What Would Happen If...

[dwashbur]

I was talking with another diver today and he said his most memorable experience with a giant pacific octopus came from a female that was probably sitting on eggs. She was a bit pale, which is what made him suspect it. But he took a crab and held it out to the octo, and she took it. That made me ponder a hypothetical question, to wit:

We know the female octopus dies shortly after the eggs hatch. At least part of the reason for this is that she doesn't eat while she's guarding them. Hence, she only mates and reproduces once. I can't help wondering what would happen if she somehow was able to get food (read, somebody fed her the way this fellow did, but on a regular basis) during the incubation period. Would she still die? Or is it possible she could recover, perhaps even to mate again? Has such a thing ever been studied? I'm not advocating anything here, just asking your basic hippopotamus question (or whatever it's called).

[Greg Jensen]

Unfortunately yes, it would still die. It's a hormonal, 'programmed' death, not the result of the octopus not feeding. The optic glands are responsible for this, and if they are surgically removed the octopus resumes feeding and lives much longer.

[nwscubamom]

Optic glands?!?! As in, the EYE? That controls the life cycle?

Weird! Are there other critters that are similar?

- Janna (always amazed at Greg's cool tidbits)

[OreCoastDiver]

Squid, both market squid and Humboldt (red devil, red rocket).

[Sounder]

"Olive," the GPO who "Olive's Den" is named for was a well-known and visited octopus in Cove 2. When she was on eggs, divers repeatedly brought her crabs and such but she never took them... at least this is the story I'm told from trusted friends.

Greg - what exactly do you do? What's your background? Sure, you've got excellent fish ID skills, and you seem to know your way around a critter discussion... but optic gland studies in octopuses?! Wow, that's a piece of trivia I would have NEVER guessed!!

[Greg Jensen]

My area of specialization is in decapod crustaceans (crabs & shrimps), particularly hippolytid shrimps- the little guys. I taught the shellfish biology class at the UW for over 20 years, which covered crustaceans, molluscs, and echinoderms, so I had to keep up to date on all those groups. Now (alas) I no longer teach that class but I still teach a crustacean biology class every other year up in Bamfield on Vancouver Island. I've always been interested in the behavior and ecology of local fish and taught a fish biology class for a few years up at Shannon Point marine lab.

[Sounder]

My area of specialization is in decapod crustaceans (crabs & shrimps), particularly hippolytid shrimps- the little guys. I taught the shellfish biology class at the UW for over 20 years, which covered crustaceans, molluscs, and echinoderms, so I had to keep up to date on all those groups. Now (alas) I no longer teach that class but I still teach a crustacean biology class every other year up in Bamfield on Vancouver Island. I've always been interested in the behavior and ecology of local fish and taught a fish biology class for a few years up at Shannon Point marine lab.

Cool. That sounds about like what I was expecting. The surgical removal optical gland extending life definitely was a beyond REEF fish ID!!

Thank you for your participation here - I enjoy reading your posts and we're fortunate to have your expert opinion!!

[coachrenz]

Greg is a pretty humble guy.

I found this http://artedi.fish.washington.edu/okhot ... Jensen.htm as a bio from 2001. Pretty dang impressive.

If you do a Scholar Google search on his name, Gregory C Jensen, you will see that he has quite a few scholarly papers published and he is referenced in many more.

Dude knows more about more stuff than most people don't know about. In fact, he has probably forgotten more stuff than I will ever hope to know.

[nwscubamom]

While we're singing his praises - I know I've learned more from him regarding fish ID than any other biologist around in the NW. He knows his stuff. (and he's an excellent photographer too).