Claw of Signal Crayfish - New World Invader

Bruce Williams · Post by **Bruce Williams** » Sat Jun 23, 2007 12:27 pm

Hi Folks,

Picked up this Signal Crayfish (Pacifastacus leniusculus (Dana)) claw while walking along bank of River Ouse in Stony Stratford, Buckinghamshire (England). This North American species escaped from crayfish farms into the great Ouse and have now become a serious threat to the indigenous white-clawed crayfish.

They are a particular problem to coarse fishermen as they take bottom-fished bait from the hook and generally make fishing very difficult. This claw was from a pile of badly mutilated (and very smelly) crayfish - obviously the revenge killing of a frustrated angler.

This is the first pic with my new Nikon D80 and 105mm Macro lens. Stacked 5 frames using CombineZM. Other side of claw is grey/green but smells too much to take any more pics.

Claw measured ~35mm not including "arm".

Bruce

PhilH · Post by **PhilH** » Sat Jun 23, 2007 12:34 pm

Lovely shots Bruce and good choice of background, it compliments the claw a treat

beetleman · Post by **beetleman** » Sat Jun 23, 2007 12:42 pm

A very nice stack Bruce. Excellent detail. You have to do what we do here in the USA with these little critters...."Eat Them". They even have them in the local Chinese buffet

puzzledpaul · Post by **puzzledpaul** » Sat Jun 23, 2007 1:51 pm

Splendid start with the new kit, Bruce

Is it difficult using a SLR with a face mask ... I've never tried ...

pp

Ken Ramos · Post by **Ken Ramos** » Sat Jun 23, 2007 6:19 pm

I agree with Doug, they are much better steamed and served with a little tabasco sauce!

Mike B in OKlahoma · Post by **Mike B in OKlahoma** » Sun Jun 24, 2007 7:28 am

Great start, hope you are enjoying using the new kit!

Planapo · Post by **Planapo** » Sun Jun 24, 2007 8:04 am

Bruce, these are brilliant, even literally brilliant, I mean crystal-clear.

Reminds me of good food photography and I would have liked to order butter, baguette and a glass of Riesling, if you just had not mentioned this smell.

Cheers,
Betty

DaveW · Post by **DaveW** » Sun Jun 24, 2007 11:00 am

These are the ones that were mentioned on the BBC this morning as the red clawed species that has decimated our native white clawed variety due to being the carrier of a fungus (Aphanomyces astaci) that does not seem to affect them but is lethal to our native species:-

http://www.carterecological.co.uk/crayfish.html

DaveW

rjlittlefield · Post by **rjlittlefield** » Sun Jun 24, 2007 11:17 am

Bruce, these are great! Beautiful colors, well lighted, sharp as tacks (lots of them!) and pleasantly composed.

The only negative I see is that the specular reflections are a bit of an awkward size -- big enough to be noticeable but small and therefore bright enough to be blown out. Perhaps a larger diffuser next time?

What really attracts my attention, though, is a detail of the specimen. It seems that there are little stellate clumps of fibers, especially near the ends of the claws. Do you happen to have read what those are about?

--Rik

Walter Piorkowski · Post by **Walter Piorkowski** » Sun Jun 24, 2007 11:39 am

Very interesting shots. Never would have expected such beauty in discarded refuse. I took notice of the transparent nature of the flesh near the joint in the upper image. Was the surface really transparent?
Walt

Bruce Williams · Post by **Bruce Williams** » Sun Jun 24, 2007 12:16 pm

Thanks to everyone for their helpful and encouraging comments.

Doug and Ken - Yes I like to eat 'em too. However, seems that's how the whole problem started in the UK (so I understand). Some folks thought that farming the Signal Crayfish was a good commercial proposition but as is so often the case (mink for example) they escape into the wild and mess up the ecological balance.

Paul, Betty and Walter - The smell was truly appalling (completely disproportionate to the size of the claw) so unfortunately I had to remove the claw to the bin as soon as pics were taken (so can't give good answer to your question Walt).

Rik - Yes I noticed the clumps of fibre. I havent read anything about their function but had assumed that they operated like whiskers to provide some sensual feedback to the crayfish. I'll see what I can find out.

Bruce

Bruce Williams · Post by **Bruce Williams** » Sun Jun 24, 2007 12:43 pm

Dave - Thanks for the interesting crayfish link and the pm.

Bruce

beetleman · Post by **beetleman** » Sun Jun 24, 2007 1:05 pm

"Please save us from ourselves"

puzzledpaul · Post by **puzzledpaul** » Sun Jun 24, 2007 2:09 pm

<< The smell was truly appalling (completely disproportionate to the size of the claw) >>

Reminds me of a (supposedly true) tale told on a prog some yrs ago about how jilted partners 'got their own back' ...

Guy ended relationship with gf
Gf still had keys for their new flat and let herself in when xbf was out
Took end bung out of curtain rail tubing, inserted some sort of shellfish scraps into tube, replaced bung and left.

Think there was a radiator under window, btw.

pp

twebster · Post by **twebster** » Sun Jun 24, 2007 3:04 pm

Here's an old forensic photographer's trick you can use when photographing smelly subjects. Get a few of the cheap, paper medical masks sold in drugstores to prevent airborne spread of diseases. Also, buy some oil of wintergreen or oil of spearmint. Your neighborhood drug store should have that, too. Wear the mask and put a few drops of oil of wintergreen/spearmint on the mask. I used to photograph humans that smelled worse than dead crayfish

and this trick works a treat.