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  • Writer's pictureThe Wild Foodie

American Signal Crayfish: Where to find them and how to catch them

Updated: Aug 11, 2023

At this time of the year its starting to warm up and Spring is set in for good. The rising temperatures wake up more than the plants and trees in the spring, there is also movement at the bottom of our rivers.

Where to find and how to catch American Crayfish
American Signal Crayfish

Back in the 70’s, and to what I imagine would have been the theme tune to Jaws, a loud overbearing creature was heading this way, migrating (with the help of humans) from America.. No it wasn’t who you were thinking of!! But a breed of crayfish called the American signal crayfish. This crayfish was part of the food revolution that began in the late 70’s and was being imported to be farmed here in the UK. As fantastic a result as the pallets of British people waking up from post war rationing was, all of these imported new foods were brought in quickly and some 'accidentally' got released into the wild.. As a result, an unfortunate casualty of this mass immigration was our own white-clawed crayfish whose stocks have reduced by a massive 95%. Making it practically extinct except for a few places in the UK.

Moving forward to now.. What can we do about it!? Well not a lot. Although the Environment Agency have tried to hold back this storm (along with other damaging foreign species such as the Mitten crab – a Chinese and again very tasty imported species) there is simply nothing we can do. Apart from being voracious predators eating; plants, snails, small fish, fish eggs, invertebrates and even its own young they also carry a deadly plague that they themselves are immune to. This crayfish plague only affects other crayfish and is decimating populations of native white-claws across the country. Alongside the out-predation by this larger species.

Crayfish traps and pots guide
Crayfish Pots loaded with Crayfish

The American crayfish has used its cunning to spread but has also been helped along the way by other reckless crayfish farms, and perhaps a few individuals too. With an ability to cross land and huge numbers on their side signal crayfish have successfully invaded most parts of the UK. American crayfish can now be found in our rivers, lakes and ponds and in all parts of the UK, bar the furthest regions of Scotland.

The signal crayfish also digs burrows up to three feet long in river banks where each year it lays hundreds of eggs at a time, which is unfortunately leading to river bank erosion and changing the course of some rivers.

However, it is not all bad, encased in a tough shell and armed with two large pincers it looks and indeed tastes rather like a lobster or langoustine and this is why I love to eat them.. But let's get to it, how do you catch crayfish?

How to Catch Crayfish

To catch crayfish in the UK, there are specific guidelines to follow. Firstly, it is important to obtain a license before considering crayfish trapping (more on that below). These licenses are in place to safeguard native crayfish populations and prevent the further spread of this invasive species.

Select appropriate equipment for crayfish trapping. Mesh or wire traps must:

  • Be no longer than 600mm

  • Be no wider than 350mm at the widest point

  • Have an entrance no more than 95mm wide (unless fitted with an otter guard)

  • Have mesh no bigger than 30mm at its widest point

  • Have an Environment Agency issued trapping tag attached when in use

Choose traps or pots that meet legal specifications and are suitable for the UK waters. Illegal traps can catch other water loving species such as voles and otters. So stick to the rules.

Obviously, you'll need to use bait to catch a crayfish. Use baits such as fish scraps, meat, or cat food, and securely fasten or tie the bait inside the trap to prevent it from being easily taken away by the crayfish.

Identify suitable locations where crayfish are known to be present. Rivers, streams, and lakes are common habitats for crayfish. Speak to local anglers, environmental organisations, or fisheries management agencies to identify areas where crayfish are likely to be active.

Place the traps carefully in the water, ensuring they are securely anchored and positioned in areas frequented by crayfish. Take care not to block water flow or create hazards for other aquatic organisms. Remember, that your traps must be on the bottom to work.

Regularly check your traps. Typically, traps are checked every 24 hours to minimise stress on captured crayfish, but to also check the bait is still there, and harvest your haul. Remember to be careful when handling the traps, as crayfish can be aggressive and possess pinchers that can give a nasty nip.

If non-target species are caught, release them carefully back into the water to minimise harm.

Dispose of captured crayfish responsibly, adhering to proper procedures for dispatching and disposing of them in a humane and responsible manner. Remember it is illegal to release invasive crayfish back into the water once you have caught them (the native white-claw must go back).

For a more definitive guide on how to trap and prepare crayfish using pots and traps click the link.

Can you eat signal Crayfish?

American signal crayfish can indeed be eaten. In fact, they are often considered a culinary delicacy. The meat of the signal crayfish is generally considered delicious and similar in taste to lobster or langoustine.

Is it legal to catch crayfish in the UK?

Yes, it is legal to catch crayfish in the UK, but it is subject to specific regulations and licensing requirements. These regulations are in place to protect native crayfish populations, prevent the spread of invasive species, and ensure sustainable fishing practices. The exact regulations can vary depending on the region, water body, and specific crayfish species. It is essential to familiarise yourself with the local regulations and obtain a crayfishing licence.

Please check the rules and regulations of crayfishing as well as details on how to get a licence at the Environment Agency Website.

Where can you catch Crayfish in the UK?

