Aussie salt water myth?

kgbenson · Post by **kgbenson** » Mon May 03, 2010 10:42 am

gclnin wrote:Exactly Keith,
And thanks for the info that is very enlightening. Wow at the Perlatus numbers... I think I will up that tank's salt!!

Just remember that normal salt water is: 1054.

If you start too high them normal evaporative loss might drive them too high and they may not keep up.

Pick up the book Biology of the land hermit crabs. Much of the above is in there and more. I cannot seem to find my copy . . . . . Hmmmmmm

Anyone out there measuring shell water concentration?

Keith

Guest · Post by **Guest** » Mon May 03, 2010 10:55 am

That is true.
I will get that book for sure! Thanks for the recommend.

I still have not found any shell concentration numbers.

Guest · Post by **Guest** » Mon May 03, 2010 10:56 am

Keith...how do you measure shell water concentration???

suebee · Post by **suebee** » Mon May 03, 2010 11:03 am

like a great book but a bit pricey for me right now http://www.amazon.com/Biology-Land-Crab ... 0521306906 is that the right one Keith?

kgbenson · Post by **kgbenson** » Mon May 03, 2010 2:47 pm

suebee wrote:like a great book but a bit pricey for me right now http://www.amazon.com/Biology-Land-Crab ... 0521306906 is that the right one Keith?

That's it. It is an older text, but since there isn't much by way of ground breaking coenobita research, the darn thing is still fairly current.

Keith

kgbenson · Post by **kgbenson** » Mon May 03, 2010 2:49 pm

funwithcrabs2010 wrote:Keith...how do you measure shell water concentration???

Refractometer would be one way, or if you are a lab person use an osmometer. I would use the same refractometer I use when I make my salt water. Just a drop'll do.

If I was dong research I might pick something a little more rigorous, but a refractometer should do nicely.

Keith

sugarselections · Post by **sugarselections** » Mon May 03, 2010 4:14 pm

This is all really interesting information.

The reason I started this thread was to share my own personal experience that an Aussie crab can be healthy with unlimited access to salt water in captivity. I think it's important to this site that many different viewpoints are heard. I never tried to advocate Aussie owners to follow my care practices, but I have proven that not every Aussie crab will gorge itself on salt water if given the chance.

Guest · Post by **Guest** » Mon May 03, 2010 4:33 pm

I have a refractometer. . .don't trust those plastic things.

I've only got PP's as far as crabs go. They do have access to saltwater but I've never seen them touch it. I could measure the salinity when I get home from work on one if it would be of any help.

suebee · Post by **suebee** » Mon May 03, 2010 4:45 pm

Sugar im sorry but it will take more time to tell. I dont think the period of time has proved this. How long has it been with the crab having total access to the salt water? I know you said he was alone for a while before you put him in the tank and I dont think you have had him for a year yet. I would hate for a new person to read your first posts and decide it was ok to give salt water constantly. I would call your thread a test that you are doing. One that i wouldnt take the chance of with so much information out there saying differently. I chose to go with the safest rout i can with my crabs and leave the testing to people doing the research, I get to attached to do other wise. I hope the best for your crab and you. Im also looking to protect new crabbers from reading this and thinking that its been long tested and proved that the Aussie crabs are safe with constant access to salt water.
Blessings, Suebee

Your first line in this thread states that its a myth. A myth would not have so much information to prove it otherwise. You may be doing well with your one crab, but its already been proven that this is not a myth.

aquav · Post by **aquav** » Mon May 03, 2010 5:02 pm

Just measured the specific gravity of perlatus and clypeatus shell water with a refractometer, keep in mind, these measurements were just taken from one member of each species:

1.028 and 1.025 respectively.

So, there is a definite difference. I tried to also get a compressus reading, however only had one up and was not able to get any shell water. Will try later this evening if someone else comes up.

As far as those values are concerned, for comparison, saltwater aquarium specific gravity runs anywhere from 1.022 in a LFS, to keep disease in the fish to a minimum, to 1.027 for some reef tanks that contain many corals.

kgbenson · Post by **kgbenson** » Mon May 03, 2010 5:37 pm

sugarselections wrote: I have proven that not every Aussie crab will gorge itself on salt water if given the chance.

Please don't take this the wrong way, but are you not talking about an N=1?

Keith

kgbenson · Post by **kgbenson** » Mon May 03, 2010 5:43 pm

Jeremy wrote:I have a refractometer. . .don't trust those plastic things.

Hmmm - Mine is glass and plastic. It is a fairly precise instrument akin to the one's we use clinically but with a different scale suited for salt water not plasma or urine.

Just so we are on the same page I am talking about this:

http://base1.googlehosted.com/base_medi ... 58c7&hl=en

Not this:

http://base0.googlehosted.com/base_medi ... 3869&hl=en

I've only got PP's as far as crabs go. They do have access to saltwater but I've never seen them touch it. I could measure the salinity when I get home from work on one if it would be of any help.

Might be helpful, how are you going to measure it?

Keith

sugarselections · Post by **sugarselections** » Mon May 03, 2010 5:45 pm

suebee-

Actually, I have proven that given the chance not all Aussie crabs will gorge themselves on salt water. My Aussie crab does not gorge herself on salt water. Simple as that. I'm not saying that's the whole story, but it is one part of it. She has not dehrydrated and died as I was told she would if given constant access to salt water. I agree that I will have even more beneficial information on this topic in a year or so.

Guest · Post by **Guest** » Mon May 03, 2010 5:59 pm

kgbenson wrote: Hmmm - Mine is glass and plastic. It is a fairly precise instrument akin to the one's we use clinically but with a different scale suited for salt water not plasma or urine.

Just so we are on the same page I am talking about this:

http://base1.googlehosted.com/base_medi ... 58c7&hl=en

Not this:

http://base0.googlehosted.com/base_medi ... 3869&hl=en

I have a refractometer just like the first link you posted. I think it's glass and rubber and I did recently calibrate it. The plastic things I don't trust are the second link you posted. I think we're on the same page.

kgbenson wrote:Might be helpful, how are you going to measure it?

Keith

Well I'm not exactly certain being so new to crabs, but I would need to get shell water out of the shell possibly by turning one of my PP's upside down until I get a drop or two and measure it that way? Suggestions?

I thought this conversation was interesting and thought I might participate if I could.

Guest · Post by **Guest** » Mon May 03, 2010 9:07 pm

I think it is wonderful that you are trying to get us readings! I need to get some from my aussies so we can compare our numbers. Keith how should we do this, tip them in their shells a bit? I also have 8 different species we can test from... Lost my other blue the other day

or it would be nine...
When I get them will depend on how long shipping takes and such.

Sugar, we will have to wait and see how it goes for your little guy to make any kind of conclusion about that situation. What we are doing here is trying to get the best educated guess. Observation is only one part of the research, we have to have some hard number comparisons as well. What you were told is how they have been kept for a long time, unlike other vendors the 'crazy crab' people say you can have your pet for many years with the right care. so they obviously do not treat the species as disposable like many vendors in the US do.

This is a wonderful thread I think... looking forward to the replies and results!