Grey seal

Updated: May 2020

The grey seal (Halichoerus grypus) is a coastal or continental shelf marine mammal species, inhabiting the temperate areas of the North Atlantic. Grey seals haul out on exposed reefs or on beaches of undisturbed islands. They are relatively large, around 2m in length and 200-400kg in weight, with males larger than females. Besides the difference in size between the two genders, there are differences in shape as well. The snout of the adult male is elongated with a convex outline giving it an appearance like a horse head. The body colour of the adults may vary from entirely black to almost creamy-white, with males tending to be darker than females.


Roughly 650,000, with the largest numbers on the east coasts of Canada and USA


Temperate waters of the North Atlantic


Small numbers taken mainly for skin, although meat and blubber are also used.


Management is the responsibility of the countries. The NAMMCO Coastal Seals Working Group provides scientific advice on stock status and sustainable takes.

In the most recent assessment (2016) the species is listed as ‘Least Concern’ on the global IUCN Red List as well as on the Norwegian national red list. It is listed as ‘Vulnerable’ on the Icelandic national red list as of 2018.

© Amy Bishop

© Pixabay

Scientific name: Halichoerus grypus

Faroese: Láturkópur
Greenlandic: Sigguttooq
Icelandic: Útselur
Norwegian: Havert, gråsel

Danish: Gråsæl
English: Grey seal, gray seal


35-40 years


One pup per year, age at maturity 5-7 years


Generalists feeding on a wide variety of prey usually near the sea bottom (demersal and benthic fish)


2m in length and 200-400kg in weight, with males larger than females

© Amy Bishop

General Characteristics

The grey seal (Halichoerus grypus) is a coastal or continental shelf marine mammal species, inhabiting the temperate areas of the North Atlantic. Grey seals haul out on exposed reefs or on beaches of undisturbed islands. They are relatively large, around 2m in length and 200-400kg in weight, with males larger than females. Besides the difference in size between the two genders, there are differences in shape as well. The snout of the adult male is elongated with a convex outline giving it an appearance like a horse head. The body colour of the adults may vary from entirely black to almost creamy-white, with males tending to be darker than females.


© Amy Bishop

Breeding occurs on islands, isolated beaches or on the pack ice. The grey seal starts breeding in late September with its maximum activity in October/November and continues until February/March. The gestation period of the female Grey seal is 11.5 months, including a 3-month delay in the implantation of the fertilised egg. Grey seals give birth to a single pup, in the autumn. Pups are born in a silky white fur which is moulted by the end of the lactation period, which lasts about 15-20 days. Pupping sites are usually on isolated skerries or uninhabited islands. In Canada, and also in the Baltic, spring-breeding seals may give birth on sea ice as well (NAMMCO 2016c).

Molting grey seal pup © Sandra Granquist


Grey seals are generalist predators, consuming a wide variety of species. Their diet varies seasonally and geographically, but the species is considered as largely demersal or benthic feeders (Bowen et al. 1993).

The grey seal is a large consumer of sandeel (Ammodites spp.), which at times can be over 50% of their diet (Bowen and Harrison 1994, Hammond et al. 1994, Beck et al. 2007). In Canada sandeels and redfish (Sebastes sp.) together accounted for 40-91% of the diet (Bowen and Harrison 1994). Atlantic Cod can be an important part of the diet in some areas and seasons (Hammill et al. 2014). There is ongoing debate about the possible negative impacts of seal predation on certain groundfish populations. One factor contributing to this debate is the growth in grey seal populations in eastern Canadian waters over the past five decades and the concurrent decline, or in some cases collapse, of several groundfish populations in the 1990s (Hammill et al. 2014, Link 1).

In the Eastern Atlantic Stock, the most important prey are gadids, sandeel and wolffish (Anarchichus spp.) (Prime & Hammond 1990, Hauksson and Bogason 1997, Mikkelsen et al. 2002). In the Outer Hebrides, UK, gadids account for 40% or more of the diet, sandeels are less important in this area (Hammond et al. 1994).

Atlantic cod
Atlantic cod

Distribution and Habitat

Grey seals are distributed in the temperate waters of the North Atlantic. They usually move in specific corridor areas to travel between their foraging areas offshore and their haul-out sites on land (Jones et al. 2015). Satellite telemetry data from Canada show that West Atlantic grey seals perform much longer foraging trips (averaging 5-12 days) and often travel much larger distances than East Atlantic grey seals (Breed et al. 2009).

