To estimate Grey Seal (Halichoerus grypus) pup production, photographic aerial surveys were conducted of the major Grey Seal breeding colonies in Canadian waters. The last survey was completed in January 2021. A total of 72,209 pups were counted on digital imagery from Sable Island, the largest breeding colony. Reconnaissance flights found no new colonies along the Atlantic coast of Nova Scotia and New Brunswick. Pup developmental stage surveys were undertaken on the ground or from helicopter at the seven largest breeding colonies to describe the birth distribution and correct the pup count for the estimate of pups born after the aerial photographic survey. The estimated number of pups born on Sable Island was 76,600 (SE = 2,900) and for Coastal Nova Scotia was 4,700 (SE = 550). For Sable Island, this is the first estimate of pup production since the 1960s that has not been a significant increase. Sable Island accounts for 77.5% of total pup production in Canada, and the change in trend in pup production on Sable Island is reflected in the trend in total pup production. Pup production in the Gulf of St. Lawrence continues to fluctuate with little evidence of trend over the past several decades, while at the more recently-established breeding colonies in southwest Nova Scotia, pup production continues to increase.

In February 2026, the time series of grey seal pup production estimates for Maritimes Region was made open source. The open data was set up with no abbreviations or codes and restricted to just Maritimes Region. Notably there are counts in the dataset provided not linked to specific breeding colonies, for the miscellaneous locations the latitude and longitude are for roughly center of the colonies or region.

Cite this data as: den Heyer., C. Data of Grey Seal Pup Production in Canadian Water. Published: April 2026. Ocean Ecosystems Science Division, Maritimes Region, Fisheries and Oceans Canada, Dartmouth NS. https://open.canada.ca/data/en/dataset/ea8962b2-0d75-4500-a3de-d631a1e5308f