As with the harbour seal monitoring, regular monitoring of the grey seal population is required to assess population trends and conservation status, as well as understanding factors that are driving the population trends. The grey seal population estimates are carried out during the pupping season in October from a Cessna airplane. All known pupping sites are visited 2-3 times and other potential areas are also scanned to detect new pupping sites. The number of pups at each site is counted directly by one observer and an assistant observer takes picture of the sites to subsequently count the number of pups from the photographs. An estimate of the total population size is then constructed by applying a correction factor to the number of observed pups.
Aerial censuses of grey seals in Iceland have been carried out at regular intervals since 1982. The population has decreased from an estimated 10.000 animals in 1982 to 4.200 in 2012, the most recent census. The management objective presented by the Icelandic government in 2006 states that the grey seal population should not decrease below 4.100 animals, and if that were to occur, measures should be taken. According to the latest population estimate, the grey seal population is now close to the recommended number. North Atlantic Marine Mammal Commission (NAMMCO) has advised that Iceland conduct more regular monitoring of the population and also recommend increased research on other ecological parameters regarding the Icelandic grey populations (see the project Grey seal population dynamics). The current aim is therefore to conduct aerial surveys to produce estimates for the size of the Icelandic grey seal population every other year. Increased monitoring of the population will create an important foundation for an improved management plan for the Icelandic population.
An aerial count was conducted late in 2017 and analysis is underway to establish a new population estimate for the Icelandic grey seal.