Carapace sizes

[genecrabman]

I had a Dr. in Biology that worked for the State of NC tell me that, Potty Mouth, Thats about the only thing I might agree with.. The waters closer to the inlets are much more salty and warm,also the water has much more oxygen in it, So they harden up much quicker after each shedding process,cause a shorter harding cycle..Where as the colder,fresher water may take the crabs an extra day to harden up, thus making them max out on size each time they shed..

[Dreampixels]

Is it just possible the reason for difference is same as humans, some 5 ft 5 and others 6 ft 2?

[jack1747]

I am having a hard time buying that a hard crab can change its shell without a slough.  Guessing here but, I think they are saying after weeks of exposure to predators the crabs shell goes back to the wild crabs at the next shed….

[Dreampixels]

I am having a hard time buying that a hard crab can change its shell without a slough.  Guessing here but, I think they are saying after weeks of exposure to predators the crabs shell goes back to the wild crabs at the next shed….

I would agree with you there Jack. Pay close attention to the mature females, their spines normally appear straighter and longer the most males. Also the Lady Paints Her Finger Nails applies 95% of the time, I have caught males with a red or orange claws.

Also what they must be saying is we can actually watch evolution take place...........if the crab develops better defense once turned to the wild.

[genecrabman]

Is it just possible the reason for difference is same as humans, some 5 ft 5 and others 6 ft 2?

DOES COLD WATER DO THAT?

[Dreampixels]

YES!

[Steve]

I just realized something else about the first photo that's posted to this thread. The crab on the left exhibits swept-forward spines... that would seem to indicate that the crab burrowed into the mud immediatly after molting while its shell was still soft. Crabs burrow by backing into the mud (butt-first) which would cause its still-soft spines to bend forwards. The crab probably did that to hide until its shell hardened up.

Also, I'm now less inclined to think that it's a species thing as I had originally thought. I have in my hands the book "Shrimps, Lobsters, and Crabs of the Atlantic Coast" which details many of the crab species in our area including Callinectes bocourti, C. danne, C. exasperatus, C. larvatus, C. ornatus, C. sapidus, and C. similis. All of the other species are smaller than our beloved C. sapidus and max out at about 5-inches point-to-point. So now I'm leaning towards habitat.

[Potty Mouth]

What Jack says makes sense about not changing spine shape ubtil the slough... and yeah, I can agree with habitat, that must be the ticket in the sense that they are using each molt to become less likely to be a meal... goes along with what everyone is observing... and, good thought on the spines curving forward.  I saw that and thought about it for 1/2 a sec but, other than the fact that they looked pretty mean, I couldn't speculate as to what caused it.  That's quite possible and also winds up making them harder to eat face first... 

[tugcapt]

If a male crab is holding a soft sook, can that change the sooks shape by the way it is pressing against the shell?

[captaincrab55]

If a male crab is holding a soft sook, can that change the sooks shape by the way it is pressing against the shell?

If it presses the right spot    the Female will form a Sponge....

[genecrabman]

If it presses the right spot    the Female will form a Sponge....

OK this thread has changed to PG-17..

[jack1747]

I have had a number of soft crabs in my float with lateral spines bent.  Since they did not harden I don't know if the spines would have straighten out or not.  The bend ones were crabs that got hung up for a while backing out.

[oldsunbear]

As I read the different "scientific" descriptions of all the similar crab species it seems that those that have a smaller maximum carapace size are less tolerent of low salinity.
It will be interesting to see with this contest coming up, where the biggest crabs come from. Are they close to or in bays, rivers or bayou outlets or truely out in the higher salinity of the gulf or sea.
I am betting on the brackish water crabs.

[genecrabman]

The brackish water crabs are always bigger, but the sooks always go to salty water to lay their eggs..You hardly ever see a sponge crab in brackish waters..But.. I'm not a scientist, I've just crabbed for 40+years..

[Potty Mouth]

I agree with Gene as it's what we also observe up here too... I crab up in a brackish river most often and we see big crab here vs. my buddy who is comm. and crabs in the bays right off the ocean.  He'd have to pick through a few basket to get a doz. of our average sized crab up here and I'll deny it when you tell him I said that... (just so you know), but ummm.... And, sponge-crab there certain times is sometimes WAY more than half of everything you catch...  but I digress...  So, I think the brackish/bigger argument definitely holds up (when they are around and you can find em).  OSB's comment, makes sense too.  Could be there is a correlation on body size vs. tolerance for low salinity.  Big may make a crab more able to use the environment it's in.  Perhaps larger carapace and body can store more of the calcium and minerals crab prefer or maybe the larger body can utilize less salt and survive by using the gills to collect & store salt and minerals (larger body = more water processed/minute = larger gill = get more surface area and more mineral/nutrient?).  Scientists could test that out which would be cool for someone's doctorate or whatever.  The big boys run back out too, so, it's not like they stay here but, at the right time, I think brackish has more of the real big jimmies that are about a slough shy of a 9" crab... the big jimmies are out in front of the masses scouting for opportunity... up here, the hot dry summer pushes salinity up into the rivers and it gives em the range to access more food sources.  It's like they move up the food chain as they head up the bay and get away from the rays and rockfish down south.

[R D]

We see the same thing Gene see's down here,the futher up a river you go the longer the points on the Jimmys.