In the UK, crayfish can be found in various freshwater habitats, including rivers, streams, lakes, and ponds. Here are some notable locations in the UK, where you can potentially catch crayfish:

where to catch crayfish in rivers
Crayfish in UK rivers

Rivers: Many rivers across the UK are home to crayfish populations. Some well-known rivers with crayfish include the River Thames, River Severn, River Wye, and River Tamar.

Lakes and Reservoirs: Numerous lakes and reservoirs in the UK support crayfish populations. For example, the Lake District in Cumbria, including lakes like Windermere, Coniston Water, and Ullswater, is known to have crayfish. Additionally, reservoirs such as Rutland Water in England and Loch Ken in Scotland offer opportunities for crayfish catching.

Canals: Canals, such as the Grand Union Canal, Kennet and Avon Canal, and Caledonian Canal, also contain crayfish populations.

Nature Reserves: Some nature reserves and protected areas in the UK actively manage crayfish populations and offer opportunities for crayfish trapping under strict guidelines. Examples include the Norfolk Wildlife Trust reserves, the Crayfish Conservation Trust reserves, and the Scottish Natural Heritage sites.

Local Fisheries: Certain fisheries across the UK allow crayfish trapping alongside fishing activities. These fisheries often have specific rules and permits regarding crayfish capture, so it is advisable to inquire with the fishery owner or management for guidance.

Note: If you are fishing multiple rivers and lakes, be sure to clean your pots between fishing trips to prevent the spread of any crayfish pathogens.

American Signal Locations in the UK

UK Signal Crayfish Locations Map
Signal Crayfish Locations in the UK

So where can you find and catch American crayfish in the UK? Signal crayfish have now spread far and wide. It is not hard to find a spot that is near to you that won't be teeming with these delicious invaders. If you have a pond and live near a river, then they might already be lurking closer to home than you might realise, as they can travel vast distances (for a little crustacean) over land. The signal crayfish is well established in England and Wales, especially in the south-east of England. They are not as prevalent in Scotland but several well-established populations have been recorded.

When can you catch Crayfish?

In general, crayfish trapping season in the UK typically aligns with the active months of the crayfish, which coincides with warmer weather when crayfish are more active. There is no national crayfish season as such. Just when you are most likely to catch them. Do check local rules though, as this may differ from location to location.

When is the Crayfishing Season?

The 'catching' season usually starts in spring or early summer and extends into autumn. April to November is when they are active, although they are most prevalent May onwards, and for as long as the weather is warm.

Understanding Signal Crayfish Behaviour to Catch Them

You want to catch crayfish? Think like a crayfish.. Understanding signal crayfish behavior can be helpful when devising strategies to catch them. There are many aspects of signal crayfish behavior that can be utilised to sharpen up your trapping efforts:

Nocturnal Activity: American Signal crayfish are predominantly nocturnal, meaning they are most active during the night. They tend to emerge from their burrows and forage for food under the cover of darkness. Setting traps during the evening or overnight can increase the chances of capturing crayfish.

Habitat Preferences: Signal crayfish often prefer areas with cover, such as rocks, logs, or submerged vegetation. They use these structures as shelters and for protection. Placing traps near or within these types of habitats can attract crayfish and increase trapping success.

Feeding Behavior: American crayfish are opportunistic omnivores, consuming a variety of food sources. They feed on plant matter, invertebrates, small fish, and carrion. Baiting traps with smelly food items like fish scraps, meat, or cat food can attract crayfish and entice them to enter the trap.

Aggressive Nature: Signal crayfish can exhibit territorial and aggressive behavior. They are known to defend their burrows and may engage in aggressive interactions with other crayfish. Utilising multiple traps in close proximity can capitalise on their territorial tendencies, increasing the likelihood of capturing crayfish.

Burrowing Behavior: American crayfish are skilled burrowers, creating complex tunnel systems in the banks of water bodies. When setting traps, positioning them near burrow entrances or along burrow pathways can intercept crayfish as they move in and out of their shelters.

Seasonal Movements: During certain seasons, such as late summer and autumn, American signal crayfish may undertake seasonal migrations. They can move upstream or downstream in search of suitable habitat or for breeding purposes. Identifying these migration routes or focusing trapping efforts near areas of potential migration can enhance catch rates.

By incorporating knowledge of signal crayfish behavior into trap placement, baiting strategies, and timing, you can increase the effectiveness of your crayfish-catching endeavors, catch more, and catch more-more quickly.

American Signal Crayfish Identification

As we have discussed, the American signal crayfish (Pacifastacus leniusculus) is an invasive species in the UK, and there the now rare native species called the white-clawed crayfish. The American crayfish can be identified by the following characteristics:

Size: American signal crayfish are generally larger than the white-clawed natives. They can grow up to 16-20 centimeters in length, including the claws.

Colour: They have a variety of colourations, ranging from olive green blue to dark brown or reddish-brown. The colour can be mottled or uniform.

Claws: The claws of American signal crayfish are robust and are bright red on the undersides, they flash there red claws when threatened, hence the name 'signal' crayfish. The claws can also have dark bands or spots on them.

