The image was sent to me by a diver. It was taken at a depth of 52m in Malta (Central Mediterranean). The 'sphere' was about 1 m in diameter and was moving with the currents. It seemed to be a 'shell' of jelly with no obvious structure. All I can think of is the remains of some gelatinous planktonic organism. Any ideas?
It's hard to say, but it looks like it could be the discarded mucous house of a giant larvacean. Apparently their mucous houses can be larger than a meter in diameter.
Thank you for the tip. I am familiar with larvaceans but I did not know that their houses could be so large. I'll look into whether we have any giant larvaceans in the Mediterranean.
In the Canaries I have seen very large mucous houses of diverse larvaceans, not so rounded and never so big. Anyway, in absence of more data I think than Mr. Holsen is right.
Salvatore Giacobbe sent me a personal message pointing me towards similar structures photographed in the Adriatic (http://www.dcpongo.com/e-ecostories.html#egg). I followed up on this and found additional information (see http://www.iups.it/la-teca-di-punta-campanella/ ). The 'sphere' photographed in Malta looks very much like these images of ommastrephid egg-masses, including the 'dark cylinder' running from one end of the sphere to the other.
While researching Daniel Holstein's suggestion I discovered that we do seem to do have a 'giant larvacean' in the Mediterranean, a species of Bathochordaeus but I could not find information as to where and at what depth it occurs. Photographs of discarded houses of such appendicularians I have seen are not spherical such as the structure photographed in Malta.
The most likely candidate is an ommastrephid squid egg-mass but we do not know which species produced it, however.
seems to be intersting, some gelatinous planktonic organism.but no idea,
To Dr. Schembri
We are looking into similar gelatinous spheres from the Norwegian coast, and are very interested in getting in contact With the observer. Could you please give me her/ his name and e-mail adress as soon as possible?
Kind regards, Halldis Ringvold
Look me up here: https://www.um.edu.mt/search and send me your personal e-mail address, please.
Hi
I would just like to inform you that we have included the Malta and Italian (from Punta Campanella) gelatinous sphere in Our article "Using citizen science to obtain data on large, floating gelatinous spheres from NE Atlantic, attributed to egg mass of ommastrephid squid (Oegopsida, Cephalopoda, Mollusca)" (Ringvold & Taite, 2018). The article will be published in the journal Marine Biology Research in a short while.
We discuss the findings of 27 large spheres but we are still in need of a tissue sample from divers in order to get evidence regarding which species who made them. Any divers who comes across such large gelatinous spheres, please let us know - and please provide us With a tisse sample and/ or a photo. Cut out a small tissue sample (a 1-euro coin size is sufficient) With your diving knife, and keep it as Cold as possible - until you are able to put it in a clean plastic bag in the freezer at home. Contact us for further instructions.
Regards, Halldis Ringvold
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