This ovigerous mass was found 10 meters deep, in the Tyrrhenian Sea, near the Argentario Mount, but it was also found in the harbour of Trieste in 2009. Which invertebrate could have produced it?
I would look within Annelids. I have in mind the Polychaeta Phyllodocidae who have the same eggs but in green. These orange eggs may come from a related species.