<< These estuarine crabs can live through all sorts of environmental
variations. The limiting factor is that they couldn't successfully reproduce
in total freshwater. >>
Yeah, I'm not surprised by that; it seems like that's the case for any
organisms that are mainly salt water but which also enter brackish and fresh
water. The conditions are not right for them to spawn in freshwater, but many
organisms from the ocean seem to be opportunists that take advantage of
favorable living conditions to migrate into brackish and freshwater areas to
exploit the resources- everything from crabs to bull sharks. I would like to
add that I was told that my fiddler crab came from Florida, and that a pet
store owner told me that fiddler crabs were supposed to be found in rivers
that led to the ocean, but come to think of it, it was probably in another
low-salinity area of the river rather than true freshwater.My crab has
successfully molted a couple of times; the well water that I keep it in has a
high mineral content and smells faintly like sulfur a lot of the time. It
even tastes a little salty, so maybe it is technically low (extremely low)
salinity.
<< These crabs are tough, no doubt about that! >>
I second that! I saw a program about thermal vents at the bottom of the ocean
floor and they were talking about this crab that they had brought up the
surface without taking any special precautions to depressurize it or
whatever you call it, and the crab survived it. He survived going through all
of the pressure changes from the ocean bottom to the ocean surface 6 times if
I remember correctly. Crabs seem to be pretty tough all around!
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