Working Group on the Integrated Ecosystem Assessment of Icelandic Waters (WGICE; outputs from 2025 meeting)

This report provides the scientific basis and the ecoregion assessment details used on the 2026 update of the Icelandic Waters Ecosystem Overview. ICES Ecosystem Overviews use a risk-based approach to identify the main human activities and pressures affecting an ecoregion, describe key environmental drivers and temporal trends, and link these pressures to their impacts on ecosystem components. In preparation for this update, the Working Group on the Integrated ecosystem assessment of Icelandic Waters (WGICE) conducted a risk assessment to identify the current main anthropogenic pressures in the ecoregion and describe how these impact the ecosystem components. The work on risk assessment followed the ICES Ecosystem Overviews Technical Guidelines (ICES 2023) to complete the risk assessment. Twelve sectors, nine pressures and six ecosystem components were assessed for the Icelandic Waters ecoregion. The high-risk pressures include selective extraction of species, collateral mortality, marine litter, physical seabed disturbance, and noise. The human activities contributing most to these pressures include Fishing, Wastewater and Shipping, with Fishing contributing by far the largest.Commercial fisheries occur on a large-scale in the ecoregion and target more than 40 demersal, pelagic and benthic stocks, contributing to all the high-risk pressures, through selective extraction of species, collateral mortality via bycatch of non-target species, physical seabed disturbance from widespread use of bottom-contacting gear, generation of marine litter mainly through ghost gear, and generation of low levels of noise. Wastewater is another land-based source of marine litter, releasing microplastics and macro debris from treated and untreated waste into coastal waters. Increased shipping traffic over the past decade also raises concerns about marine litter and vessel traffic noise.Benthic habitat and biota, and fish, are the ecosystem components most at risk, followed by seabirds, marine mammals and pelagic habitat. Benthic habitat and biota are most at risk from physical seabed disturbance, collateral mortality and selective extraction. Fish are mostly affected by selective extraction and collateral mortality. Marine litter, especially micro-plastics, can disperse widely and affect all ecosystem components. The current state, and where possible, temporal trends of each ecosystem component are also described.Apart from anthropogenic pressures, climate change is also of concern in the ecoregion. Long-term observational hydrographic data shows that warming is evident throughout the Iceland shelf in the near-surface and near bottom layers. This has driven a shift in capelin distribution, a key forage fish in the ecoregion, and is favouring more boreal opportunistic groundfish, while colder Arctic species have declined. Several key benthic and pelagic populations, including northern shrimp, Iceland scallop, and puffins have experienced significant declines linked to a combination of warming, altered prey availability, and additional pressures such as fishing mortality, predation, and disease. These climate-driven changes in the distribution and abundance of commercial fish stocks carry cascading effects on fishing effort, foodweb structure, and ecosystem function, with socio-economic and cultural implications for a region highly dependent on fisheries.This report provides an evidence base for prioritizing management action to protect the ecoregion from anthropogenic pressures and to mitigate the effects of climate change.