Warren,

good thinking mate, but how many chub do you think it would take to keep a Crayfish population of 1 million in check.

Carp are meant to love Crays as well but they aren't preventing the onslaught or even holding it up.

Worth investigating though, I'd rather catch a big Chub than a Bream any day. See you at the fishin.

Bspit

Warren it is a good idea, but it never worked on the Kennet. lots of chub, lots of barble, lots of carp, lots of crayfish!

HI Warren,

I think that we have to use chub,catfish,nets and cages as a package of ways to control a crayfish population...

But we need action !!!

I cant say that i have heard of a water that is actually doing anything about the crayfish...

Korda has a few traps, but we need lots more traps and a porper strategy to keep the numbers down..

Early part of the season the crayfish where nowhere to be seen in 14ft of water in silt, now im getting baits taken off in hourse in 14ft of water they are getting out of hand on places like Korda, once they get a hold its even harder to get the population down....

I too don't think the chub idea would work. Let's face it carp will munch there way through a lot of crays and a few more chub are not going to have much if any impact. However it is possible to control numbers, but I doubt you will ever achieve total eradication.

It is possible to control numbers by the use of Fyke nets (need EA permision). My own water has been successful in this respect. It takes some effort and cost but can be done (at least for Turkish). We have suceeded in reducing numbers so that they are only a minor irratation in the summer, whereas two years ago you couldn't keep a bait in the water for more than twenty minutes irrespective of wether it was netted, air dried, or an anti cray mix bait. They took the lot. Currently the levels are OK, and sort of in balance, but the fishery owner is ready if they get out of hand again. Try discussing the problem with the EA they are normally pretty helpful.

Cy.

Warren,

I was not knocking your suggestion, it is a perfectly valid point, but I do think there are problems associated with it that concern me and although it maybe be possible to control cray fish numbers with chub these other issuess I think need thinking about.

First, it is not generally a good idea to introduce one alien species to control another. Chub are alien in the sense that they are not normally found in lakes (I assume you are talking about lakes or at least enclosed waters). I know that of course chub can and do survive quiet well in lakes, indeed I have caught them in Wraysbury 1, but it is not there natural environment.

Second, you would have to introduce large numbers to have any effect. It would be difficult to get the numbers of the size required and I am sure there would also be problems getting the required permission from the EA.

Third, there is the nusiance problem to carp anglers which should not be underestimated.

Fourth, if the crays are brought under control what would the chub eat then, similar food to the carp most likely and that could have an impact on the carp.

Overall all I am saying is that netting/trapping is a proven method of control and has minimal environmental impact. Introduction of chub is not proven (to my knowledge) and has possible adverse affects.

Just my views, not a dig mate.

Cy.

Mr Yates,

I think you probably have the answer, I have obtained permission to remove them from our water so I guess with some work in the closed season we may see a reduction in problems next season.

Warren, nothing wrong with a bream or two except the slime, or a shoal of them ploughing through your lines all night.

Cheers

Bspit

Biological control rarely works and often causes more problems than it solves and as Cy has pointed out trapping would be the best method to employ. Just make sure you have non natives in your water and you have permisson from the relevant authorities (EA, EN), and that the crayfish are killed not dumped elsewhere as not only is it illegal but completely irresponsible.

I can't stress enough to people seeking to control crayfish to check the species in there aren't our native species. I have said before that some of the anglers on a local water stamp on natives because they read the comics and assume all crays to be bad. This water (Brasside in Durham) was made a SSSI because of the natives in there.

So do your research people.

Filthy.

What would be the consequences of the 'native species' being wiped from our waters?

Is this yet another political paper exercise to concern someone over? Would our waters really suffer through their lack of existance?

You seem to be aware of all this 'paper rhetoric', what is the reality?

You also know I ask this with respect to you as mate and a knowledgeable source of the latest ecological information

Axe

Axe,

I'm surprised at you !!

I'm sure you will get other responses especially from Filthy.

I suppose the actual impact of the lose of the native crayfish will be minimal at the ecosystem level, but the point is of course larger than that. It is the lose of another species and the subsequent further reduction in the level of our natural biodiversity. It represents another failure by man to regognise the dramatic impact he his having on his own environment that will lead to his ulitmate demise.To me the lose of the crayfish is just as symbolic as the lose of Siberian tigers or Mountain gorillas. Sorry if that sounds dramatic, but it's the principle of the thing to me.