Grey seal populations in the North Atlantic. Iceland has been noted to be genetically different than the other Northeast Atlantic grey seals (Frie 2009).

North Atlantic Stocks

Found only in the North Atlantic, 3 populations of grey seals are recognized: the Northeast Atlantic, the Northwest Atlantic and Baltic Sea.

Northeast Atlantic

The Northeast Atlantic population is centred around the British Isles, ranging from Iceland, eastward along the coast of France, and north to Norway and the Kola Peninsula, Russia (Haug et al. 1994). Frie (2009) also noted that genetics studies indicate that the Icelandic grey seals are an isolated population.

The grey seal colony in the Faroe Islands seem to have evolved from UK colonies sometimes after the postglacial period due to geographical isolation. The Faroe Islands appears to have a localized population based on geographic isolation and genetics that is significantly different from Norwegian grey seals (Klimova et al. 2014). Movements of UK grey seals to the Faroe Islands have been documented (Mcconnell et al. 1999, Matthiopoulos et al. 2004), but the intensity or influence of such a migration is not known.

Norwegian populations are, on the other hand, connected to the UK and Russian populations (Henriksen et al. 2007).

Baltic Sea

The Baltic Sea population is concentrated in the central Baltic area, bounded by Sweden, Finland and Estonia (Harding et al. 2007)

The Baltic grey seal (Halichoerus grypus macrorynchus) is a recognised subspecies of the Atlantic grey seal (H.g.grypus). motivated by geographical separation and difference in birth timing (Oct.-Jan. in East Atlantic, Jan. – March in the Baltic, NAMMCO 2016a).

Northwest Atlantic

The Northwest Atlantic population is found from the north eastern United States to Cape Chidley at the northern tip of Labrador (60° N), with the largest concentration around Sable Island, off the Nova Scotia coast. Canadian grey seals form a single genetic population that is divided into three groups for management purposes based on the location of breeding sites. Most pups (81%) are born on Sable Island (Sable), while 15% are born in the Gulf of St Lawrence (Gulf) and 4% are born along the coast of Nova Scotia (CNS) (NAMMCO 2016a)

Grey seal populations in the North Atlantic. Iceland has been noted to be genetically different than the other Northeast Atlantic grey seals (Frie 2009).

Northeast Atlantic

A population modelling study indicated an increase in abundance of the total Norwegian grey seal population during the last 30 years, suggesting a total of 8,740 (95% CI = 7,320-10,170) animals estimated in 2011 (Øigård et al. 2012, NAMMCO 2016d). New boat based surveys carried out in 2014-2015 showed a significant decrease in the grey seal pup production compared with the counts in the period 2007-2008, likely due to high levels of by-catch in the monkfish fishery.

Bayesian state-space modelling methodology  was used for British grey seal populations. Estimated adult population size in 2014 was 95,200 (95% CI 76,400-127,500) (Øigård et al. 2012)

The most recent abundance estimate of grey seals in Iceland is of 4,200 (95% CI: 3,400-5,000) animals in 2012. The present population size of the Faroe Islands is probably on the level of 1,000-2,000 animals (NAMMCO 2016d). On the other hand, no updated population estimate is present since the early 1990s (Haug et al. 1994) from Russia, when the total grey seal population were calculated to be about 3,400. Following a remarkable increase in 2014, the total number of grey seals in the Wadden Sea (Danish, German and Dutch coasts) was 4,521 during the moulting period in spring. In France, the most recent data available was a count of 150 grey seals in 2007 (NAMMCO 2016d).

Northwest Atlantic

The most recent assessment of Canadian grey seals was completed in 2014. The model estimated a total grey seal pup production in Atlantic Canada of 93,000 (95% CI = 48,000 – 137,000), with an associated total population of 505,000 (95% CI = 329,000 – 682,000). The model predicts that population size in all three management areas continues to grow (NAMMCO 2016d).

In the United States, a survey was conducted in 2016 to estimate pup production in and efforts are underway to derive a minimum population estimate and population trend. A survey in 2002 counted a total of around 3,300 seals (Wood et al. 2007).

Baltic Sea

The last population survey in 2014 indicated around 33,000 seals in the Baltic and an increasing trend (NAMMCO 2016d).

Summary of abundance and trends of grey seals in the North Atlantic (NAMMCO 2016d)

© Amy Bishop

Northeast Atlantic

Iceland and the Faroe Islands

The Icelandic grey seal population increased from the 1960s until 1982, then likely decreased by about 3% (95% CI 1% – 5%) annually from 1982 to 2002. After 1990 the rate of population decline was probably more rapid at about of 6% per year, causing a marked decline since the mid-1990s (Hauksson 2007).

