Interview with a Phyllorhiza punctata Jellyfish: Insights from the Ocean’s Drifter

Interview with a Phyllorhiza punctata Jellyfish: Insights from the Ocean’s Drifter


CGD: Welcome, everyone, to today’s unique interview. We have a very special guest joining us live from Koh Tao's underwater world!  A Phyllorhiza punctata Jellyfish!! Let's dive right into it. First off, can you tell us a bit about yourself and what it's like to be a Phyllorhiza punctata jellyfish?


Sea Jelly: Thanks for having me! It's great to be here. I'm Phyllorhiza Punctata, also known as the Australian Spotty or White Spotty Jellyfish, part of the Rhizostomatidae family. But hey, you can just call me Sea Jelly! Well, being a rhizostome is quite an experience. Unlike many of our jellyfish cousins, we lack tentacles around the bell's edge and instead have a unique structure with many small, frilly mouths on our oral arms. We drift with the ocean currents, pulsating our bells to move gracefully through the water.


CGD: That sounds fascinating. Can you explain how your body works, especially the unique aspects of a rhizostome Jellyfish?



Sea Jelly: Certainly! Our bodies are mostly made of water; about 95%, to be exact. The bell is our main body part and helps us move by contracting and relaxing. Instead of tentacles, we have eight highly branched oral arms that we use to catch food. Inside our bell, we have a simple digestive system known as the gastrovascular cavity, where we digest our food.


CGD: Speaking of feeding, how does a rhizostome Jellyfish catch and eat its prey?



Sea Jelly: Unlike our jellyfish cousins that rely on long tentacles, we rhizostome sea jellies have evolved intricate oral arms for feeding! These arms are equipped with tiny mouths and nematocysts, which contain stinging cells to capture and paralyze our prey. Our frilly mouths excel at filtering planktonic organisms from the water. Once stung and immobilized by our nematocysts, the prey is transported to our mouths for digestion. This efficient feeding strategy enables us to thrive in diverse ocean environments.


CGD: Some say you have no brain. How do you respond to that?



Sea Jelly: (Laughs) Well, it's true that we don't have a centralized brain like you humans do. Instead, we have a simple nerve net that helps us respond to our environment. You might say we think with our whole body! It works pretty well for us,considering we've been around for over 500 million years.


CGD: Fair point! How can you see without a brain?



Sea Jelly: Great question! We don't have eyes like you do, but we have specialized cells called ocelli that can detect light.This helps us navigate and maintain our position in the water. Think of it as having a built-in light detector rather than actual vision.


CGD:That’s a great way to put it. What do you think about scuba divers behavior when they encounter you?



Sea Jelly: Scuba divers are quite amusing creatures! Most of them are respectful and genuinely fascinated by us, which we enjoy. However, some can get a bit too curious and try to touch us. I have to say, I really don't appreciate those poking me with sticks: I mean, seriously! We'd much rather they admire us from a safe distance - after all, our stingers aren't just for show, you know!


CGD: Should we be scared of you?



Sea Jelly: Oh, no need to fear us! Sure, our stings can pack a punch, but we're not aggressive. As long as you give us some space and don't try to handle us, there's no reason to be scared. We’re just floating around, minding our own business.


CGD: Fair enough! What about your life cycle? How do rhizostome jellyfishes grow and reproduce?



Sea Jelly: Our life cycle is truly fascinating and complex. We start as tiny polyps firmly attached to a hard surface. From there, we reproduce asexually by budding. As time goes on, we undergo an awesome process known as strobilation, where we segment and release tiny ephyrae into the water. These ephyrae then mature into the medusa stage, which is the adult jellyfish that everyone recognizes! It's an incredible journey from being a stationary polyp to gracefully pulsating through the ocean currents as a medusa.


CGD: Speaking of reproduction, how do know...have  sex?



Sea Jelly: (Laughs) It’s not as exciting as it sounds! We release our gametes - sperm and eggs - into the water, where they meet and fertilize. No fancy dates or romantic dinners required!


CGD: Hmm, intriguing! But hold up... No brain, no eyes, no... sex? So, do you have a heart beating in there?


