FAQ
A contribution of The Cephalopod Page
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I occasionally get questions about rearing octopuses from eggs. This one is from Debbie Ingrao, a Senior Biologist at Mote Marine Laboratory in Sarasota, Florida. The following is actually condensed from several letters. I'm especially interested in this subject, along with the life history of cephalopods and the behavior of cephalopods.
Dear Mr. Wood, Dr. Clyde Roper from the Smithsonian National Museum of Natural History in Washington, D.C. suggested I contact you. I am a Senior Biologist at Mote Marine Laboratory in Sarasota, Florida. I work in the Benthic Ecology Department. During my 'free time,' I dabble in micro photography and octopi. Last October one of the aquarium staff brought me some newly hatched planktonic larvae which hatched in one of the display tanks. I have hatched O. joubini eggs before but had never seen paralarvae before. |
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| ('Paralarvae' refers to the small planktonic offspring of some cephalopods. Cephalopods, especially octopuses, that have a planktonic phase in their life cycle are often called 'small egged' cephalopods/octopuses)
To be perfectly honest I did not know planktonic hatchlings existed - I always thought all octo young were benthic immediately. The Mom (OctoMom) had been captured off Marathon Key and delivered to the aquarium approximately 2 weeks prior to her laying eggs in the skimmer of the display tank. I never got to see the eggs but the babies (OctoBabes) that I measured were 2.2 mm in length. When they all started hatching, the 135 gallon tank was milk white with OctoBabes for three mornings in a row. Most of the paralarvae were released to the wild, a few specimens given to me to photograph and some maintained in a tank in the quarantine area. Unfortunately we had no idea how to keep these specimens alive. We tried freshly hatched brine shrimp which we have readily available all the time but the OctoBabes were not interested. I am looking forward to hearing from you. Any information you could pass on would be greatly appreciated. Dear Debbie, I never did get to Mote Marine Lab (I'm from Florida). I do happen to have a Mote hand out on octopuses as well as information on becoming a summer intern. I'd be glad to help but you should realize that I've never reared planktonic octopus paralarvae. I have reared large-egged hatchlings such as O. briareus which is common in the Florida Keys. With Clyde Roper and Mike Vecchione as advisors, I tried to rear cephalopod paralarvae that were collected in the Gulf Stream and didn't have much luck as the specimens were too damaged in collection in the plankton net. Since then, I've been keeping up with the literature on rearing small egged octopods. The only person (that I know off hand - it's likely that some workers in Japan have also done this) who has recently succeeded in rearing paralarvae is Roger Villanueva. He worked with O. vulgaris and is a very nice/helpful guy. I can pass along his email if you like. Some of what I have to say comes from his papers. Also, anything you read on rearing other small planktonic cephalopods, such as hatchling squid, is likely to apply as Octopus paralarvae are thought to be somewhat similar in behavior and morphology. About half of all octopuses have planktonic offspring. For instance, all the octopuses in Hawaii have small eggs. Actually, there may be two species of 'O. joubini' - one with small planktonic offspring and one with large benthic offspring. According to Forsythe And Toll, the name O. joubini should be used for the small egged octo - not the large egged one which everyone calls O. joubini. I'll let the taxonomists fight this one out. As far as using Artemia (brine shrimp), Roger Hanlon found 26 or so studies that used Artemia and none of them had any success. I've tried pumping up Artemia with Selco, a nutrient adaptive, and then feeding them to O. briareus without any success. Live crustaceans are the way to go though. Villanueva used newly hatched zoeae of Liocarcinus and Pagurus. Any crustacean zoeae that is the right size and that you can get lots of should do - I was using sand fleas (Emerita) and Brachyuran zoeae when I was trying to keep collected paralarvae alive at the Smithsonian Station at Link Port. Copepods would also make an excellent food. Appropriate sized plankton could also be used. Small egged hatchlings are much harder to rear. I suspect that food and filtration are the major stumbling blocks in their culture. BTW, are you running an open or a closed system at Mote? If you are running an open system and are filtering the water, you might be able to find small crustaceans in the filter backwash. Just another though... Glad to help. If you have more questions or just want to chat about octos, please drop me a note anytime. You realize that I'm going to want a behind the scene tour when I visit ;-), I love aquariums! Dr. James Wood |