Estimation of hooded seal (Cystophora cristata) pup production in the Greenland Sea pack ice during the 2005 whelping season

In March 2005 aerial surveys were carried out to estimate pup production of Greenland Sea hooded seals, Cystophora cristata in three whelping patches using photographic strip transects. The majority of whelping occurred 17–23 March and surveys were carried out on 24 March. The temporal distribution of births and estimated proportion of solitary bluebacks present within the survey area were used to correct the abundance estimates. The total estimated pup production (15,250 pups, s.e. = 3,470; CV = 22.8%) was lower than an estimate from a comparable study in 1997. The current estimate is considered to be negatively biased, as it is uncorrected for pups born outside the whelping concentrations. Population modeling suggests a substantial decline with subsequent stabilization at a lower level for Greenland Sea hooded seals in recent decades. It is suggested that future research on the population explore possible factors (e.g. reduced fertility, predation, food shortage, disease, reductions in ice cover) that may have contributed to the apparent prevailing low abundance.