Recent near misses in the Norwegian waters and seabirds

Seabirds are among the most threatened group of bird species, with pollution, especially oil, being a key threat. Following an oil spill, seabirds frequently come in to contact with oil floating on the sea’s surface, which can affect them in many direct and indirect ways. Due to their ecology, some seabird species are more sensitive to oil than others. We can therefore estimate the vulnerability of different species to oil by taking into account their behaviour and life history characteristics. For example, species that spend a large amount of time on the sea surface, such as auks (e.g. Razorbills, Puffins) and sea-ducks (e.g. eiders), are more sensitive to oil spills than more aerial species and those that stay closer to the coast (e.g. gulls, terns). By taking into account the ecology of different species we can calculate an Oil Vulnerability Index (OVI), with OVI scores ranging from low values, indicating no or very little vulnerability to oil, to maximum scores, indicating high vulnerability. Once we have OVI scores for each species, we can combine them with breeding and non-breeding spatial distribution information to identify locations where large concentrations of seabirds that are vulnerable to oil pollution may occur.

Map illustrating the recent incidents and the vulnerability of the seabirds to oil (downloadable version available below the text)

The eastern North Atlantic Ocean holds large concentrations of breeding and wintering seabirds. Since November there has been three incidents in the Norwegian waters involving vessels that could have resulted in major oil spills: a frigate that collided with a Malta-registered oil tanker off Bergen in November 2018; a shrimp trawler that ran aground in north Svalbard in December 2018; and the Viking Sky cruise ship that lost power off Hustadvika in March 2019. If conditions were different, how would a major oil spill at these locations affect the wintering seabirds? We can explore this by looking at our spatial OVI map for this region for seabirds during non-breeding season. The map highlights the sensitivity of seabirds to oil spills during non-breeding season, from low to extremely high (note that this is based on seabird distributions only so it does not consider seabird densities). Looking at the incident in Svalbard, if an oil spill had occured it is unlikely to have had a major negative impact on wintering seabird populations, as we would expect, with few seabirds present in these waters at this time of year. Conversely, the incidents off Bergen and Hustadvika could have had a greater negative impact on non-breeding seabirds, due to the extremely low sensitivity of seabirds in this area. A large number of species winter off the coast of Norway and their behaviour (specifically spending a large amount of time on the water) means they are susceptible to oil spills. The species potentially affected by the oil spill would have included large numbers of Razorbill, Little Auk, Puffin, Guillemot, Common Scoter and Great Northern Diver. Fortunately, for these seabirds and other marine life, these  incidents did not result in any major spills.