Catching crayfish: protect native ones, recognise invasive ones
Crayfish are easy to find in streams and lakes and, well cooked, are a valuable source of protein. But native species such as the noble and stone crayfish are rare and strictly protected. Introduced American crayfish such as the signal, spiny-cheek or red swamp crayfish displace them and spread crayfish plague. This entry shows how to tell them apart, how to pick up crayfish without getting pinched, kill them at once and cook them thoroughly – and why live invasive crayfish must never be transported.
- 1–2 hours at dusk
Eenvoudig uitgelegd
Crayfish look like little lobsters and live under stones in streams and lakes. If you lift a stone slowly, the crayfish shoots away backwards with a flick of its tail.
There are two groups: our own crayfish, the noble crayfish and the stone crayfish, are now very rare – they are protected, and you leave them alone. And there are crayfish brought over from America. They carry a disease, crayfish plague, that kills our crayfish.
With permission you may catch the introduced crayfish, and in a real emergency they make a good meal when cooked. But you must never carry them anywhere else alive. If you are not sure which crayfish it is, put it back exactly where it was.
Hoe het werkt
Crayfish are nocturnal. During the day they sit in hollows under stones, among roots and in holes in the bank; at night they walk across the bottom looking for food. With a headlamp you then see them in the open in shallow water – their eyes sometimes briefly shine.
A frightened crayfish always flees backwards with a strong flick of its tail. Knowing this, you hold your hand or a container behind it and shoo it from the front. If you grip it on the back shell behind the claws, it cannot pinch.
The species are told apart mainly by their claws and colouring. The introduced signal crayfish has a striking pale patch at the claw joint – hence its name. Our native crayfish do not have this patch.
Waar het om gaat
Identification is the most important thing. A native crayfish eaten by mistake is a loss for a threatened species. So the rule is: when in doubt it is a native crayfish, and it goes back into the water – at exactly the same spot.
Introduced crayfish are not transported, kept or put into another body of water alive. EU law forbids this because otherwise crayfish plague spreads further. They are killed where they are caught, fastest in rolling boiling water that covers them completely.
Only thoroughly cooked crayfish are eaten: the shell is red all over, the flesh white and firm. Dead crayfish you find and crayfish from polluted water are left alone.
Veiligheid: hier moet je op letten
Crayfish plague can be carried from one body of water to the next on wet boots, containers and hands. So let everything dry thoroughly before going to another water.
When turning stones in a stream, do not go into deep or fast water, and in cold weather do not work for long with wet hands and feet.
Catching crayfish falls under fishing law. Many waters issue their own permits for invasive crayfish – without permission it remains emergency knowledge.
Stap voor stap
Check the law and the water
Only someone with permission from whoever holds the fishing rights may catch crayfish – some waters issue it specifically for invasive crayfish. Without permission, only in genuine danger to life. Avoid nature reserves and waters where native crayfish live.
- 1
Check the law and the water
Only someone with permission from whoever holds the fishing rights may catch crayfish – some waters issue it specifically for invasive crayfish. Without permission, only in genuine danger to life. Avoid nature reserves and waters where native crayfish live.
- 2
Search at dusk
Walk along the bank with a headlamp and shine it into the shallow water. Crayfish then sit in the open on the bottom. During the day you find them under flat stones and among roots.
- 3
Grab from behind
Lift a stone slowly from the side away from you. Grip the crayfish with thumb and forefinger on its back shell behind the claws – it cannot reach you there. Alternatively hold a container behind it and shoo it in from the front with a small stick.
- 4
Identify the species
Look at the claws. Signal crayfish: smooth, large claws with a pale white-turquoise patch at the top of the joint. Spiny-cheek crayfish: red-brown stripes on the tail, small claws with orange tips. Red swamp crayfish: deep red with spines on the claws. Noble crayfish: red claw undersides, no pale patch. Stone crayfish: small, brownish, no patch.
When in doubt it is a native crayfish: put it back at once.
