Aussie salt water myth?

[Guest]

Thanks for the info Sugar, but still not the issue at hand can we please stay on topic.

I know it was all of us that wondered off the real topic but lets get back on it. Because no matter where they are from in Aus. they can take little walk down to the beach, and I am sure they do.

[suebee]

i never said anyone was lying as posted above. This paper is for more then just one species of crab.
Other then poking at me lets add things to the thread that help it along and not get this thread closed before its does more harm then good. I think from the added information above that more then i would agree the salt water restriction is NOT a MYTH. Im so glad that was pointed out before it could do harm to others crabs.

[wodesorel]

I think we are getting off topic a bit, the issue is should they have constant salt water or not correct? I find where they are collected from and the other information very interesting but lets try to answer the first question.

But having constant access to the ocean IS part of the topic.

If they can just walk down to the beach and get a drink and they aren't dying off in nature, then why would it be a problem to let them have a bowl of salt water while in captivity.

And more than that, if they're from inter-tidal areas (ie, constant salt water) then wouldn't it be doing them harm to strictly control when they can and cannot drink it? They seem to have developed to live in area where it's a necessity!

The goal to have healthy hermits is to replicate as much of their natural environment as possible. Aussie crabs live on the beach, and so therefore should require salt water.

[sugarselections]

Izzysmom you have provided some great links, that first one is really good it tells us the reasoning and that it can dehydrate them if they drink it.

That information is actually taken directly from the Crazy Crabs website. That's the same website the recommends gravel and wood shavings as proper substrate.

[Guest]

Okay, let's do examine the documentation:

On one hand... we have the guidelines from the vendor in question, who has cared for the "crazy crabs" (even copyrighting the name) since 1979 and states in no uncertain terms after caring for thousands of these animals for 3 decades that too much salt water will dehydrate them. This is agreed with by various wildlife agencies and pet associations in Australia, who all naturally have better access to these crabs than we do. All stress moderation of salt water intake.

On the other hand, we have an application by a single vendor mentioning, quite vaguely, the harvest area. With all due respect, to draw any environmental care guidelines from these couple of paragraphs is simply wild and unfounded conjecture. And to state the effects on a few crabs while ignoring over 30 years of data on countless thousands of the animals is kind of wreckless.

[Guest]

Here's a couple more quotes worth pulling from that site (with emphasis added): http://www.petalia.com.au/Templates/Sto ... =1381#ct-8

In Australia, land hermit crabs are usually found along beaches and around mangrove swamps in the tropical northern regions. Land hermit crabs live in large colonies and move between the sand dunes and the high tide mark at different times throughout the day. Hermit crabs are nocturnal. During the daylight hours, they spend most of their time snoozing amongst low growing vegetation or buried in the sand. At night, they venture out to the beach searching for food, bathing and exploring new shells to move into.
In Australia, land hermit crabs hibernate inland from the coast underground, between late April and late August, the winter months.

Stage 2 - Terrestrial Stage: The crabs move onto the land after growing to around 5mm where they move into their first sea shell home. At this stage of life, their gills change slightly and must be kept moist to allow oxygen to be extracted from the air. Humidity is important for both keeping their gills moist, and for extracting moisture for drinking. This is why the crabs venture down to the waterline at night to breathe the humid air contained in dew that falls on the beach.

I don't know, I understand being on the safe side, but, if the crabs do just fine in nature deciding what they can and can't drink, why wouldn't they be able to do that in the tank?

[Guest]

Again, this is what science calls wild conjecture. You are basing assumptions on the most superficial descriptions of habitat and behavior. Bringing this to the table against decades of first hand information on thousands upon thousands of what qualify as case observations in no way even begins to crack the foundation of established needs in captivity. In fact, information from early trials by vendors of these crabs indicates fairly clearly that continuous availability of salt water can be disastrous in captivity.

The bottom line is if you think this superficial information trumps the concrete and proven information on the care for these wee cuties, then more power to you. I hope you get lucky like Sugar did. I think if the Aussies have been having luck getting them viable enough to export with these methods, I'll stick with what has worked for the past 30 years.

[wodesorel]

In fact, information from early trials by vendors of these crabs indicates fairly clearly that continuous availability of salt water can be disastrous in captivity.

Where are you getting this information from?

