The Salish Sea is critical habitat for several whale species including the humpback whale (Megaptera novaeangliae). Boundary Pass is part of the Salish Sea and connects the Pacific Ocean to several commercial shipping ports in the Pacific Northwest Region of North America. Since 1997, the number of Humpback whales continues to increase in this area, meanwhile the number of vessels is also increasing such that Boundary Pass is among the busiest shipping routes in the region. This high vessel traffic in the area leads to acoustic disturbances that degrades whale foraging opportunities for humpback whales. Commercial vessels transporting goods through whale habitat causes an increased risk of vessel collisions with humpback whales. Humpback-whale movements in Boundary Pass was recorded through systematic scan surveys conduction from a vantage point between June and August. Whale occupancy was compared to oceanographic variables and vessel presence. We found humpback whales were most likely to be present during ebb tides of speeds of -2 m/s under the influence of low tides and also whales were active in areas overlap with shipping lane in the area. Based on our founding in the area about humpback whale connection with biophysical properties of region I hypothesized that whale distribution in area and it relation to low tide and ebb current is most probably under the influence of food abundance in those periods of time. This study concludes with policy recommendations for improving humpback whale foraging grounds by reducing acoustic harassment and risk of ship strikes in the Boundary Pass.
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Thesis advisor: Joy, Ruth
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