- 5
Put native crayfish back at once
Put native crayfish back carefully at exactly the same spot. Never move them to another body of water.
- 6
Kill invasive crayfish at once
Do not carry invasive crayfish away alive. Rolling boiling water kills fastest: drop the crayfish in head first, one at a time, so it is fully submerged. The water must keep boiling as you do so.
- 7
Grondig gaar koken
Keep cooking the crayfish for at least a few minutes until the shell is red all over and the flesh is white and firm. The tail meat is the main part eaten; remove the dark gut thread.
- 8
Dry your gear
Let boots, containers and gloves dry thoroughly after catching before you go to another body of water. That way you do not spread crayfish plague.
Veelgemaakte fouten
- Mistaking native crayfish for invasive ones
- Carrying live crayfish away in buckets
- Putting crayfish into another body of water
- Putting them into water that is not at a rolling boil
- Eating them undercooked
- Eating dead crayfish you found
Kort overzicht
Materiaal
Hoofdlamp / zaklamp
Crayfish are active at night
Bucket with a lid or a sealed bag
Never transport live invasive crayfish – only ones already killed
Metalen pan (roestvrij staal, aluminium, titanium)
For cooking in rolling boiling water
Heet – gevaar voor brandwonden door heet water of stoom.
Stevige werkhandschoenen
Against claws and sharp stones
Draag bij contact met overstromingsslib of chemicaliën ook waterdichte handschoenen.
Geschikt voor
- Streams, ponds and lakes with a stony bottom
- Longer emergencies by water
- Waters where invasive crayfish are known to occur
Niet geschikt voor
- Waters with native crayfish – catch nothing there
- Nature reserves
- Snel, diep of koud water waarin je zou moeten waden
- Water that smells of sewage or has algal blooms
Voorwaarden
- Genuine danger to life – or permission from whoever holds the fishing rights
- A fire or stove for cooking
- Safe footing on the bank or in ankle-deep water
Veiligheid
- Only eat crayfish freshly killed and thoroughly cooked. Never eat dead crayfish you have found or crayfish from polluted water.
Hoe het werkt
Crayfish hide under stones and roots during the day and forage at night. If you lift a stone slowly, you see the crayfish flee backwards – with a flick of its tail. So you grab from behind or hold your hand or a container behind it. Species can be told apart mainly by the claws: introduced signal crayfish have a pale patch at the top of the claw joint, native noble crayfish have red claw undersides without that patch.
Voordelen
- Easy to find and catch
- Lots of protein
- Catching invasive species relieves native crayfish
Nadelen
- Risk of confusion with protected species
- Little meat per animal
- Risk of spreading crayfish plague
- Prohibited without permission
Achtergrondkennis
Vakinhoudelijke achtergrond
Central Europe used to be rich in noble crayfish. Since the 19th century, crayfish plague, a pathogen that American crayfish carry unnoticed, has wiped out most populations. Signal, spiny-cheek and red swamp crayfish are therefore on the list of invasive species of Union concern: they may not be kept, transported or released.
The native species are protected under the European Habitats Directive. For emergency food this means: invasive crayfish are a good source of protein, native ones stay untouched.
Varianten
- Crayfish trap with permission
- Where fishing-rights holders encourage catching invasive crayfish, approved traps are often issued. They are set according to local rules and checked daily.
- With a bait line
- A piece of fish scrap on a line, without a hook, attracts crayfish. They hold on to it and can be drawn slowly to the bank.
Veelgemaakte fouten
- Mistaking native crayfish for invasive ones
- Carrying live crayfish away in buckets
- Putting crayfish into another body of water
- Putting them into water that is not at a rolling boil
- Eating them undercooked
- Eating dead crayfish you found
Grenzen en risico's
- The identification features are simplified; when in doubt always put it back
- No details on where which species occurs – this changes
- Geen juridisch advies
Materiaalalternatieven
Afgeleid van materiaaleigenschappen: een vervanger moet alle relevante eigenschappen hebben. Let op de opmerkingen bij de vervanger.
