Research Document - 2006/067

2005 Pup Production of Hooded Seals, Cystophora cristata, in the Northwest Atlantic

By Stenson, G.B., M.O. Hammill, J. Lawson and J.F. Gosselin

Abstract

Photographic and visual aerial surveys to determine current pup production of Northwest Atlantic hooded seals (Cystophora cristata) were conducted off Newfoundland, in the Gulf of St. Lawrence in March 2004, and off Newfoundland, in the Gulf and in Davis Strait during 2005. Surveys in the Gulf and Front were corrected for the temporal distribution of births and the mis-identification of pups by readers. In 2004, pup production at the Front was estimated to be 123,862 (SE = 18,640, CV = 0.150). Pup production in the Gulf was estimated to be 1,388 (SE = 298, CV = 0.216) although this is considered to be negatively biased. In 2005, pup production at the Front was estimated to be 107,013 (SE = 7,558, CV = 0.071) while 6,620 (SE = 1,700, CV = 0.258) pups were estimated to have been born in the Gulf. Pup production in the Davis Strait whelping concentration was estimated to be 3,346 (SE = 2,237, CV = 0.668). Combing these areas resulted in an estimated pup production in the three northwest Atlantic whelping areas of 116,900 (SE = 7,918, CV = 6.8%). Comparison with previous estimates suggests that pup production may have increased since the mid 1980s. However, understanding if abundance has changed is hampered by our lack of understanding of the relationship among whelping areas.

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