native blue crawdads?

hi, i found some absolutely gorgeous blue crawdads in the Guadeloupe creek (san jose, california, 95112). up until now i have never seen any crayfish here other than an abundance of louisiana red crawdads. several months ago i went creek walking and scooped up a bunch of baby crawdads. they were extremely tiny, so i brought them home and dumped them in a big tank full of driftwood that i was curing. the water is basically coffee colored and has been for a while, but they have grown and thrived and the other day i noticed that they had been developing a sort of blueish tint. i thought that was pretty so i pulled one out to take a picture.

he looks like exactly like an electric blue crayfish; deep deep blue color and similar body proportions. unfortunately i also discovered that my camera is quite broken. i will take some pictures as soon as i can find another camera to use, and post them here.
does anyone here have any tips for breeding these guys? i figure since theyre not californian natives i might as well take advantage of my good luck and fill my sixty gallon with blue crays. might even be able to sell the youngsters. also, is this a mutation or a species? one or two of them just look brown, and i am not sure if i should take them out before breeding.

thanks

I once saw a crawfish here in Central KY that was blue. I thought maybe somebody release on of those electric blue crawdads from the pet store. I havn't seen one since so I'm betting that was the case. doesn't really help you, but I thought I'd share.

I once saw a crawfish here in Central KY that was blue. I thought maybe somebody release on of those electric blue crawdads from the pet store. I havn't seen one since so I'm betting that was the case. doesn't really help you, but I thought I'd share.

cool. i think its pretty funny that you can just find these guys in the US. i just recently sold one to a customer in the local fish store i work at for nearly 30 bucks.

Oh, and they seem to be more peaceful than the red crayfish i used to catch. i have a pretty big variance in size and even though they make a big fuss when they face off with each other, their numbers appear to be pretty stable.

Edited by brynneth, 21 December 2009 - 04:16 PM.

we find a blue colored crawdad here in Ohio
most often in the tribs of the Little Miami River.
SKIPJACK said they were native and it is
just a color phase.

The blue mutation shows up periodically in plenty of crayfish species. The commercial "blue lobsters" are usually blue morphs of the common Florida crayfish, Procambarus alleni. Blue morphs of the red swamp cray (P. clarkii) are also around in the trade. If that's the main crayfish found in your creek, that's probably what your blues are as well. Do they have the white knobs on the claws like typical P. clarkii?

The blue mutation shows up periodically in plenty of crayfish species. The commercial "blue lobsters" are usually blue morphs of the common Florida crayfish, Procambarus alleni. Blue morphs of the red swamp cray (P. clarkii) are also around in the trade. If that's the main crayfish found in your creek, that's probably what your blues are as well. Do they have the white knobs on the claws like typical P. clarkii?

i did not notice white knobs on the one i was looking at, but i already dumped it back in the tank. i will pull it out again in a few hours and also will find my boyfriends camera to get some pictures. i did notice that the non-colored youngsters did not particularly look like your average clarkii babies when i caught them, and like i said, they are much more peaceful than i am used to. i am leaning towards something other than clarkii but not sure yet. pictures to come as soon as possible.
they are not as brightly colored as the blue crays i see in the pictures online, but i suspect that has more to do with selective breeding than species.

Eagerly awaiting photos.

I caught some of what were likely native crayfish in the shallow of Lake Tahoe and they varied from rusty brown, yellow and black, orange, and blue. Interesting stuff. Of course, any we tried taking home died rapidly in transit.

Adult crayfish are best transported with only a shallow layer of water in the bottom of the bucket, maybe a quarter inch or less. They are very demanding of oxygen and will often asphyxiate in the stagnant water of a bucket. They are quite capable of breathing air though, so if you give them just enough water to keep their gills moist without submerging them I've found they travel well even in hot weather.

Adult crayfish are best transported with only a shallow layer of water in the bottom of the bucket, maybe a quarter inch or less. They are very demanding of oxygen and will often asphyxiate in the stagnant water of a bucket. They are quite capable of breathing air though, so if you give them just enough water to keep their gills moist without submerging them I've found they travel well even in hot weather.

Does this apply even to crayfish taken from cold mountain streams? I did catch 2 signal crayfish a few years ago and they traveled well in a manner similar to that which you describe.

