This habitat expansion significantly increased blue whales' exposure to ship strike risk, a major anthropogenic threat.
Source evidence · PDF page 7
In contrast, blue whale exposure to ship strike risk in this study region may be exacerbated under conditions of habitat expansion, to which the whales respond by foraging more in offshore habitat that is transected by shipping fairways.
Strategic Relevance
The study highlights the utility of advanced acoustic sensing for environmental monitoring in critical maritime zones, which can inform naval operations, maritime domain awareness, and environmental regulations impacting shipping lanes.