The native crayfish was under severe threat due to poor water quality before it was put under further pressure by the introduction of the deadly fungus (Aphanomyces astaci) Fortunately and rather ironically the native crayfish is relatively common in Ireland (although not actually native) and represents the largest reservoir of the species in Europe.

The crayfish is an important sentinal organism, rather like the otter, or stone flies etc. there presence is an important environmental indicator of the health of our native fauna.

Cy.

No need to be surprised MrYates

I think the surprising thing about my post is that they were genuine questions from someone who has never met a crayfish, ever. I've never even seen one and certainly did not know that if they were lost to Britain; would be lost to the world. The native bit was lost on me last night, as I was trolleyed.

I was just having a little fun with Filthy in the way I asked them, that is all. Nothing sinister

Although I am pleased that you were surprised at me.

Cheers

Axe

Although from what I have heard they sound absolutely delicious.

From Axe "Although from what I have heard they sound absolutely delicious."

Can't speak to your native species but the tails of the signal are wonderful. The heads are full of some really tasty goo as well but you have to be a really hard-core cray eater to like that part. I am BTW. Buy them in 50lb sacks and boil them up (like lobster - they gotta be alive) with an equal amount of potatoes and a good seafood spice.

Hard to beat on a warm evening, outside, with plenty of beer. Makes a really great party.

Axe, my thoughts are pretty much as Cy says. The cray is one of our best indicator species of pollution as it needs clean water to thrive. For example I used to chase them about in the river Blyth about 10 years ago but now I can't even find one, probably through agricultural run off (stoneloach also seem to have declined dramatically here).

I think our knowledge of the native crays is insufficient to be able to say what the consequences of losing them would be. They may perform a vital aspect to the river ecosystem that we don't know yet, for example there may be species that rely on the native cray (i don't know if there are). Hence the need to protect them in the first place. What right have we to cause a species to go extinct that has evolved over millions of years and was doing fine until we introduced another species that not only outcompeted it physically but carried a pathogen. Also if the non natives are allowed to spread without check they may have far reaching consequences on the river biota, research is needed and being done I believe.

A good example to show the lack of knowledge and consequences of introducing alien species is the edible periwinkle (Littorina littorea). These were taken to the USA to be used as a food source by the new settlers. They were released and colonised the shore of the eastern coast well. a little too well in fact! They are now the dominant species on the rocky shores of the Eastern US as they don't have the predators and pathogens they should have. No one knows how many species have gone extinct or been drastically reduced in population size because of them.

Thanks Filthy

But at what point does a species become a pest?

From what I have understood so far is that the native crays are protected, but are also a nuisance in general, and serve no other purpose than to infiltrate our waterways with a negative effect toward those that come up against them: ie anglers.

Rats are a pest too, and appear to be fair game by all bodies concerned. Why is this? Considering that even I would not want to add garlic, corriander, basil and ginger and a hint of black pepper, to a dead rat!

Why the sacred/protection status?

Axe

PS. I would probably add sea-salt by the way, as it is more cheffy accepted than your bog standard Saxo.

FA - When you say "The cray is one of our best indicator species of pollution as it needs clean water to thrive." do you hopefully mean unpolluted rather than clean?

Not sure about the UK species but ours are also known as mud bugs and just love muddy puddles as well as rocky clear streams. In fact, some of them build a nest hole in the mud near, but not in, the stream.

And for clarification, can you take signals from the water? Otherwise it seems really odd since the effort is to protect the native species and yet it cannot compete well with the signal.

If you have a problem with crays, just give me a ticket to your lake, I reckon I could eat my way through the entire population of signals in a year or so. Mmmm BBQ

Brrrrppp

Axe,

I don't know anywhere where natives are a problem for anglers, only signals and turkish. They (natives) are not common in lakes, there preferred habitat is typically chalk streams or at least areas with a high dissolved calicium content.

