Signal Crayfish Extermination?

[Steve Burke]

Liam (and a few others), could you please leave a line between your paragraphs. My old eyes find your posts hard to read, and I suspect others feel the same. If I'm tired I often don't bother - which I'm sure you don't want!

 

Thanks.

 

[ 16. May 2005, 09:39 AM: Message edited by: Steve Burke ]

[argyll]

From my dealings with the EA, it appears that the whole issue has been shrouded in mystery and as usual, like the Close Season, legislation applied where and when some desk jockey feels its appropriate.

For some time crayfish have been extracted by anglers and other individuals from various small rivers and canals without the apparent need for a licence, whereas the rules for other waterways like the Thames are completely different.

I was actually told that crayfish pots would be a hazard to boats on the Thames as though they wouldnt be a hazard on the various canals and rivers where trapping happens on a regular basis.

I'm told its about protecting native crayfish. WHAT NATIVE CRAYFISH ? If others are reporting their disappearance from the Kennet, then for sure they are not in the Thames.

Why cant the EA establish where there are definite viable populations of native crayfish, ban trapping on those waters and put all of their efforts into irradicating signals on those waters. ie where it makes sense.

Then treat crayfish like any other fish. ie allow certain quantities to be taken for the table, or whole populations in private lakes an rivers to be taken out under licence.

 

[ 16. May 2005, 03:13 PM: Message edited by: argyll ]

[trent.barbeler]

Dear Gerry,

 

You said,

 

"Why can’t the EA establish where there are definite viable populations of native crayfish, ban trapping on those waters and put all of their efforts into eradicating signals on those waters. ie where it makes sense."

 

Definite viable populations of native crayfish are already established and well documented Gerry as a great deal of these recognised colonies fall within SSSI sites. My local river holds such colonies. And where these known colonies exist, it’s noticeable that their dwells "NO" signal crayfish. That’s why the native species thrives so much in these areas and why EN and the EA are desperate to keep signals out of these areas because they are quite simply, the last bastion and shred of hope our native crayfish have.

 

Leon,

 

There is quite an array of research that has been undertaken regarding signal versus white clawed crayfish. And the bulk of this research is used by government agencies in dealing with the problem.

 

It’s my opinion that given the present technology available, the best we can hope for in terms of protecting our own native crayfish against alien signal invasion, is to stringently preserve our known colonies of white claws. Obviously, DEFRA and all of the agencies in association with it feel that the trapping of signals is best left to the experts.

 

Signals and white claws don't co-exist for long together so where there are vast numbers of established signal crayfish, such as the Upper Great Ouse around Buckingham for instance, it’s almost 100% certain that native crayfish don't exist there any longer.

 

Liam,

 

A two pound chub is easily capable of dealing with a full grown signal crayfish as are many other fish species. Herons and other fish eating birds are fond of them as are otters and mink.

 

However, there has been some talk of alien species being able to find a natural balance once introduced into foreign environments. This is not the case with signal crayfish as our own native species is unable to thrive alongside them. What’s clearly highlighted here is the need for tighter controls concerning alien species and how they get introduced and how they effect already established native species. Environmentally, we hear too much talk too often and not enough action with too little money being allocated to areas of real environmental conflict that effect us all in the end.

 

The clock is ticking for our native crayfish. And as you know Liam, this issue remains just one amongst many on our rivers that cry out for more input from successive governments who should be putting "OUR" money where "their" mouths are concerning conservation.

 

Regards,

 

Lee.

[ricey]

are there any images of signal crays etc?

i've never actually seen one, so i want to know what to look out for if i do see one. wouldnt want to accidentaly kill one of the endangered ones!

[Brian Carragher]

Click on the EA website and then on the links to signal crays and you will see a picture of one

You can't mistake them ,as the name suggests they have a bright red flash down both sides of the head and on both claws.

The English variety the white clawed cray is a brownish colour on the upper part of its shell and a creamy white colour on its underneath.

There is also a big difference in size with the signal being the larger of the two and can grow to a size comparable to a small lobster.

The first signal you see you will easily identify due to the red claws and carapace (head) and if you do catch one it is illegal to return it to the water,crazy when the EA does'nt allow trapping of signals and their removal from the water but insists on non return of said species if caught on rod and line

[Clax_Clax]

i dont care what they look like they are bloody annoying

[ayjay]

ricey:

are there any images of signal crays etc?

You could always use http://www.google.co.uk , just go to *google*, select *images* and type in *signal crayfish* or anything else you want pics of.

[Liamsm]

Hi Lee,

I can’t find anything to disagree with in the part of your post to me.

I think that we are mostly in agreement about what should be being done. And! who should be doing it.

My view was more a supplement to it all really, in getting every river angler involved, or rather giving the opportunity for it.

 

As for the research that is being done on the effects of signals on our unique environment!.

There can not possibly be any conclusion to such research, without speculation, or projection.

As the end result, or full consequences of this invasion by the signals can not be seen on any of our rivers yet.

 

As we have both concluded and stated, a natural balance with the signal crayfish in place within our eco system, can not happen without changing it completely. There will be a natural balance one day, as nature dictates it, but by then our rivers will be a lot different than they are now.

 

I am mindful in this discussion that I live on the Kennet which is a lot further along in the progression of the invasion (probably more than anywhere else) than the waters where you are. I have seen the Kennet which is not a big river, change dramatically over the last thirty years and the signals are only one of the problems.

 

Some of the points of views being put forward, from those living in areas where the native crayfish still survive and rivers that are not totally infested yet are things that were thought about and tried many years ago on the Kennet. They have not helped much to date though , but are not being changed.

If there is not a change of ideas, I can not see how these other rivers can avoid the same fate.

 

“A two pound chub is easily capable of dealing with a full grown signal crayfish as are many other fish species. Herons and other fish eating birds are fond of them as are otters and mink.”

 

I am completely aware of all this Lee, I was trying to draw attention to the fact that most people overlook that a very large portion of the smaller ones are eaten by fish of all sizes and all species in even greater numbers. Therefore excluding it from the same scenario that we had with pike culling.

 

Most people do not know what an immature crayfish looks like and even tend to exclude them from the equation, when thinking about the problems, or views within a debate.

 

It has to be said that one of the most contributing factors in the survival of the signals on the Kennet, (that is very well fished), must be the introduction of the large amounts of anglers bait that is often used.

 

If this bait was absent, it would have a two fold effect.

No extra food for the crayfish to feed on,( does an abundance of food lead to greater propagation in nature?) and no food for the fish, forcing them to feed more on the crayfish.

The negative side might be that the Signals may feed more on the fish eggs, if deprived of the anglers bait. How this would all balance out is hard to say.

 

I definitely would not rule out the part that anglers play in the balance of our eco system on a river like the Kennet though, as I would not rule out the effect of the most seemingly insignificant inhabitant of our rivers, or the way that we treat them.

 

………….Liam

 

[ 18. May 2005, 04:24 PM: Message edited by: Liamsm ]

[Clax_Clax]

i think that they should alllow people who catch them when fishing etc, shoud be able to kill them, eat them or do whatever thwey want with them as they are a pest and shouldn't be in some waters,