Icelandic Waters Ecoregion – Ecosystem Overview

Human activities and their pressuresFishing poses the highest impact risk to ecosystem state components through selective extraction of species, physical seabed disturbance, incidental bycatch, and marine litter resulting from abandoned, lost, or discarded fishing gear (ALDFG).Fishing intensity has declined over the past two decades with the implementation of harvest control measures.Widely distributed pelagic stocks continue to experience fishing mortality above FMSY because of the absence of coastal state agreements. This poses a risk to long-term sustainability.Fishery closures have been established that are a step toward protecting the ecoregion’s diverse benthic habitats and vulnerable marine ecosystems (VME) from disturbance by bottom-contacting fishing gear.To a lesser extent, wastewater and shipping pose a risk to all ecosystem components by releasing marine litter, namely microplastics and other contaminants.The risks posed by wastewater are aggravated by limited wastewater treatment infrastructures. Pressures associated with shipping are anticipated to increase in the ecoregion.State of the ecosystemPrimary production is high in Icelandic waters, and phytoplankton biomass is increasing on the south Iceland shelf.Stocks of northern shrimp (Pandalus borealis), Norway lobster (Nephrops norvegicus), Atlantic halibut (Hippoglossus hippoglossus), and beaked redfish (Sebastes mentella) remain below historical biomass levels, while the biomasses of mackerel (Scomber scombrus) and Norwegian spring spawning herring (Clupea harengus) are below target.Populations of fulmars (Fulmarus glacialis) and kittiwakes (Rissa tridactyla) continue to decline in the ecoregion.The status of harbour seal (Phoca vitulina) remains a conservation concern in the ecoregion.Recent changes in capelin (Mallotus villosus) abundance and distribution are expected to have important consequences on Atlantic cod (Gadus morhua), seabirds, and whales in the ecoregion.Climate changeSurface and bottom waters of the Iceland shelf have warmed by > 1.1°C since 1975, primarily due to increased northward transport of Atlantic Water into the ecoregion.Warming is most pronounced in surface waters in the north, where a shift in zooplankton community composition from Arctic to boreal large copepod taxa is evident.Rising temperatures have contributed to the decline of northern shrimp and Iceland scallop (Chlamys islandica) populations, to the shifting capelin distribution beyond the Iceland shelf, and to groundfish species moving northward or to deeper waters.Surface water pH is declining on the shelf. Acidification effects on marine biota and habitats are largely unknown and are a key concern in the ecoregion.Warming is projected to continue and result in the spatial redistribution of commercially harvested species on the Iceland shelf.Environmental and socio-economic contextFisheries significantly contribute to national revenues and employment and have high cultural importance in the ecoregion.Balancing economic and social benefits from fisheries with ecosystem conservation objectives is a key trade-off in the ecoregion.The rapid growth of tourism, shipping, and finfish aquaculture is raising additional societal concerns and trade-offs among marine sectors and associated pressures.