The Salish Sea, an area of complex oceanography and bathymetry, supports a number of
apex cetacean species. In the last decade, anomalous sightings of cetaceans have become more
frequent and shifts in species abundance have occurred. This 2014 Pelagic Ecosystem Function
(PEF) study, using large and fine scale surveys in the San Juan Channel (SJC), determined that
cetacean mean density was unusually low but species composition was more diverse than
previous years, perhaps due to anonymously warm surface water. The relationship between tides,
bathymetry and harbor porpoise abundance at small scales were different than those found
previously in the region
