The Saguenay Fjord cuts 105 kilometres inland from the St. Lawrence estuary, its cliffs rising 350 metres above waters that plunge to 275 metres depth. Carved by glaciers during the last ice age, the fjord remains one of the longest and deepest in eastern North America. At its mouth lies Tadoussac, a village founded in 1599 as New France's first fur-trading post, where Indigenous Innu communities had gathered for millennia to hunt beluga whales in the nutrient-rich confluence. The meeting of cold Saguenay currents and warmer St. Lawrence waters creates an upwelling zone that sustains North America's southernmost beluga population. Between May and October, thirteen cetacean species—minke, fin, blue, and humpback whales among them—feed on krill swarms that bloom in the oxygen-rich churn. The beluga pod, numbering approximately 900 individuals, remains resident year-round, distinguished by their ghostly white colouration and vocal echolocation clicks audible to surface observers. Established in 1998, Saguenay–St. Lawrence Marine Park protects 1,245 square kilometres of this convergence zone under federal and provincial jurisdiction. Saguenay fjord cruise Tadoussac departures operate from the village's sheltered bay, where the crimson-roofed Tadoussac Hotel has anchored the waterfront since 1864. Zodiac vessels carry twelve passengers at water level, their rigid-hull inflatables designed for speed and manoeuvrability during whale approaches. Full-size cruisers accommodate up to 400 guests across three decks, offering heated cabins and naturalist-led commentary. Both vessel types adhere to Marine Mammal Regulations enforced within the park—maintaining 400-metre distances from endangered species, 200 metres from belugas, and 100 metres from other cetaceans. Tadoussac boat tours navigate the fjord's first twenty kilometres, where granite walls display horizontal sediment bands left by ancient seabeds. Peregrine falcons nest in cliff crevices. Grey seals haul out on tidal rocks near Pointe-Noire. The protected waters extend southwest to Baie Sainte-Marguerite, where beluga mothers calve in shallow, predator-free bays each June. Research stations operated by the Group for Research and Education on Marine Mammals monitor population health through photo-identification catalogues dating to 1982, documenting individual whales by dorsal scars and pigmentation patterns across four decades of observation.