For the Faroe Islands, the present biological knowledge on grey seals is very limited, largely due to their inaccessible nature. This means that there has not, as yet, been a population assessment performed on grey seals in the Faroe Islands. Irregular observations around the islands indicate that the Faroese population has not shown a rapid increase, as has been evident for colonies around Britain and in West Atlantic (Bowen et al. 2003). These seals have most likely been hunted since the early human settlements on the islands in the 8th century. This has probably prevented the population from increasing above a certain threshold. In addition, since the establishment of aquaculture in the islands in late 1970s, seals have been subject to removals around salmon sea farms, and generally suffer high pup mortality, due to the breeding grounds being exposed to intense fall storms (Mikkelsen 2007). For the relatively small population of grey seals in the Faroes, removal of a significant number of animals around fish farms, together with high pup mortality, will have the potential for a significant impact on the size and development of the population (NAMMCO 2016d).

UK, North Sea and mainland Europe

In the UK, between the early 1960s and the early 1990s, grey seal pup production progressively increased. At colonies in the Inner and Outer Hebrides, production appeared to stabilize during the 1990s and has remained so. Pup production at colonies in Orkney and in the North Sea has continued to increase but in recent years the rate of increase has declined. This may imply that the UK grey seal population is encountering some density dependent factors, limiting its size (Duck and Thompson 2007).

In mainland Europe the grey seal was a common species during the Stone Age (8,000-5,500 BC). Along the North Sea coast populations started to decline substantially during the 11th century as a result of excessive hunting. The last breeding populations disappeared in the 16th century in the Wadden Sea, and before 1900 in the Kattegat-Skagerrak and the Southwestern Baltic as a result of an extermination campaign. No regular pupping occurred along mainland Europe until the end of the 1970s. Tracking of movements indicate these seal groups to be linked to the larger populations in the UK (Härkönen et al. 2007). It seems that the grey seal population is currently increasing in this area and establishing itself further in the Wadden Sea area and northwards (NAMMCO 2016a)

Northwest Atlantic

The part of the population in the Gulf of St. Lawrence increased from 15,500 (95% CI = 14,600-16,300) animals in 1970 to 62,700 (95% CI = 49,800-67,800) animals by 1996 and then declined to 22,300 (95% CI = 17,200-28,300) animals in 2000. On Sable Island the population increased from 4,800 (95% CI = 4,700-4,900) animals in 1970 to 212,500 (95% CI = 159,600-276,200) in 2000. Overall there has been a deterioration in ice conditions since 1996, which is supposed to have a negative impact on breeding success of the pagophilic species, including grey seals. On the other hand, the populations on Sable Island has experienced a different trajectory, with a continuous growth. This difference can be due to the higher mortality rates in the Gulf, and partially to a net movement of animals from one area to the other (Hammill et al. 2007).

The most recent assessment of Canadian grey seals was completed in 2014. A population model incorporating estimates of reproductive rates up to 2012 was fitted to pup production estimates up to 2010 to describe the dynamics of the grey seal population in Atlantic Canada. Combining all three herds, the model estimated a total 2014 grey seal pup production in Atlantic Canada of 93,000 (95% CI= 48,000 – 137,000) animals, with an associated total population of 505,000 (95% CI=329,000-682,000). The model predicts that population size in all three management areas continues to grow (NAMMCO 2016d).

The establishment of the grey seal population in US water is recent and little information is available to describe its status and trends. Efforts are, however, underway to derive a minimum population estimate and trend for the portion of the grey seal stock in U.S. waters, based on aerial surveys conducted in Massachusetts from 2005-2015 during grey seal moulting periods. In addition, the use of fixed-wing and rotary drones, as well as manned aircraft, was used to conduct surveys in 2016 over the grey seal breeding grounds in the U.S. These data will be used in coordination with those collected by Department of Fisheries & Oceans Canada (DFO) in 2016 to estimate pup production over the entire range of the stock (NAMMCO 2016d).

