Abundance and Distribution of Cetaceans in Canadian Pacific Waters in 2018

Abstract

The Pacific Region International Survey of Marine Megafauna (PRISMM) was a multi species, ship-based, systematic line transect survey conducted between July 4 and September 5, 2018 to estimate the abundance and distribution of cetacean species in Canadian Pacific waters. Over 2,000 sightings were made of 20 marine mammal species along 8,400 km of effort. Density and abundance were estimated for nine species using either standard line transect analyses or density surface modelling. Maps of predicted distribution were produced for the most commonly-encountered species (Humpback Whales, Fin Whales, Dall’s and Harbour Porpoises). Once corrected for diving behaviour, abundance was estimated at 24,300 Dall’s Porpoises (95%CI 19,500–30,300), 12,200 Humpback Whales (8,200–18,300), 7,400 Harbour Porpoises (3,600–15,200), 5,900 Pacific White-sided Dolphins (2,900–11,800), 3,000 Fin Whales (2,200–4,000), 2,200 Northern Right Whale Dolphins (730–6,700), 920 Risso’s Dolphins (180–4,800), 200 Blue Whales (59–670), and 70 Sei Whales (24–210). These estimates represent the abundance of cetaceans in Canadian waters at the time of the survey but do not reflect the abundance of entire populations, which are distributed across wider areas of the Pacific.