Rogo-tumu & Life in the South Pacific

Tall tales of sea demons and sea monsters appear to have captivated the human psyche in cultures all around the world. In Polynesian mythology Rogo-tumu-here is known as the demon-octopus. The legend goes that Rogo-tumu-here captured the daughter of the ocean goddess Faumea and carried her to the depths of the ocean. She was rescued when Faumea “withdrew the wind into the sweat of her armpits” and harnessed the energy to kill Rogo-tumu-here.

So I discovered this story while trying to look up different names and words for octopus in Tahitian. I’ve finally seen a couple of these incredible creatures and I wanted to not only show pictures and talk about them, but also bring in some Polynesian culture as well. The more I read into Polynesian mythology, the more intriguing it became.  It’s amazing how different cultures perceive and indulge in the world.


Here’s an octopus we found early in the summer, sitting right underneath the dock. Of course, immediately I put my face in the water and tried to get a good picture. 


After one of the dives we did at Gump Reef (to count the settlement of the damselfish, Dascylllus trimaculatus), I swam around a bit more. To my excitement, I found an octopus! As I watched him, the most incredible part was that I noticed how intensely the octopus was watching me back. If I got too close, he’d hide in his hole. As I swam back, he’d poke his head back out and watch me! The more I moved away, the more he came out of his hole to look at me. After a while of this, I was able to get closer and closer without him going back into his den. Ahh it was amazing.


He’s difficult to see in the photo, but if you look closely you can make out his eyes. You can see how incredible these animals are at camouflage, the same one can look red, brown, or speckled. They can also change the texture of their skin to match their surroundings. What a remarkable feat of evolution.

Time here is flying by! I can’t believe I’ve already been here for a month! I have been enjoying everything about this place – the island, the research, the people. I have already met so many wonderful people, some graduate students, some postdocs and some principal investigators of their own labs at universities across the country. It has given me so much insight into other areas of research and it’s been so inspiring to watch so many people fully into their careers and loving every single thing they do.

And yes I’m here in Moorea, in a place more beautiful than I could have imagined, and yes someone is actually giving me money to scuba dive every day, but the work we do every day is not always glamorous. My hands continue to get more cut up each day due to handling cages underwater, cutting off zip ties, scraping off corals, building things, cleaning things, bumping into things. I’ve also spent numerous hours the last couple days in the lab putting aluminum weigh boats into an oven where they get muffled at 665 degrees F for four hours (to remove all carbon material), moved them to a drying over (so they remain as “sterile” as possible and don’t absorb water), then weighed all 220 boats, twice, twelve at a time using tweezers and keeping them in desiccant containers between weighing. Oh, and the weights had to be within 0.0003 g of one another, or else they had to be put back in the drying oven and re-weighed the next day.  The reason we’ve been doing all of this is because we collected algae samples from an underwater cage experiment that ended this summer. The algae will be filtered onto a filter paper, placed in the drying oven for three days, and then placed in the muffler. The muffler burns the organic carbon from the sample, so the difference in weight between the initial sample and the final tells us the amount of organic carbon in the algae. All this work is part of the process of science: ask questions, think about ways to answer them, collect all the data that you can, and then try to figure out what it means.

So in order to get all the algae samples, we had to go out to the field and collect the experiment. Today, we collected six plots, and it took us nearly four hours of bottom time at over 40 feet deep… Long day today! However, I did get to see two huge eagle rays swim past me, effortlessly and gracefully. I also saw more beautiful nudibranchs!



So here’s an idea of what the fore-reef looks like. It’s very blue! Driving out to our dive sites, we can see the sea floor, nearly 50 feet below us. On the clearest of days, you can see the fish swimming along the bottom. There are also beautiful shells galore, like the spider conch (Lambis truncata) above.


This is a coral head that’s almost 90 feet underwater. Still crystal clear blue and you can see the waves at the surface.

Once we brought all the cages back, some of the other undergraduates and I scoured the tubs the cages were held in, looking at all the incredible invertebrates that make their homes out of the corals.


This is what we’ve found…. so far…



This is called a squat lobster! (Galathea pilosa)



This is a sea hare, Stylocheilus striatus. Sea hares are a type of mollusk (like snails, mussels, clams, etc.). Unlike snails, sea hares do not have external shells, although they do contain a reduced internal shell. Being mollusks, they are also related to octopus. Sea hares can expel ink in times of stress to ward off or confuse predators. In California, we have two species of sea hares, both fairly large species. Here, I’ve been finding them much smaller, yet in much greater diversity of species.



Here’s another sea hare, Bursatella leachii. It’s incredible to be in Moorea where the diversity of everything is simply spectacular

So far, we’ve processed five plots (out of a total of ten). I’ve seen even more beautiful crabs, shrimps, snails, and even fish coming out of the corals. My plan is to bring my camera out the next time I get the chance and snap even more photos of what I’m seeing!





8 thoughts on “Rogo-tumu & Life in the South Pacific

  1. I cannot begin to describe how entrenched I become when I read your posts! Your comments, knowledge and photos (with captions) leave me speechless! It must be so interesting to see just some of the types of careers that can be pursued. I need to catch up on some of the earlier posts now. Great job Sweetie!

    • Thanks Uncle Bob! This comment makes me so happy 🙂 I love hearing from you guys at home! I really hope everyone is enjoying it, I’m definitely writing it for all of you!

  2. Evan introduced me to your blog today and I am so thrilled he did. Your writing is so detailed, I really appreciate that. Without being able to talk to Evan, it is hard to understand the everyday life going on there, so I really appreciate your details. If you don’t mind I will share this with our family, as we are all so fascinated with all that Evan is doing 😀 Thanks!

    • I am really glad you are enjoying it! Feel free to share it with whoever is interested! I love being able to share this experience as well as teach more people about the work we are doing. Also, lots of the great photos I’m getting are from Evan pointing out stuff to me so I’ll be sure to keep giving him credit for that!

  3. 😀 Evan’s pictures are amazing… I love seeing all the different creatures and the beauty of the ocean. We all are learning so much ! Thanks again for the blog!

  4. Hi Jaclyn! I am really enjoying your blog. I wanted to get your permission to you use one of your photos of the Stylocheilus striatus ( for a paper I am writing in regards to the affects of boat noise on embryonic development. If yes, I want to give credit where credit is due. I can link back to this page, or place a name. Please let me know if I have your permission to use the photo and how you would like it cited. Thanks so much! – Kim

    • Hi Kim, thanks so much for reaching out to me. Yes, you are welcome to use that image! It’s up to you whether you’d like to link the page back to me or just put my name, Jaclyn Mandoske, I’m happy with it either way. I appreciate your interest in my blog and photos and it sounds like a great and interesting research paper. Best of luck!

  5. Pingback: Boating Noise Negatively Affects Marine Species: Sea Hares

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