Baltic Sea

The grey seal population in the Baltic Sea went through a depression in the 1970s with numbers as low as only 3,000 individuals. The population is recovering after a century of bounty hunting and 3 decades of low fertility rates caused by environmental pollution. The grey seal population is monitored by counting the hauled out proportion of the animals during the annual moult. The counts are based on aerial photography and monitoring effort is synchronised between countries to reduce double counting. Population increase is calculated from the counts and has reached 10-12% per annum during the early 2000s, but has slowed to about 6% in recent years (NAMMCO 2016d). Counted numbers fluctuate annually because of weather and other factors, but clear increasing trends in populations can be observed in all parts of the Baltic Sea. The growing population has led to increased interactions with the fishery, and demands are being raised for the re-introduction of the hunt. Due to a potential risk of quasi-extinction, the overall recommendation is that hunting should be kept to a minimum, carefully documented and accompanied by close population monitoring (Harding et al. 2007).

© Pixabay
© Pixabay


Management plans for coastal seals in Norway were adopted and implemented by the Ministry of Fisheries and Coastal Affairs on 5th November 2010. The goal of the management plans is to ensure viable populations of harbour and grey seals within their natural distribution areas. Grey seals are monitored by counting pups and the government decided that the population should be stabilized so that 1,200 pups could be recorded annually. The quotas are based on scientific advice in accordance with the management plan. Three geographical Management Units (MU) for grey seals are used, based on biological evidence (the Southern MU from Lista to Stad; the Central MU from Stad to Lofoten; and the Northern MU from Vesterålen to Varanger). However, the administration of hunting licenses and hunting statistics is undertaken by the county authorities (NAMMCO 2016a).


In 2006, the Icelandic government published a management plan where a target grey seal population size of 4,100 was recommended (NAMMCO 2006). Management actions should be initiated if the population dropped appreciably below that number, but no specific population regulating method was mentioned.

United Kingdom

Under the Conservation of Seals Act 1970, the UK Natural Environment Research Council (NERC) has a duty to provide scientific advice to the government on matters related to the management of seal populations. NERC has appointed a Special Committee on Seals (SCOS) to formulate this advice. Formal advice is given annually based on the latest scientific information provided to SCOS by the Sea Mammal Research Unit (SCOS 2004).


Given the continuous distribution of the species and free movement of individuals in the Baltic Sea the species is treated as a single management unit, and the grey seal management principles are defined by the HELCOM 2006 Seal Recommendation. The long term objectives are: to allow population growth towards the carrying capacity, to allow the breeding seals to expand to suitable distribution in all areas of the sea, and attaining health status that secures continued existence of the populations. The population target limit is defined by the ecological carrying capacity (NAMMCO 2016a).


The Canadian grey seal population is managed by the governmental organization Fisheries and Ocean Canada. Currently the Canadian grey seal is considered a data-rich species, with three or more abundance estimates over a 15-year period, with the most recent estimate obtained within the last five years. Information (≤5 years old) on fecundity and/or mortality is also required in order to determine sustainable levels of exploitation.

All Canadian Atlantic seal populations are managed under a precautionary approach. Three types of reference points are identified: the Critical Limit, which is the level below which a population is considered to have likely experienced serious and irreversible harm, and below which, all human induced removal should be stopped; the Precautionary Reference Point, above which the population is considered to be healthy and conservation is not considered to be of greatest concern; the Target Reference Point, the level at which industry and management would like the population to remain.

The Canadian Standing Senate Committee on Fisheries and Oceans has in 2012 recommended to the Department of Fisheries and Oceans to implement for a period of four years, starting in 2013, a targeted removal program in the southern Gulf of St. Lawrence to hopefully reduce the level of the grey seal impact on groundfish.

Northeast Atlantic

Norwegian grey seals are subject to a non-commercial hunt. Hunting is usually performed by shooting the animal from land and retrieving it in the water with the support of a small boat.

Seal hunting in Iceland is focussed almost entirely on seal pups, mainly for the skin; but the meat, the blubber (fat) and the flippers played an important role for human consumption in the past. Pups are taken when they are a few weeks old, just towards the end of lactation. Annual takes are less than 400 pups. The grey seal pups are almost entirely caught in the whelping areas, using either a seal club or a rifle from a very short distance. For hunting of adult grey seals a rifle is used. The grey seal pups’ skins are tanned for the leather industry, and this is a very strong leather material. The meat is used fresh, salted or smoked.

Traditional seal hunting virtually ceased in the Faroe Islands since the late 60s with the new weapon regulations, banning the use of rifle as hunting weapons. In the early 1980s, fish farms were introduced and with them the problems of seals’ interaction with the farmed fish. Farmers with licence were then given permission to possess rifles and they have to report to the Ministry, in case of a shot animal. There is no longer any tradition to utilise seal meat and blubber or the fur in the Faroe Islands (NAMMCO 2016c).