- Hoofdlamp / zaklamp
- Mobiele telefoon (De accu loopt bij kou en bij continu gebruik van scherm en GPS snel leeg.), Lantaarn op batterijen / led-lamp
- Bucket with a lid or a sealed bag
- Enkelwandige roestvrijstalen fles (Verhit alleen enkelwandige flessen zonder verf of plastic; haal de dop eraf voordat je verhit.), Dubbelwandige geïsoleerde fles (Nooit rechtstreeks verhitten.), PET-fles (helder, max. 2 liter) (Niet verhitten en niet in een vuur zetten.), Voedselveilige waterjerrycan (Gebruik alleen bakken en jerrycans die nooit chemicaliën of brandstof hebben bevat.), Gebruikte chemicaliën- of brandstofverpakking (Nooit voor drinkwater of voedsel – resten zijn niet betrouwbaar te verwijderen.), Gegalvaniseerde emmer (Niet verhitten: de zinklaag kan bij verhitting schadelijke dampen afgeven.), Waterdicht doosje of zakje, Luchtdichte, voedselveilige voorraadbus (Vul alleen als de bak schoon en helemaal droog is. Gebruik nooit bakken waar eerder chemicaliën in zaten.), Voedselbak die dieren niet open krijgen (Waar bepaalde bewaarbakken verplicht zijn, gebruik dan alleen goedgekeurde modellen – controleer de lokale regels.), Klein blikken busje met deksel (Brand gecoate of gelakte bussen eerst buiten uit.), Opvouwbare jerrycan of waterzak (Beschermen tegen scherpe voorwerpen.), Voedselveilige waterzak (Alleen voor drinkwater gebruiken, nooit voor chemicaliën of brandstof.), Fermentatiepot of gistpot (Gebruik alleen voedselveilige bakken van glas, voedselveilig geglazuurd aardewerk of voedselveilig plastic – geen metalen bakken voor zuur eten.), Hersluitbare voedselzakjes (Gebruik alleen zakjes die bedoeld zijn voor voedsel; gebruik ze niet met kokend water, tenzij de fabrikant dat uitdrukkelijk toestaat.)
- Metalen pan (roestvrij staal, aluminium, titanium)
- Enkelwandige roestvrijstalen fles (Verhit alleen enkelwandige flessen zonder verf of plastic; haal de dop eraf voordat je verhit.)
Resultaten komen uitsluitend uit gestructureerde items. Er worden geen geïmproviseerde instructies gegenereerd.
Bronnen (6)
- European Parliament and Council of the European Union (2014): Regulation (EU) No 1143/2014 on the prevention and management of the introduction and spread of invasive alien species · Invasive species of Union concern may not be kept, transported or released
- Europäische Union – EUR-Lex (2016): Durchführungsverordnung (EU) 2016/1141 zur Annahme einer Liste invasiver gebietsfremder Arten von unionsweiter Bedeutung · Signal, spiny-cheek and red swamp crayfish are on the Union list
- Council of the European Communities (1992): Council Directive 92/43/EEC on the conservation of natural habitats and of wild fauna and flora (Habitats Directive) · Protection of native crayfish species (noble, stone and white-clawed crayfish)
- Bundesrepublik Deutschland – Bundesministerium der Justiz (gesetze-im-internet.de) (2012): Verordnung zum Schutz von Tieren im Zusammenhang mit der Schlachtung oder Tötung und zur Durchführung der Verordnung (EG) Nr. 1099/2009 des Rates (Tierschutz-Schlachtverordnung – TierSchlV) · Crustaceans may only be killed in strongly boiling water that covers them completely
- Freistaat Bayern – Bayerische Staatskanzlei (gesetze-bayern.de) (2008): Bayerisches Fischereigesetz (BayFiG) · Fishing and catching crayfish only with permission of the fishing-rights holder
- Land Niederösterreich – Rechtsinformationssystem des Bundes (RIS), Landesrecht (2001): NÖ Fischereigesetz 2001 · Crayfish fall under fishing law