Sea Jelly: Nope, not a chance! We keep things straightforward. No heart needed when you don't have blood to pump. And guess what? No lungs either! Our skin's so thin, we soak up oxygen straight from the water. We navigate our world using signals from a nerve net called the "epidermal nerve net," which runs just beneath our outer skin layer, helping us sense and respond to our environment. Put it this way, we jellyfish like to keep it easy-breezy, just floating around, soaking in the ocean vibes without any of the usual vital organs! 


CGD: Very straightforward! Now, onto a lighter topic: How do you sleep?



Sea Jelly: Sleep? Who needs sleep when you're a jellyfish? We don’t sleep in the traditional sense. Instead, we enter a sort of rest phase where our activity slows down, especially at night. It’s our way of recharging without having to snooze like land creatures.


CGD: Interesting! And who are your best mates in the ocean?



Sea Jelly: Oh, I've got quite the crew! Juvenile fish and crustaceans often hang out around my bell for protection, Our symbiotic relationship is a win-win: they find shelter and transportation among my tentacles, taking advantage of my movement and protection without becoming prey, and I get some great company. Turtles, on the other hand, are a bit of a frenemy - they find us delicious, so we try to keep our distance!


CGD: That’s quite the social circle! What advice do you have for scuba divers when they encounter jellyfish like yourself?




Sea Jelly: Ah, divers, listen up! Admire us from a safe distance -we’re stunning but stinging. Remember, don’t touch, tease, or harass marine life; it stresses us out! Also, be mindful of your fins; avoid kicking up sediment or touching the reef, as it can harm delicate coral and disturb sediment-laying creatures. Our underwater home is delicate, you know!


CGD: Impressive advice, thanks Sea Jelly! Speaking of ocean etiquette, how do you feel about your jellyfish cousins who glow in the dark?



Sea Jelly: Well, thank you! Those glowing cousins of mine, they're something else, aren't they? Unlike us, they have special proteins in their bodies that emit light when disturbed. I must say, they add a magical touch to the ocean's nightlife! Personally, I prefer to keep it classic with my translucent elegance, but hey, to each their own luminescent style, right?


CGD: I’ve heard that jellyfish can sometimes appear in large numbers, known as blooms. Can you explain why this happens?




Sea Jelly: Yes, jellyfish blooms - some call them smacks or swarms too! While it's not something that happens often in Koh Tao, these blooms occur when conditions are perfect for our populations to boom.Things like water temperature, salinity, and food availability all play a role. Sometimes human activities, like overfishing and nutrient pollution, can also pitch in by reducing our predators and boosting our food supply. These blooms can be quite the spectacle, but they can also throw off local ecosystems and human activities.


CGD: What role do rhizostome jellyfishes play in the marine ecosystem?




Sea Jelly: Well, I don't like to brag, but we definitely play several important roles! As predators, we help control populations of smaller marine organisms. As prey, we provide food for a variety of marine animals, including sea turtles, some types of sharks, seabirds, and certain marine mammals like dolphins (etc..) Plus, when we gracefully meet our end, our decaying bodies help nourish the ocean floor, supporting life in the benthic community.


CGD:That’s quite an important role, indeed. Before we wrap up, is there anything else you’d like people to know about rhizostome jellyfishes?



Sea Jelly: I’d like people to appreciate the beauty and complexity of our existence. We may seem simple, but we are a crucial part of the ocean’s ecosystem. Also, while our stings can be unpleasant, they are just a part of our natural behavior. Respecting and understanding us can lead to a greater appreciation of the delicate balance within marine environments.


CGD: Thank you so much for sharing your world with us. It’s been an enlightening conversation, and I’m sure our readers will have a new appreciation for rhizostome jellyfishes.



Sea Jelly: Thank you for having me. It’s been a pleasure to share our story. SEA you guys!
PADI 5 Stars IDC Center

More than 50000 PADI Certifications


Our team is at your disposal for any questions about our articles or your order.


The management of our online payments is 100% Secure with Stripe


Free Shipping in Thailand

This website uses cookies to ensure you get the best experience on our website.