Things You Need To Know About SIGNAL CRAYFISH!
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- เผยแพร่เมื่อ 23 ส.ค. 2024
- A simple but fact filled video about the Signal Crayfish, including their diet, how and when they breed, where they are found and much more.
If you have seen a crayfish in the UK in the last 15 years, the chances are it likely that it would have been a signal crayfish. These were introduced from north America to various sites in this county in the 1970s as a species for farming, but of course, they escaped into the wild and were probably deliberately released by people who wanted to eat them. Unfortunately, Signal crayfish are larger than and spread a disease that is fatal to the native white claw crayfish and they have now almost gone extinct here.
Signal crayfish grow to measure up to 18cm in length and have 2 powerful claws. These are bright red on the underside in adult animals and have a noticeable bluey white patch on the upper-side of where their claws hinge. Alongside their claws crayfish have 4 pairs of smaller legs for walking and two long antennae that protrude from the front of their heads. Around their mandibles they have 3 pairs of leg like limbs called maxillipeds which they use to handle food and apparently stone, but also to keep water moving through their gills. They have abdomens which are made of 5 segments and a flattened tail at the end of their bodies. Males grow larger than females and usually have larger more prominent claws. Crayfish moult several times as they grow and when this happens they are able to completely regrow limbs that they may lose whilst fighting or to predators.
Signal crayfish predominantly live at the bottom of fresh watercourses, including in lakes, ponds, rivers and streams. They can swim, especially when threatened by folding their bodies up and propelling themselves backwards but they usually move by walking along the bottom, although they will sometimes climb the bank and have even been seen emerging from the water to get food from above the waterline. They are mainly nocturnal but during the summer time it isnt unusual to see the larger individuals out in the open.
They are opportunistic omnivores and will eat everything from vegetation and decomposing material to small fish, fish eggs, invertebrates and they will even eat each other if food supplies become scarce. Unfortunately this can have a knock on effect on the waterways in which they live as they can reach such a density that they strip the bank and bottom of the habitat almost completely bare.
Alongside their demand for food, Signal crayfish also cause harm to habitats by creating extensive interconnecting burrows up to 2 metres deep into the bankside, sometimes leaving it looking like a sponge and susceptible to erosion and collapse.
Signal crayfish are prolific breeders. In the Autumn large males hold territories and then attempt to seduce passing females by trying to pin them to the bottom. If successful, they pass over a pouch of sperm and let the female leave. She will then go to a sheltered spot and lay between 2 and 400 eggs which she fertilised with his sperm before attaching them to the underside of her body. She will carry these eggs until Spring when they hatch. The young crayfish, once free swimming leave their mother and become independent straight away. It takes signal crayfish 2 to 3 years until they are able to breed but as they can live for up to 20 years, they have the potential to produce lots of young in their lifetimes.
Signal crayfish are native to the united states and Canada but have been introduced across Europe and are now found in at least 25 European countries. They are also found across Russia, in some parts of northern and east Asia and in south Africa. People often ask if they can be controlled in any way and the answer is no, not without destroying the rest of the habitat for a period of time at least. In the UK, the best thing people can do to protect native crayfish is be very careful that they are not moving signal crayfish or the disease that they carry from one place.
#crayfish #wildlife #nature
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Thank you for watching this video and taking a look at the comments!
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Cheers.
Dear Liam, You did an excellent job of doing what so many TH-camrs tend to stretch out into twelve minutes of redundancy. You gave the whole story in a quick video. This was considerably better than average.
The other good thing you can do to reduce signal crayfish numbers is to catch and eat them...they're pretty tasty!
You need a licence to do that. Tbh honest i would have thought it would be better too not need one to encourage the eradication of them.
@@6panel300depends on where you are. My shellfish license is $10/year....and I catch 100 signal crawfish daily from my river in my yard.
But I’m in the US.
". . . and apparently stones" -- hilarious! Great piece. Thanks.
Thanks Liam. I knew very little about the Signal Crayfish except that it is an introduced species, larger than the native Crayfish. Their breeding habits sound a lot like those of a few men I know ! 😅
I remember seeing (native) crayfish in the rivers Aire and Wharfe many years ago when I was young but I have no idea whether they still exist in those rivers. I look for them when I'm by rivers and streams in that area but haven't seen a crayfish of any kind.
Very informative….👏
Thank you for this video, I don't know what it is about Signal Crayfish but they give me the creeps. 🙃
When you pointed some out to me in a river last year, it got me wondering about the times I had gone past rivers while out and about and not spotted them as they tend to be well hidden like 2:39 . Thanks and great video!
