ICES Report Warns Brown Crab in Decline Across Northern Europe

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ICES report warns of steep declines in brown crab fisheries across Northern Europe, citing overfishing, poor data, and weak management systems

The International Council for the Exploration of the Sea (ICES) has warned that brown crab (Cancer pagurus) stocks across Northern Europe are in steady decline, with landings from Ireland and the UK falling sharply and early signs of overexploitation appearing in several management areas.

According to the ICES Cooperative Research Report 360 (CRR360), landings of brown crab have dropped consistently since 2016. The report, An Overview of the Brown Crab (Cancer pagurus) Fisheries and Stock Trends in the Northeast Atlantic , authored by a multinational team of scientists, reveals that most of the major fisheries around Ireland and the British Isles are showing either declining catch rates or reduced average sizes, both indicators of excessive fishing pressure.

ICES notes that while brown crab remains one of the most commercially valuable crustacean species in European waters, the fishery is managed with minimal regulation and suffers from critical data gaps that hinder effective conservation.

Declining Stocks Around Ireland and the British Isles

In Ireland, where brown crab is one of the country’s most valuable shellfish exports, catch per unit effort (CPUE) has fallen markedly in all key fishing zones, including the Malin Shelf, southwest coast and Celtic Sea. The report identifies a concerning pattern of declining recruitment, with fewer mature crabs entering the fishery each year.

Irish landings, which peaked in 2016, have fallen by more than 30%, and ICES concludes that current exploitation rates are not sustainable. The lack of stock assessments and limited biological data have prevented a full evaluation of stock status, but scientists warn that a continuation of the current trend will lead to long-term depletion.

Scotland, which accounts for the largest share of brown crab landings in Europe, has seen a similar downturn. Landings have fallen by more than half in less than a decade, with notable reductions in both catch rates and mean carapace size across most management units. The CRR360 attributes these declines to heavy exploitation in traditional grounds around Shetland, Orkney and the east coast, combined with a near-total absence of catch limits or seasonal closures.

In England and Wales, the fishery remains important for small-scale coastal vessels, but several regions—particularly the eastern English Channel and the North Sea coast—show evidence of reduced stock density and smaller average sizes. The report highlights that while these fisheries contribute to local economies, the continued lack of coordinated management between devolved administrations undermines effective conservation.

Northern Ireland’s smaller fleet has also reported a drop in CPUE, and while landings data remain patchy, ICES categorises the stock as uncertain but likely declining.

Scandinavian and French Fisheries Show Mixed Trends

The CRR360 notes that in Scandinavia and parts of the southern North Sea, catch rates remain stable or are slightly increasing. In Norway, where the crab fishery has expanded northwards in recent years, scientists report healthy catch levels but limited monitoring. Sweden and Denmark have recorded consistent landings, but both lack standardised sampling programmes.

France, which operates significant brown crab fisheries in the English Channel and Brittany, shows mixed results. Catch rates in the western Channel remain strong, but landings in the eastern Channel have declined, and the stock status is unknown. French management relies primarily on minimum landing sizes and regional licensing, but ICES considers these measures insufficient to ensure sustainability.

Weak Management and Poor Data

Across Europe, brown crab fisheries are managed primarily through minimum conservation reference sizes (MCRS), which prevent the harvest of immature crabs but do nothing to regulate overall fishing pressure. ICES scientists stress that without catch limits, effort controls or stock-based management plans, the species is increasingly vulnerable to overfishing driven by high market demand and price.

The report also highlights major scientific gaps, including uncertainties around growth rates, age structure, and migration patterns. These deficiencies, combined with the absence of long-term biological monitoring, make it impossible to estimate fishing mortality accurately or determine safe harvest levels.

“Despite its high commercial value, brown crab remains one of the least understood and least regulated crustacean fisheries in Europe,” the authors note. “In most cases, management is reactive rather than precautionary.”

Economic and Ecological Consequences

The decline in brown crab availability has already begun to affect processing plants and export markets, particularly in Ireland and Scotland, where much of the catch is sold to continental Europe and Asia. Reduced landings mean lower profitability for inshore fleets, many of which depend almost entirely on shellfish due to the loss of whitefish quota opportunities.

ICES warns that without improved management, both the economic viability of the fleet and the ecological stability of coastal crab populations are at risk. The organisation recommends the creation of stock-specific management objectives, better data collection on effort and landings, and the development of long-term monitoring programmes across all participating nations.

Call for Coordinated Reform

The report concludes that “improved management in brown crab fisheries is urgently needed to incorporate objectives for both sustainable and viable fishing and to balance the productive capacity of stocks with the socio-economic realities of the fleets involved.”

While some newer fisheries, such as those in Scandinavia and the southern North Sea, appear stable for now, ICES cautions that these regions could face the same collapse trajectory as Ireland and Scotland if exploitation remains unchecked.

The message from CRR360 is clear: Europe’s brown crab stocks are at a crossroads. Without coordinated national action, stricter monitoring, and an end to open-access exploitation, one of the region’s most valuable shellfish species could face irreversible decline.

The report is authored by Carlos Mesquita, Oliver Tully, Guillermo Martin, Johanna Bjånes Marcussen, Fabian Zimmermann, Johanna-Luise Kozák, Holger Haslob, Chun Chen, Matthew T. Coleman, Samantha R. Blampied, Rosslyn McIntyre, Natalie Hold, Carrie McMinn, Lies Vansteenbrugge, Tiago Veiga-Malta, Ailsa Ellis, and Martial Laurans

Read: An overview of the brown crab (Cancer pagurus) fisheries and stock trends in the Northeast Atlantic

Source: ICES