Red Rock Crab Behavior Question

Fish & Invertebrate sightings and descriptions, hosted by resident NWDC ID expert Janna Nichols (nwscubamom).
dtodd
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Re: Red Rock Crab Behavior Question

Postby dtodd » Mon Feb 06, 2017 2:10 pm

Mpenders
That was at the Junkpile last February 13th. A couple of octo researchers have weighed in on it and believe it to be an attempted cannibalism event.

dtodd
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Re: Red Rock Crab Behavior Question

Postby dtodd » Mon Feb 06, 2017 1:47 pm

Thanks Greg!

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Greg Jensen
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Re: Red Rock Crab Behavior Question

Postby Greg Jensen » Sun Feb 05, 2017 3:59 pm

Her eggs are recently extruded (orange) so nowhere near ready to hatch, and wouldn't be doing it in this position anyway.

I can see she has some large barnacles on her- my guess is that she somehow got flipped over and is so top-heavy from barnacles she couldn't right herself, and is too tired from trying to still be kicking.

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H20doctor
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Re: Red Rock Crab Behavior Question

Postby H20doctor » Sun Feb 05, 2017 1:46 pm

i would say that crab is 99% on the way out of life ... the fact its upside down and not moving means its sick and dying ... if you look at the behavior of a crab , either a red rock or a dungee .. crabs are either in the sand hiding, or out and about walking and eating .. when you approach a crab they go into defensive mode and run off , or throw up some pinchers to say " Hey Back Off !! "
NWDC Rule #2 Pictures Or it didn't Happen

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mpenders
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Re: Red Rock Crab Behavior Question

Postby mpenders » Sat Feb 04, 2017 1:56 pm

I'm no crab expert, and didn't stay at a Holiday Inn Express last night - so I'm out.

However, the link at the end of your vid to your GPO Interaction vid looked interesting....



Wow! Way cool encounter. When & where did this happen?

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YellowEye
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Re: Red Rock Crab Behavior Question

Postby YellowEye » Sat Feb 04, 2017 9:11 am

Very interesting.
I think I've seen them (at least other crabs) release eggs whilst standing up before. And they twitch down there as they do.

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ScubaJess
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Re: Red Rock Crab Behavior Question

Postby ScubaJess » Sat Feb 04, 2017 9:11 am

Very fascinating! I hope she's ok :)
Did you see any sea spiders?
Live Long And Prosper!!!

dtodd
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Red Rock Crab Behavior Question

Postby dtodd » Sat Feb 04, 2017 8:55 am



Found this upside down gravid red rock crab at the Junkpile a few weeks back
As you can see from the video her mouth parts are moving and there is an occasional movement in her legs. I observed her for several minutes and there was no change in the behavior pattern.
What is going on here?
Is she dying?
Getting ready to for her eggs to hatch?

I sure wish there was a crab expert on this board. :) Greg Jensen?


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