You didn't mention they are DELICIOUS with garlic sauce
fascinating. some awesome information here. great work.
Thanks for that Liam. Fascinating as always 👍
Any chance of doing a video about Sparrowhawks?
Yes, they are on my list and I am looking forward to making that video so stay tuned.
@@AShotOfWildlife 😃 🙂 excellent. Can't wait.
I love Sparrowhawks. So elusive. Hardly any videos about them. Look forward to it. Thank you for doing this channel. 👍.
@@dazmick1111 cheers!
Well never even heard of them before. Now you have expanded an ol' girls wild life knowledge which is great . Thank you.
Love this! Thank you for continuing with the invertebrates.
Cheers! plenty more lined up for the future too :)
catch and cook.
Wonderful as ever! I find that with these short fact file films it's good to watch twice, after all they're only 5mins or so and its nice if some of the information actually goes in.. Nice one Liam! ⭐👍
Hi Liam brilliant video again loved the filming of the crayfish very good close up of them interesting information about them I had crayfish in my tropical fish tank one blue and one green it’s fascinating to see them shed their skin keep up the amazing work and videos Bernard
you could also help our native crayfish by eating the signal ones as much as possible! and people say my humor is dark
A very similar story to the effect the grey squirrel had on our native red squirrel ☹
Squirrel tastes good also.
Thank you Liam another great and informative video.
You are so lucky to have streams with so much life. I live near a lovely stream but it is dead. No life in it at all, not even a minnow 😢.
Love your videos 👍🏾
Nothing? What happened to it?
@@NaCreagachaDubha I would love to know, not seen anything in there for 20 yrs or more. 😢
Thanks + we do have white crayfish here in Nuneaton, Warwickshire, though I don't recall seeing any!
Thanks Liam, informative as ever.
I live in California and catch these in streams above a lake nearby (Fresno area). They're big and meaty, and some larger claws can even have a good amount of meat in them, but I find they're not as tasty as red swamp crays in general. Still though, consider catching and eating these little bugs en masse as a way to help cull the population!
Great video. Love catching the monster signal here in the P.N.W
Thank you. I am not sure where P.N.W is?
@AShotOfWildlife
Washington Oregon and a couple others. Our season ended a few days ago here in Washington
Nice to watch videos that are full of information and great facts A lot of other vlogs are full of boring repetitive dialoge
Keep up the good work ..see you on your next one ..
Brilliant, thank you Liam.
Thanks Liam, very interesting video🙏
My local canal is full of them at the moment, they will even eat sweetcorn so fishing isn’t currently possible…it was fine until July and now they have gone mad. They hit your bait within seconds🤷🏼♂️
It's kinda like knowing how to read and write so you eat your friend who is just learning how to speak
Signal Crayfish are rampant in north yorkshire rivers and streams, Private lakes where they are stocked for food. I can catch 2 full bucket fulls in 2 days in rivers and streams.
Crayfish curry! Used to pull them out at Silsden. They are so easy to catch with a makeshift trap and an old tin of cat food. Is that how you do it?
@@geoffreystuartboxx there are also at Horton Bank Country Park.
Hi Laim. You might be interested in the TH-cam posting. The corncrake and the croft. Some good footage of corncrakes.
Thanks, ill check it out
thank u so much for your great videos keep up the good work
Fascinating creatures..
Respect for life moves in both directions
Just hire a few Cajuns. They look a little bigger than the crawfish in Louisiana, but that means more meat in the tails.
Great video Liam! The UK situation and history of the Signal Crayfish is similar to how it has been and still is in Sweden too. Greetings and have a good weekend! // Bertil.
And Finland too 😢
Thanks for another great video… I used to trout fish many years ago and always remember meeting Roger Daltrey when fishing with my father at his Lakedown Fishery in East Sussex. He showed me some of these Crayfish he had at his fishery where I think he was breeding them. That must of been well over 20 years ago and I hadn’t realised they were an invasive species back then. I wonder what natural controls there are in the waterways to manage their numbers. I.e. would say a large chub be able to prey on them?
Oh the problem of invasive species.
I pray for the day when we finally eliminate the bloody things.
Eat more of them...
They are America’s best crawfish, native where I am.
Great underwater footage
Get it!!!!!!
Such a cool animal-it’s just a shame they are so harmful for our rivers and canals
Tasty, too.
@@MirlitronOneWow, so very cruel.
@@prettynoose888 clearing out a harmful alien species and getting a nice snack, don't see any issue there!