The Baltic grey seal population is now recovering after commercial over-harvesting in the first half of the 20th century. Seal hunting was stopped entirely in Sweden in 1975 and in Finland in 1982, and was restarted in 2001 and 1997, respectively. Seal hunting is now strictly regulated in both countries. Hunting from boats is not permitted. During the spring period seals are hunted on the ice. Seals sink quickly in the Baltic because the salinity of the water is very low. Also the water is not very clear, which makes retrieval of sunken seals difficult. Therefore, hunters prefer areas of shallow water where sunken seals can be retrieved more easily. Hunting is forbidden in seal reserves, which include all the major resting-places for seals in the Baltic (NAMMCO 2016c).

Northwest Atlantic

A commercial juvenile grey seal hunt usually runs from early February until early March, mainly along the Eastern Shore of Nova Scotia and in the Southern Gulf of St Lawrence. The grey seal Total Allowable Catch for 2016 was 60,000 animals. All Commercial Seal license holders are subject to complete a mandatory training.

Reported catches in NAMMCO member countries

CountryYearAreaCatch TotalQuota
Faroe Islands2019Faroes34
Faroe Islands2018Faroes50
Faroe Islands2017Faroes117
Faroe Islands2016Faroes111
Faroe Islands2015Faroes140
Faroe Islands2014Faroes102
Faroe Islands1992-2013FaroesN/A
Norway2019Norwegian coast58200
Norway2018Norwegian coast66200
Norway2017Norwegian coast81200
Norway2016Norwegian coast33210
Norway2015Norwegian coast82
Norway2014Norwegian coast216
Norway2013Norwegian coast194
Norway2012Norwegian coast64
Norway2011Norwegian coast111
Norway2010Norwegian coast363
Norway2009Norwegian coast516
Norway2008Norwegian coast458
Norway2007Norwegian coast456
Norway2006Norwegian coast272
Norway2005Norwegian coast379
Norway2004Norwegian coast302
Norway2003Norwegian coast353
Norway2002Norwegian coast110
Norway2001Norwegian coast105
Norway2000Norwegian coast176
Norway1999Norwegian coast130
Norway1998Norwegian coast34
Norway1997Norwegian coast36
Norway1996Norwegian coast31
Norway1995Norwegian coast31
Norway1994Norwegian coast31
Norway1993Norwegian coast31
Norway1992Norwegian coastN/A

This database of reported catches is searchable, meaning you can filter the information by for instance country, species or area. It is also possible to sort it by the different columns, in ascending or descending order, by clicking the column you want to sort by and the associated arrows for the order. By default, 30 entries are shown, but this can be changed in the drop-down menu, where you can decide to show up to 100 entries per page.

Carry-over from previous years are included in the quota numbers, where applicable.

You can find the full catch database with all species here.

You can find a complete file with all comments and explanations here, under Overview Documents.

For any questions regarding the catch database, please contact the Secretariat at

Other human impacts

The most important anthropogenic sources of mortality for grey seals, other than hunt, are by-catches during fishing operations, removal during interactions with fish farms and pollution.


In Norway, the levels of by-catch of grey seals in fishing operations are estimated using three different sources: mark recapture data, data from the Coastal Reference Fleet (a monitored segment of the coastal fishing fleet), and from modelling population trajectories. For grey seals this resulted in an estimate of total by-catch of 8,379 animals for the period 1997-2014, with an annual by-catch of 466 grey seals. The by-catch of grey seals is about twice the annual hunt (240 seals). It is likely that the level of by-catches has been increasing in recent years north of 62°N due to an increase in fishing effort with large mesh gill nets, particularly in the monkfish fishery.

In Iceland, the most reliable by-catch data originate from the March-April cod gillnet research survey and with fisheries observers (1% coverage of the fleet and representative geographical spreading). The main fisheries of most concern are assumed to only be the gillnet fishery for cod and lumpsucker, with species of concern being, respectively, harbour porpoise and harbour and grey seals.

In the Faroe Islands, the use of pelagic or semi-pelagic trawl fishery with very high vertical opening and herring set gillnet is source of mortality for several marine mammals, including grey seals (NAMMCO 2016a).

There is an increasing problem with interactions between seals and commercial fisheries in the Baltic, and herring gillnet fishery is particularly vulnerable to this (NAMMCO 2016c).

