The Noble Crayfish

The Noble Crayfish (Astacus astacus) is the only freshwater crayfish native to Finland - a slow-growing, long-lived decapod crustacean (not a fish, but treated as one in Finnish angling tradition) that has shaped lakeside summer culture for centuries. Adults are a deep reddish-brown to dark green-brown above with a paler underside; the claws are robust, granulated, and - most importantly for identification - red on the underside. The rostrum bears two pairs of distinct ridges, and the tail segments lack the white-tipped claws and smooth blue-tinted carapace of the invasive Signal Crayfish (Pacifastacus leniusculus) it is so often confused with.

In Finnish it is rapu, and few foods are more woven into Finnish summer than the boiled crayfish of late July. The season opens at 12:00 on 21 July by national fisheries law, and the weeks that follow are the high ritual of rapujuhlat - crayfish parties on lakeside terraces with bibs, candles, dill-laden boiling broth, dark rye bread, butter on toast, and small, ice-cold glasses of schnapps drunk with ceremonial little songs between every claw. To catch your own, by trap or by hand from a boat at dusk, is one of the deep summer rites of the Finnish lakeland.

Ecologically, Noble Crayfish are nocturnal benthic omnivores of clear, cool, well-oxygenated freshwater. They burrow into clay banks, hide under stones and submerged timber by day, and forage at night for invertebrates, plant material, carrion and the occasional dead or weakened fish. Mating occurs in autumn; females then carry eggs in berry under the abdomen all winter, releasing tiny juveniles in late June. Wild Finnish stocks have been devastated since the 19th century by crayfish plague (Aphanomyces astaci) - a water-mould carried, asymptomatically, by the introduced Signal Crayfish - and the species is listed as Endangered (EN) on the Finnish Red List. Many southern lakes today hold only Signal Crayfish; recovering Noble Crayfish populations exist, but they are isolated, plague-vulnerable, and managed with care.

Noble crayfish (rapu, Astacus astacus) are not caught on a rod - they are taken in baited traps (mertaa) lifted by hand or boat after sundown. The Finnish season is tightly regulated: trapping is legal only from July 21 at noon through October 31, with a 10 cm minimum (carapace plus tail), and the warm August nights are the heart of the ritual. Most catches happen on the second or third lift after dusk, and a good evening is as much about the sauna and dill-boiled crayfish afterward as about the haul itself.