Brünnich’s guillemot (Uria lomvia)
Since the Brünnich’s guillemot feeds on key species in the ecosystem and is so abundant, it may be a good indicator for the productivity of the ecosystem. The Brünnich’s guillemot makes up the largest proportion of the seabird biomass in the Barents Sea (over 60%) and was Red Listed in 2010 due to the decline in its population. It is a generalist and an important predator on capelin, polar cod, pelagic amphipods and krill.
What is being monitored?
Cite these dataNorwegian Polar Institute (2019). Brünnich's guillemot breeding populations, percentage of colony average. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL: http://www.mosj.no/en/fauna/marine/brunnichs-guillemot.html
|Diabas||%||Norwegian Polar Institute||111||101||147||122||116||105||128||132||101||119||93||86||85||97||85||87||69||75||68||71|
|Alkhornet||%||Norwegian Polar Institute||88||143||119||143||118||93||123||139||128||150||135||93||127||72||56||61||57||53||69||64||67|
|Sofiekammen||%||Norwegian Polar Institute||115||84||91||137||107||71||120||75|
|Grumant||%||Norwegian Polar Institute||130||111||109||127||183||142||179||112||71||67||62||63||59||62||65||60|
|Tschermakfjellet||%||Norwegian Polar Institute||166||120||141||117||89||147||110||146||142||83||108||69||80||54||62||38||51||58|
|Fuglehuken||%||Norwegian Polar Institute||152||131||124||145||145||145||170||124||141||127||110||111||107||99||96||66||68||64||62||55||56||48||54||53||47|
|Ossian Sarsfjellet||%||Norwegian Polar Institute||119||105||123||121||112||89||148||174||118||147||131||120||135||99||85||105||92||92||87||80||72||75||82||81||63||61||71||59||55|
|Bjørnøya, southern part||%||Norwegian Polar Institute||89||100||104||128||119||123||112||125||112||109||108||106||101||87||110||91||88||85||90||92||93||87||84||88||60|
|Bjørnøya, Evjebukta||%||Norwegian Polar Institute||125||112||111||112||106||101||99||99||100||89||94||90||86|
|Jan Mayen||%||Norwegian Polar Institute||134||149||108||90||83||75||61|
3 counts of each plot (1 count per observer) are made 4–8 times per season, from late incubating to early rearing periods. Counts are made with 10×40 binoculars.
On Spitsbergen, counts are only made in the western part. Results do not necessarily apply to colonies in eastern Spitsbergen; additional research would be needed.
The method is internationally standardized (Walsh et al. 1995), and is also standardized with the SEAPOP Norwegian monitoring.
All data are stored in the Norwegian Polar Institute’s seabird database, and in SEAPOP's databases.
Reference level and action level
Red List status: a 15–30% reduction in the population over 10 years means that the species qualifies for the category "Near Threatened".
Barents Sea Management Plan (monitoring group): a reduction in the population of 20% or more during more than 5 years, or unsuccessful breeding 5 years in a row.
Status and trend
In all, 142 colonies are known in Svalbard, with a total breeding population estimation of 615,000 pairs. The largest colonies (> 100,000 pairs) are situated in the southeastern part of Spitsbergen (Koval'skifjella and Stellingfjellet) and on Hopen and Bjørnøya. More than 80 % of the Svalbard population breeds within this "triangle".
Following a period of relative stability or increase, the breeding population of Brünnich’s guillemots has been declining by ca 4% per year since the mid-nineties. This decline has been observed in all the monitored colonies on Spitsbergen and Bjørnøya. An equivaltrend has been observed in Finnmark colonies (mainland Norway). Trends for colonies in East-Svalbard are currently unknown.
The cause of the Brünnich’s guillemot decline in Svalbard is likely connected to the warming of oceans in the species’ winter habitats near Iceland and Greenland. Here the warming most likely has led to changes in the food web and different access to prey for the Brünnich’s guillemot.
Brünnich’s guillemots are hunted in Greenland, but the hunting pressure has been decreasing since 2001. Harvesting is therefore probably not causing the recent Brünnich’s guillemot decline in Svalbard. By-catching of guillemots in fishing gear and/or oil pollution may also contribute to the decline in the population.
All colonies of Brünnich’s guillemots monitored in Svalbard (western Spitsbergen and Bjørnøya) show signs of decline since the mid-1990s.
The number of breeding birds has declined by approximately 5% per year. This means that the average size of the Brünnich’s guillemot population has probably declined by a third in the last decade, at least on Bjørnøya and western Spitsbergen.
Brünnich’s guillemots play an important role in the ecology of Svalbard through their transport of large amounts of nutrients from the marine environment to the terrestrial environment, when they fertilize local areas of tundra with their guano (excrement). A reduction in the breeding population may thus reduce this nutrition "pump", which may have consequences for the terrestrial environment.
About the monitoring
The Brünnich’s guillemot is one of the most numerous seabirds in Svalbard, and breeds in dense colonies all over the archipelago. The diet of adult Brünnich’s guillemots is more varied than that of common guillemots. It consists mainly of fish and crustaceans, but during the breeding season, chicks are essentially fed with fish, such as polar cod (the most important prey item in Spitsbergen) or capelin (the most important prey item on Bjørnøya).
Brünnich’s guillemots are thus considered to be a good indicator of the availability of pelagic fish stocks. They are also very sensitive to oil spills and by-catching in fishing nets.
Brünnich’s guillemots have shown a drastic decline in population size all over Svalbard since the mid-1990s. The species is now red-listed in Norway (Near Threatened status).
Brünnich’s guillemots are monitored on Bjørnøya and western Spitsbergen. The size of several colonies is estimated annually in order to detect short- and long-term changes in population size. Moreover, to explain and even predict those changes, several other parameters are monitored annually. This includes the annual adult survival of Brünnich’s guillemots and the diet of their chicks during the rearing period. On Bjørnøya, the average breeding success of Brünnich’s guillemot is also estimated annually.
In each monitored colony, the total number of Brünnich’s guillemots present in some study plots is counted annually. This represents the best and internationnaly accepted method to detect changes in a guillemot colony, and thus the population size.
Places and areas
Fuglehuken is one of the largest Brünnich’s guillemot colony on western Spitsbergen. Ossian Sarsfjellet is located innermost in Kongsfjorden and is easily accessible from Ny-Ålesund. Bjørnøya has one of the largest Brünnich’s guillemot colonies in Svalbard, and the southernmost.
Relations to other monitoring
- Monitoring programme
- International environmental agreements
- Voluntary international cooperation
- Related monitoring