Atlas of Seabirds of Portugal

Distribution, movements and phenology

The Northern Gannet breeds in the North Atlantic between March and August, mainly in north-west Europe and Canada. Between September and November, the European population migrates to the coasts of West Africa and the European Atlantic, with a portion entering the Mediterranean (Billerman et al. 2026). They use the Portuguese Mainland coast as a migratory corridor, occurring along the entire continental shelf (Meirinho et al. 2014; Bernard et al. 2026). Furthermore, the Mainland is also an important wintering area for birds from some colonies (Grecian et al. 2019; Garthe et al. 2024). A large number of immature birds remain in these waters throughout the year (Catry et al. 2010a). In the Azores and Madeira, it occurs in small numbers, mainly during migration (Meirinho et al. 2014).
Data obtained from 15 birds fitted with GPS tags in 2018 and 2019, originating from the United Kingdom, confirm the known distribution of the species in the Mainland region. Of note is the higher concentration between Caminha and Ericeira, with some use of deeper waters. Based on these data, no occurrences were recorded in the sub-areas of the Azores or Madeira.

Abundance and population trends

The global population has been estimated at between 1.5 and 1.8 million mature individuals, showing an upward trend, of which 1.37 million breed in Europe (BirdLife International 2025). In Mainland Portugal, the Northern Gannet is one of the most abundant seabirds, particularly between September and March. Between 2010 and 2015, the population was estimated at between 79,518 and 101,700, representing up to 10% of the global population (Araújo et al. 2022b). Furthermore, during the post-breeding migration in 2015, more than 200,000 birds were counted passing southwards from Cape Carvoeiro (Elmberg et al. 2020). The highest densities of the species are recorded in the central and northern parts of the Mainland, with a moderate upward trend observed in the migratory flow during the pre-breeding season (Fagundes et al. 2024).
However, this population has not achieved Good Environmental Status for the abundance indicator. There is no information regarding abundance or population trends for the Azores and Madeira, making it impossible to assess the environmental status.

Ecology and habitat

It is a marine species found in areas of the continental shelf and slope, and may be observed either alone or in large groups (Catry et al. 2010a). It feeds on schools of pelagic fish, such as mackerel, horse mackerel, sardines and needlefish, taking advantage of discards from commercial fishing (Billerman et al. 2026).

Threats and conservation

The Northern Gannet is one of the species most frequently captured as bycatch in fishing gear in Portugal, with a particular incidence in demersal longline fishing (Oliveira et al 2015; Calado et al. 2021). The implementation of fishing methods that minimise this risk of mortality should be a priority for the conservation of the species (BirdLife International 2025). It is also particularly vulnerable to collisions with wind turbines in offshore wind farms (Bradbury et al. 2014), which raises further concerns at a time of rapid expansion in this sector. The impacts of marine pollution, particularly from plastics, have not yet been fully quantified, but are believed to compromise breeding success. Furthermore, outbreaks of diseases such as avian influenza have caused localised population declines and represent an emerging threat (Lane et al. 2024).