Pelagic Seabird Atlas, West Coast of Canada

The Atlas of Pelagic Seabirds off the West Coast of Canada presents maps that display the distribution of 48 species of seabirds and two species pairs (i.e., Red-necked and Red Phalaropes, and Hawaiian and Galapagos Petrels). Seabird surveys were conducted aboard commercial and Canadian federal government ‘ships-of-opportunity’ from 1982-1983 and 1991-2005 within the study area (45° N to 58° N and from the coast to 148° W). Sightings of rare species that came from other sources (including some pre 1982 and post 2005) are also included in order to present as complete a picture as possible.

For 33 species and one species pair, the average densities within 5’ latitude by 5’ longitude grid cells are displayed seasonally. The seabirds mapped in this manner include 11 species of Procellariiformes (albatrosses, fulmars, petrels, shearwaters and storm-petrels), and 24 species of Charadriiformes (phalaropes, skuas, gulls, terns and auks).

The sighting locations for an additional 15 species and one species pair are also mapped. This group, comprised of 10 species of Procellariiformes and seven species of Charadriiformes includes species that are relatively uncommon to rare in the study area (but previously documented); and species that are extremely rare and/or have not been documented and thus remain unconfirmed.

These data may be used to generate presence/absence and trends in and estimates of relative abundance. These data can also be used to examine patterns in temporal and spatial distribution. However, due to the opportunistic nature of the surveys, both in space and time, these data should not be used to determine absolute abundance.

The rationale for developing this atlas was the recognized need for a product that could assist with: coastal zone and conservation area planning; emergency response to environmental emergencies; and identification of areas of potential interactions between seabirds and anthropogenic activities. In addition, the data used to develop the document provides a baseline to compare with future seabird distributions in order to measure the impacts of shifts in composition, abundance and/or distribution of prey, and climatic and oceanographic changes.