@@itzkingcringe But this is the attitude that caused the problem in the first place. Listen to what is said between 0:20 and 0:34 in the video. It's human greed and peoples unsatiable huger that caused the problem in the first place. There has to be a humane way they can remove the crayfish from the waterways. If humans can't learn to control their stomachs and greed, we are going to destroy the environment.
@@prettynoose888they are native where I am. I’m so cruel I eat about 100 per day that I catch in my river on my property. 🤣
This gave me the creeps.
Pre historic.❤
They are cute
We should be allowed to freely catch these little buggers though it probably wouldn't stop their advance. Thanks for another cracking video, mate!
I've spotted some in a local canal last year. I checked this year and probably because of cold weather, they haven't been out as much. I wish I could help out the white-clawed crayfish but I'm only one person! 😭
WHEN I WAS A KID I USED TO CATCH THESE AND SELL THEM TO THE LOCAL CHINESE RESTAURANT FOR 10P EACH EASY MONEY
Taste nice
Why don't the Environment Agency give us free traps and recipe books ?
Well, there are a couple of reasons for this:
The crayfish plague which is killing the native species can be spread on damp crayfish traps so there is a risk that people trying to trap signals may spread it to new sites. Traps also favour catching larger crayfish- which reduces the competition and predation on smaller crayfish, basically resulting a population boom.
Eat them
Awesome
These are prolific throughout my local waterways in Hertfordshire. They have totally decimate the river Colne. People are oblivious too the problems they cause.
I am here to help heal our home
I climbed the tree
This whole world is a fish bowl to me
I saw one of them on the bank of the river Kennet, it was just walking as if it lives on land 😂
Are they safe to eat?
Our local canal is full of them
If birds and bees die we also die
If the waters die
We die
Water is life
It's all drinking water for our ecology
Even if your not drinking it
How does one get a permit and land owners permission so fish them?
Come to to the US, I’ll give you permission to trap them out of the river on my property.
Plenty to spare...
Illegal to put back if caught when fishing, I've had to bash many of these on the head with a big rock!
Good to know. Won't feel guilty about eating them then.
Waste of food....
Can you eat them?..
Yes.
I want to eat the tails
Are the edible?
They are edible but in Norfolk (where I live) trapping them.isnt allowed.
@@AShotOfWildlife i thought it would be a good way of controlling their numbers.
👏👍🤘
🦞
We Arthropods grow to about 3 meters tall but have the potential to be at least 36 ft tall like the mammals
Naturally weaponized
As an arthropod myself I am horrified
That you would want crayfish to eat mammals
Remember the mouse ate the snake
Till the snake ate the mouse
Everything evolves
And remembers
Earthlings are rarer than gold
My friends are not food
arthropods will always out number humans
And evolve faster than a human can too
When will you start to see the crays are of our own blood
We share the same potential
👍
Looks like Dr Zoidberg.
The only good thing about them is they taste good.
You neglected one important detail, they are delicious.
Catch them and eat them
Can u eat them 😋
Yes
Please do, they taste good and are invasive to the UK.
Yes, but it depends where you are in the country if you are allowed to catch them.
Anything with 2 eyes is potentially you
One question not address: are they related to lobsters? And in turn related to roaches?
Yes and no, they are similar in a lot of ways but crayfish and lobsters belong to 2 separate families that would have separated a very long time ago.
@@AShotOfWildlife that’s so interesting. I always wondered about that, thanks!
It’s funny because before a few years ago I had never seen a crayfish in my life. Then one day I was walking on the trail near my home and I saw something moving in the grass. I went up to see it and had no idea what it was. So I asked someone who was passing by (lol who looked at me like I had ten heads for not knowing this already, lol) and he said it was a crayfish. It was missing one claw, so it was an interesting sight. They look so much like lobsters (to me) but much smaller, and I’m sure many would not agree that it looks anything like a lobster at all, but to me it did, lol 🤷🏻♀️. So now, to learn a bit more about it is very interesting, thanks!
🤗 promo sm
Best thing you can do is eat them. They live under stones, the bigger the stone, the bigger the crayfish.
Crayfish are ace. I've been turning rocks over in the river looking for them since I was a kid, There's loads.
I've always wondered what them holes were and I'd never have thought they were crayfish burrows. That's good Dad knowledge that.
If you are in the UK by law If you find signal crayfish you have to kill them and if they are native crayfish you have to leave them alone. But to trap signal crayfish you need a licence.
I live in southeast Louisiana, and I can dig up crawfish in my backyard. They will burrow and leave a mound that looks like a tiny volcano.
Not for human consumption