Spines: They have prominent spines on their backs, particularly on the sides of the carapace (the hard shell covering their body). The spines can be quite sharp.

Rostrum: The rostrum, which is the extension of the carapace between the eyes, is generally straight or slightly curved downward in American signal crayfish. It can have small spines or bumps along its length.

Abdomen: The abdomen of American signal crayfish has six abdominal segments, each with a pair of swimmerets (small appendages used for swimming and reproduction). To identify the gender of the crayfish (if that's your thing), the last pair of swimmerets in males is generally larger and more elongated than in females.

How the Signal Crayfish differs from the White-Clawed Crayfish

The white-clawed crayfish, native to the UK, is smaller in size, has a uniform colour, and possesses slender claws with white or pale appearance. Its rostrum is straight or slightly curved downward, and it has six abdominal segments with short swimmerets, its also much smaller than the American signal when fully grown. In contrast, the invasive American signal crayfish found in the UK is larger, exhibits variable colouration, has robust claws with red undersides, prominent spines on the back, and a straight or slightly curved rostrum.

Native White-Clawed Crayfish
Native White-Clawed Crayfish

Learn how to identify the white-claw as, if you are lucky enough to find them, they are protected and must be released back into the water. Additionally, if you do find white claws, then it is highly unlikely you will find American crayfish in the same place as they will out-predate and kill off the natives.

Other Non-Native Crayfish in UK Rivers and Lakes

In addition to the American signal crayfish (Pacifastacus leniusculus), several other non-native crayfish species have been introduced and have unfortunately, become established in the UK, including:

  1. Red Swamp Crayfish (Procambarus clarkii): Originally from North America, the red swamp crayfish has been introduced to certain areas in the UK. It is known for its vibrant red coloration and aggressive behaviour.

  2. Turkish Crayfish (Astacus leptodactylus): Native to southeastern Europe and western Asia, the Turkish crayfish has been established in a few locations within the UK. It is larger than the native white-clawed crayfish and has distinctive long, thin claws.

  3. Noble Crayfish (Astacus astacus): The noble crayfish, native to parts of Europe including Scandinavia and Eastern Europe, has been introduced to a limited number of sites in the UK. It shares similarities with the native white-clawed crayfish but tends to be larger and possesses more robust claws.

  4. Spiny Cheeked Crayfish (Orconectes limosus): This species, originally from North America, has also been introduced to certain areas in the UK. It is known for the spines on its cheeks and its ability to rapidly reproduce, like the signal crayfish, furthering its ability to out-compete native crayfish species.

It is important to reiterate that these non-native crayfish species, including the American signal crayfish, are considered invasive and pose significant threats to native crayfish populations and freshwater ecosystems in the UK. Conservation efforts and management strategies are in place to mitigate their impact and protect the native crayfish species. If you catch them and positively identify them as such, they should not be returned to the water.

American Signal Crayfish Facts

  • The American crayfish is now the dominant species of crayfish in the UK

  • The female breeds from the age of about two when it is 40mm long.

  • She breeds once a year and averages approximately 275 eggs.

  • The orange eggs are fertilised by the male in October/November.

  • They are carried by the female folded within her tail until May when the young are released - if they can escape her jaws.

  • The American crayfish is bigger and more aggressive than the native crayfish.

  • They are less fussy in what they eat, more successful and rapidly colonise new areas.

  • The signal crayfish carries a fungus which is fatal to native crayfish.

  • They can live up to 12 years (unless we can halt this prematurely!).

As previously discussed, the signal crayfish’s most endearing characteristic is.... Its flavour! Crayfish have a rich tender luxurious pink meat that is outrageously moreish! The Swedes go mad for the crayfish season and throw big dinner parties to gorge on this little crustacean with the accompaniment of vodka. In the UK they tend to end up in a crayfish cocktail however, there are many other combinations including Valentine Warner's amazing dish that includes cobnuts, cheese and a hot oven!!

Summing Up

In conclusion, catching crayfish in the UK requires a little planning and forethought. You will need to consider the location, methods of catching, and timing. Ensure compliance with local regulations and be responsible, don't go using an illegal trap that could accidentally drown a bird or mammal. Remember to get a licence first!

When it comes to 'where to catch crayfish' in the UK, they can be found in various freshwater habitats, including rivers, streams, lakes, ponds, and canals. Conducting research, consulting local anglers and online resources (see above), can provide valuable insights into the specific locations where crayfish populations are present.

Crayfish are most active when it is warm, so fish for them after spring has warmed up, and before the first frosts.

Before considering crayfishing, it is crucial to use appropriate equipment such as UK legal mesh traps to prevent the capture of more friendly wildlife. Properly bait the traps with fish scraps, meat, or cat food.

Don't just leave your traps soaking and forget about them. Although invasive and destructive, they are a living creature, a living creature that deserves to be handled and despatched with care. So check your traps every day and don't take more than you need.

Most importantly, don't forget to enjoy yourself, it is great to spend time by the river, but spending time by the river and catching a delicious lunch... Well, that is why we do it.

Note: Please check the rules and regulations of crayfishing as well as details on how to get a licence at the Environment Agency Website.

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