Invasive species
The Icelandic Waters ecoregion has 22 non-indigenous and cryptogenic (obscure or of unknown origin) species. This is a diverse group of species belonging to phytoplankton, macroalgae, crustaceans, bivalves, tunicates, and fish. Four of those species (the common seaweed Fucus serratus, Atlantic rock crab Cancer irroratus, brown shrimp Crangon crangon, and flounder Platichthys flesus) are considered invasive in Icelandic waters but are native to other ICES ecoregions. The majority (twelve) of the non-indigenous species arrived between 1950 and 1999, with six species arriving since the beginning of the 21st century. Consequently, the annual rate of discovery increased from 0.2 per year during 1950–1999 to 0.4 per year during 2000–2016. At least one of the recently arrived non-indigenous species, the Atlantic rock crab Cancer irroratus, is not yet registered in the neighboring areas (Faroe Plateau, Barents Sea, Greater North Sea, and Norwegian Sea).
The main pathway for introductions is vessels, either through ballast water or ship hull fouling. Secondary spread from neighbouring areas may account for the arrival of a few non-indigenous species. Ecological impacts caused by the non-indigenous species in this region is very poorly known.
Threatened and declining species and habitats
Table 1: Threatened and declining species in the Icelandic Waters ecoregion, according to OSPAR.
| SCIENTIFIC NAME | COMMON NAME |
| SEABIRDS | |
| Rissa tridactyla | Black-legged kittiwake |
| Uria lomvia | Thick-billed murre (or Brünnich's guillemot) |
| FISH | |
| Anguilla anguilla | European eel |
| Centrophorus squamosus | Leafscale gulper shark |
| Cetorhinus maximus | Basking shark |
| Dipturus batis | Common skate |
| Hoplosthethus atlanticus | Orange roughy |
| Lamna nasus | Porbeagle |
| Petromyzon marinus | Sea lamprey |
| Salmo salar | Salmon |
| Squalus acanthias | [Northeast Atlantic] spurdog |
| MARINE MAMMALS | |
| Balaenoptera musculus | Blue whale |
| Eubalaena glacialis | Northern right whale |
Table 2: Threatened and declining habitats in the Icelandic Waters ecoregion, according to OSPAR.
| HABITATS |
| Coral gardens |
| Deep-sea sponge aggregations |
| Intertidal mudflats |
| Lophelia pertusa reefs |
| Modiolus modiolus beds |
| Seamounts |
| Zostera beds |