I would question any information given by a large-scale hermit crab distributer. After all, look at all the misinformation that is given about PPs! The beach-front sellers (like Shell Shanty Inc.) have been selling them for 30 years here in the states. Does that mean we should blindly trust them when they say they can live on gravel in a wire cage and painted shells are healthy? Just because someone has been in a pet business that long does not mean they have all the answers. I think that has been proven time and again when it comes to PP care.

[Guest]

I was just asking a question GCInin. Please don't get so upset. I don't even have Aussies, I was just trying to help...

[Guest]

I've listed a couple of scientific papers below. Unfortunately, there's somewhat of a lack of research to indigenous coastal life in Australia, particularly among terrestrial hermit crabs and crustaceans.

While it has been mentioned by posters here that like other crabs, they live near to and have ties to the ocean. What has not been mentioned is that quite unlike other terrestrial crabs, the variabilis has a substantially abbreviated salt water phase - venturing onto the beach and burying well before developing out of the larval stage. Also, when it comes to water, the majority of their time is spent in fresh water. While they do venture onto the beach for moisture, food and shells, actually venturing into the salt water like other crabs is relatively rare except for laying eggs. Everything in the life cycle and environment of these crabs points to limited salt intake when compared to other crabs. That, combined with environmental conditions, temperature and humidity, also indicate more potential for the salt content to induce a risk of dehydration. Again I say: your conclusions are based on the most superficial of information.

Regardless of whatever government investigations, scientific data or owner verification in Australia might back up the information, ultimately the people with the most experience with these creatures, the most qualified to offer observations and data, and the public originators of these care guidelines are indeed the vendors, and ultimately it seems you are not going to accept information from them. Consequently, any evidence I offer will be summarily dismissed, so there's really no point to any further discussion. It's a shame that the practices of unscrupulous vendors like PetSmart in the west have lead to an unreasonable distrust of the rest of the world. And again, good luck to you and your crabs. I see no basis for reinventing the care book for this species, and my crabs are thriving (as must be most of the ones in Australia).

A field guide to Crustaceans of Australian Waters"
D.S. Jones
The Australian Journal of Crustacean Biology 1992 edition

[Guest]

Izzysmom,
I am not upset, just trying to provide good information.

[kgbenson]

What is the concentration of salt in variabilis shell water when the animals are studied in the wild? Say compared to other coenobita?

Keith

[Guest]

Keith, I am having trouble finding that still looking .
I did find that the wet and dry seasons of the areas the variabilis is native to make for drastic differences in salinity of the sea water. This can range from typical 32-35 PSU in the dry season to as low as 6 psu in the rainy season. Few animals of this type can withstand such drastic changes in salinity, which is further evidence that the typical habitat of the variabilis is inland freshwater with less excursion into salt water than other crabs. I have found information that says of course the females access the ocean for releasing eggs, and that they do gather there likely for the humidity, but it seems the salinity of the ocean in this area is not constant.

Here are my sources for this information:
http://museumvictoria.com.au/pages/4017 ... enaway.pdf
http://www.statemaster.com/encyclopedia ... ermit-Crab
http://www.onlinegeographer.com/king/derbim.html

[kgbenson]

Shell Water Prefered Shell/drinking Water
mOsm/kg
brevimanus 835 FW
perlatus 1013-1316 NSW
clypeatus 938-970 FW


This is a quick bit of the info I have (I can't post the rest until I figure out how to format it. Brevimanus being very terrestrial and Perlatus being quite less so and you can see it in the numbers. So the question is, where do variabilis reside?

Another interesting tidbit about salt requirements. THis time in clypeatus.

C. clypeatus
Osm of Water Survival Days
FW 248
105 253
527 326
1054 174

Hmmmm - so some crabs will do less well on saline if for some reason they take in in excess. There can be many reasons why an animal will behave in a manner other than expected. Sometimes when we give animals choices, they are do not appear to be the same to the critters. Appetites and drives are developed over time in a population to fit they environs in which they reside. Change that and animals, like people can make inappropriate choices.

Keith

[Guest]

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!!
You mentioned that they sometimes make unexpected choices ones that may not be good for them. I think of that in layman's terms of alcohol for us, a bit silly but it makes the point. It is readily available to us and if we are not careful it can make us very sick and eventually cause death. We often make choices that are contrary to what is best health wise, even-though we know better.

Did you find that the different species have different salinity detection thresholds? I would have to go look it up but many are far more sensitive than I knew.

I love really breaking it down to the raw info!