I would expect that if they came from a cold mountain stream they would be even more accustomed to high oxygen. I have certainly found crayfish in warmwater swamps where oxygen is low, but they tend to be much smaller in that environment and live in shallower water. I haven't transported any from the kind of streams you're talking about, but I would think the same principle applies.

As someone who has been researching and keeping large numbers of crayfish for over three years, I have learned that crayfish have a strong tendency to turn blue when exposed to aquarium lights. There are also genetic blue crayfish, which will turn a more intense blue when maintained in these same conditions. The big question for me is how to keep them from turning blue. They won't when the light is shielded by a dense mat of duckweed at least. I'm experimenting with aquariums without lights, but the results aren't in yet.

As someone who has been researching and keeping large numbers of crayfish for over three years, I have learned that crayfish have a strong tendency to turn blue when exposed to aquarium lights. There are also genetic blue crayfish, which will turn a more intense blue when maintained in these same conditions. The big question for me is how to keep them from turning blue. They won't when the light is shielded by a dense mat of duckweed at least. I'm experimenting with aquariums without lights, but the results aren't in yet.

That's a pretty interesting observation, and I haven't heard of that before. I've seen crayfish get a bit more blue/green coloration after being held in an aquarium for a while (especially post-molt, I think), but I attributed it more to being transferred from ponds/lakes with a muddy bottom to clear water with gravel bottom.

Do you have the same type of light on all tanks, or a variety? I'm curious how blue you're talking -- photos?

The blue color is the result of a mutation where exoskeleton pigments are lacking and the blue color of the oxygen carrying proteins in many crustaceans (called hemocyanin - some still have hemoglobin) is visible through the exoskeleton. The blueness is variable with the amount of exoskeleton pigments, so that a partially pigmentless animal will look slightly blue, the completely pigmentless will be SCREAMING blue.

This can happen in many species, but is a rare condition in the wild, perhaps due to crazy blue individuals getting eaten preferentially due to their obviousness to predators.

If you search on "blue marmokrebs" on the Forum, you'll find some posts from the past where we were talking about this, and the implications of a parthenogenic species being able to have this mutation (I still can't fully get my mind around that). There should be a picture there as well.

Todd

Neat! But why shouldn't a parthenogenetic animal be as prone to mutation as a sexually reproducing one? Obviously two mutations in the same lineage would be required if the trait is recessive, but "failure to produce pigment" mutations seem to be very common. Who knows, maybe all marmorkrebs carry such an allele and only require a single further mutation to become blue.

That's what we were guessing. It's a deletion, rather than a homozygous recessive trait (I said this wrongly in my first post) in Marmokrebs. Yeah it is neat stuff

Todd

Edited by farmertodd, 09 March 2010 - 03:16 PM.

my mom works at a waste water treatment plant and right at the outflow into th blackstone river there used to be 1000's of crayfish there and 25% were blue. and they were 4" plus. they were huge.....and now there are no crayfish but 1000's of suckers there now.

I ran across this photo while cleaning up today. I don't think I ever post a picture of a blue marmokrebs to the Forum now that I followed my own search suggestion

 Blue_Marmokrebs_sm.jpg   140.17KB   1 downloads

Unfortunately, they all died when an air pump burned up. Boy, did that stink (in multiple ways).

Todd

Todd, i kinda doubt whether the blue color in crayfish is simply hemocyanin in the blood showing through a weakly pigmented exoskeleton. The shed skins of blue P.alleni are blue, and I doubt there would be that much blood in a shed. Just guessing here but I think there's a pigment involved, either a structural pigment or something like the "true blue" in darters.

The blue color is the result of a mutation where exoskeleton pigments are lacking and the blue color of the oxygen carrying proteins in many crustaceans (called hemocyanin - some still have hemoglobin) is visible through the exoskeleton. The blueness is variable with the amount of exoskeleton pigments, so that a partially pigmentless animal will look slightly blue, the completely pigmentless will be SCREAMING blue. Todd

If I remember correctly from a long, long time ago when playing with horseshoe blood in physiology lab, when oxygenated it wasn't quite that blue. A nifty blue, yes, but more of a cool-aid color than a day-glo color. But I may not be remembering it correctly.

You guys are probably right. I was going on what a prawn aquaculturist told me. Based on Gerald's observation about procamburus molts, I can totally get behind that.

Todd