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!!!

Stay Warm underwater with the Weezle Extreme Plus undergarment! Please let me know if you would like to order one or have any questions. :luv: :partydance: :eric: :taco:

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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