In Canadian waters in the Northwest Atlantic, on the other hand, no data are available on incidental catches in fishing operations, but the numbers are thought to be small (NAMMCO 2016a)

Fish farming

In the Faroe Islands, the most significant human-grey seals interaction is in connection with salmon farming. The total numbers of grey seals removed at aquaculture farms in the Faroe Islands are estimated to be around 150-250 grey seals annually. These removal levels (150-250 seals) are around 10-20% of the rough estimate of population size (NAMMCO 2016a).


Pollutants have been problematic especially for the Baltic grey seal population during several decades. Bergman (1999) reported, in a long term study, earlier, reduced reproductive ability with lesions of the female reproductive organs and rate of pregnancy, as well as a disease complex in adult individuals of both sexes. This, together with hunting, was the major contributor of the population decrease in the 1970s.

In 2001, NAMMCO’s Scientific Committee noted that the abundance of grey seals around Iceland had declined sharply, while there were apparent increases in grey seal abundance in other areas. Grey seal abundances are often evaluated by determining the number of pups born in a season, usually using aerial surveys. This can either be used as an index of total population abundance or the latter can be estimated from pup production via numerical modelling. Ongoing research has been addressing the best way to obtain viable population estimates from pup counts, for example using a Bayesian model approach (Øigård et al. 2012).


A programme for estimating the abundance of grey seals in the Faroe Islands started in summer 2018, visiting all islands except Suðuroy and using both boats and drone footage (National Progress Report Faroe Islands 2018). During the summer of 2019, the total shoreline of the archipelago was surveyed by boat (with the exception of the east side of Suðuroy), and all seals hauled-out and in the water were counted. Each island was visited from one to three times and in high-density areas, footages captured from drone were used for the seal counts to improve accuracy (National Progress Report Faroe Islands 2019). In 2020, there are plans to expand the study to include camera traps and satellite tracking, in order to improve the accuracy of the estimate.


The latest aerial census to estimate the current status of the Icelandic grey seal population was conducted in 2017, with the analyses published in 2019 (Granquist and Hauksson 2019). The total population size was estimated to be 6269 (95% CI: 5375 – 7181). Breiðafjörður was the most important pupping area in Iceland, with 58% of the total pup production in 2017.

In Iceland, five grey seal pups were tagged with satellite tags to map habitat use in October 2016 (National Progress Report Iceland 2018). The results of this research were published in 2019 (Baylis et al. 2019).

A study of Icelandic grey seal genetics was initiated in 2016, in cooperation between the MFRI, ISC, the Natural History Museum of Denmark and Main University. Analysis is ongoing (National Progress Report Iceland 2019).

A project investigating environmental toxicants in seals in Icelandic waters was initiated by MFRI in 2017 and analysis is ongoing (National Progress Report Iceland 2019). The focus of the project is to investigate the contents of new contaminants of concern in marine mammals, including new brominated flame retardants and PFAS (per- and polyfluoroalkyl substances). The project is an international cooperation between Sweden (Naturhistoriska Riksmuséet and Stockholm University), Greenland (Grönlands Naturinstitut) and MFRI (Iceland).

Efforts to estimate by-catch of grey seals in fisheries are also ongoing at the MFRI.


Research has been conducted by the Norwegian Institute of Marine Research and UiT the Arctic University of Norway to obtain knowledge of feeding habits and prey consumption of grey seals. During 1999–2010, prey were recovered from 182 grey seal gastrointestinal tracts and 199 faecal samples that had been collected in Finnmark, Nordland and Rogaland counties. The most important prey were revealed to be saithe Pollachius virens, cod Gadus morhua and wolffish Anarchichus spp. Wolffish was mainly eaten by seals ≥ five years old. Otherwise, the data did not suggest important temporal or spatial variations between the main prey items in the grey seal diet. However, capelin Mallotus villosus was eaten during spring in Finnmark suggesting that seasonally abundant pelagic fish species could be regionally important (National Progress Report Norway 2019).

Total annual grey seal consumption of various species has also been estimated using bio-energetic modelling. The input variables were seal numbers, energy demands, diet composition in terms of biomass and energy densities of prey species. Assuming the observed grey seals diet composition in the sampling areas were representative for the diet along the Norwegian coast, the mean total annual consumption by 3850 grey seals was estimated to be 8084 tons in Norwegian waters; saithe (3059 tons), cod (2598 tons) and wolffish (1364 tons) (National Progress Report Norway 2019).

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