Your point about at what level does a species become a pest is a tricky one and will depend on ones perspective. The trouble is that like it or not that in this country we live in a largely man impacted environment where any "balance of nature" has long been lost. there are few, if any pristine habitats, left. The result is that we have to constantly manage our environment to maintain any sense of "balance". For example if we take the crayfish's preferred habitat, somewhere like the river Test or Itchen, these rivers are heavily managed for game fishing e.g. stocking of salmonids, removal of cyprinds, removal of excess weed (normally in excess because of the over use of artifical fertilisers), cleaning of redds because of low flows caused by excess abstraction, coppicing of willows and alders the list goes on. On the other hand many mature gravel pits (an entirely man made habitat) have ironicaly become SSSI's. Even the Norfolk broads were originally created by the digging of peat. Deer can be a pest if numbers are not managed and racing pigeon owners hate perigrine falcons and some game keepers have (perceived) problems with buzzards. At one time salmon were so common in the Thames that there were restrricitons on how many times a week you could feed it to servants, similarly with native oysters in Essex.

We are in a vicious cycle of management, take a look at your back garden and what happens to that if you leave it fallow for a couple of years.

No easy answers I'm afraid.

I'm all for reintroducing some of our "native" species like beavers, wolves and bears. It might not sort out many problems, but it would be fun !!

Cy.

Axe,
Pretty much as Cy said on the pest front and I have never come across a water where the white clawed cray is a 'problem' although the anglers at Brasside seem to think they are for some reason (reading too many comics probably). When i fished it they weren't a nuisance at all and just wandered around in the margins at night.

About 5 miles from me is a power station which has been used as a nest site by peregrines for the last 6 years. However there are pigeon lofts nearby so the pigeon racers don't like them and want them killed, even though they mainly feed on the skemmies and wood pigeons around Blyth. Are these a pest then? I would say no because they are only returning to areas they formerly occupied before they were almost driven to extinction by man. we have also provided them with a suitable habitat in the form of an artificial cliff (the building) and plenty of feral and woodpigeons because of the waste we produce.

Slightly different are grouse and hen harriers. Game keepers would regard hen harriers as a pest because they eat grouse, which is only their natural diet in the first place. The almost went extinct and are returning to moors. Game keepers will want to exterminate them if the reappear on 'their moor'. What the hell do they expect if they are managing a habitat that is the habitat favoured by the secuies in the first place? Instead of thinking 'oh no they'll cost me a few grand in grouse' they should be thinking 'blolody hell we have hen harriers back so we must be doing it right to support a population of them'. Besides there will only be as many hen harriers as the grouse population can support, therefore if you remove grouse by shooting you will only have a small population of hen harriers, which live at a low population density in the first place.

Things like rats and rabbits are a pest as they aren't native to Britain. Rabbits can decimate habitats if left to run wild and are out of hand, however they do provide some uses on habitats like sand dunes where they help to maintain the vegetation type through their grazing (a complex thing that i won't drone on about for ages like I have above )

Newt,
Yes I mean pollution free. Everywhere I have encountered the white clawed cray has been clear though.

As far as i know you can remove signals under licence/permission and you need this to try and prevent translocation into other waterbodies. The whole signal situation is being looked at at the moment by the EA and EN/JNCC.

Nice piece FA. Good information.

If your whites only like clear water, they are for sure a bit different than the US varieties you folks are having problems with. "Mudbugs" is a fitting name for them.

One tiny quibble. You wrote " ... Rabbits can decimate habitats ... " Since decimate means to kill/destroy 1/10, I'm not sure that is the term you intended there.

Newt, decimate as in destroy, through their digging and grazing. Have a look for some picuters of what they have done in Australia for the best example of how destructive they can be.
They are becoming a big problem in my local country Park as they are preventing the natural woodland flora from growing through digging (burrows and to get roots) and grazing seedlings and new coppice shoots.

With rabbits the solution is fairly simple. They are tasty and if hunted, the population will stay at a nice low, tolerable level. Also if the pred population is reasonable, they will stay under control. Foxes and hawks - to name just a couple - are very fond of rabbit and very good at catching them.

I've seen some of the OZ things. OTOH, they don't allow guns over there at all so IMHO they have asked for part of their problem. And I seem to remember they totally lack any pred that will take a rabbit other than the occasional croc if the rabbit is stupid enough to get too near the water. Bad situation altogether and I'm not really sure how (or if) they are going to get it under control.