VIDEO: Octopus and kelp crab interaction

[drbill]

About two weeks ago I was doing one of my frequent night dives when I encountered and started filming a male southern kelp crab wandering around on the bottom (they usually crawl into crevices when my video lights hit them). I obtained 13 minutes of edited footage of this crab. At one point I was shocked to see something fly in from the left side of the frame and try to capture the crab for dinner. Apparently the crab fought back and pinched the octopus on its mantle with its left claw (hidden from view). Pretty neat interaction!

[video=youtube;oBrwgUFHXQg]http://www.youtube.com/watch?v=oBrwgUFHXQg&feature=youtu.be[/video]

 

[Vegan Shark]

Wow, incredible scene.

Bill, have you noticed fish adversely affected by divers' lights on night dives? I'd love to see all the stuff that only happens at night, but have reserves about shining my light on fish and stunning them with the brightness.

 

[gert7to3]

That was a pretty ballsy move on the part of that octopus. It didn't seem big enough to try tackling a crab that size.

Dr. Bill, have you tried to shoot at night with red lights and convert the video to black & white? Just thinking if you are trying to record behavior that might suffice.

Speaking of fish adversely affected by divers' lights, in Bonaire you will frequently find yourself buzzed by tarpon and schoolmasters lining up on some tang or squirrel fish caught in your light beam. Attached is a badly framed (there was a lot of unexpected action) sequence of a schoolmaster which shoved past me to nail a blue tang I illuminated in some coral. First the schoolmaster pinned it to the bottom, the last I saw it was taking that poor tang off to the kitchen.

 

[drbill]

Yes, certainly there are fish that are affected negative by the video lights at night. I do try to avoid shining them too brightly on any fish or invertebrates with advanced eyes like octopus. I keep the lights on lowest power throughout the dive and generally film from a distance (8-15 ft). There are also fish which are "positively" affected by the lights suc as kelp bass that target blacksmith illuminated at distances of up to 30 ft from me... of c9ourse that's a negative impact for the blacksmith if they are captured thanks to the lights.

 

[Fundive123]

Crab lives another night! I like how at the end he postured himself as if saying "Want some more!? Come get it!" Cool clip drbill.

 

[poomero]

That's a really cool video thanks for sharing it.