Spider Crab Welfare: Aggregations, Moulting, and Trawl Capture

European spider crabs form massive aggregations during their annual moulting period, making them vulnerable to trawling. Their welfare during capture and the moulting process deserves attention.

Key Facts

European spider crabs aggregate in the thousands during the spring moulting season in shallow coastal waters
During moulting, crabs are soft-shelled and extremely vulnerable to predation and physical damage
Trawling through aggregations during moulting is particularly damaging because crabs cannot flee and are easily injured
Spider crabs are increasingly valuable in the seafood market as traditional crab stocks decline
Their aggregation behaviour makes them highly vulnerable to targeted fishing during predictable annual events

Welfare Considerations

Moulting spider crabs in soft-shell condition are physiologically vulnerable and unable to defend themselves from physical damage. Trawling through moulting aggregations causes crushing injuries, limb loss, and death in the net before crabs even reach the deck. Soft-shell crabs that survive capture cannot withstand the same handling as hard-shell individuals. Seasonal closure of moulting aggregation areas would protect spider crab welfare at their most vulnerable and allow populations to reproduce successfully before being fished.

What You Can Do

Support seasonal closures of spider crab moulting aggregation areas to trawling
Choose spider crab from fisheries with documented non-trawl capture methods during moulting season
Back Marine Conservation Zone designations in areas where spider crabs aggregate annually
Engage with the Marine Stewardship Council to understand spider crab fishery certification standards