> I know
>that it had become established in California and has
>since been eradicated (presumably).
Yes, the latest cores and surveys showed no fragements in the two locations.
CA is in the process of removing all Cauplera species from sale in California since many exclusion and control personnel are not able to distingush the species and mnay varieties in the genus. At the present time, there are 9 species banned in CA. This year we hope to banned the genus for sale to aquarist. The aquarist have some good alternative marine macros that are easier to culture for their needs which is generally filtering the salt water aquariums.
The rapid response plan that was implemented here in CA was the main thing that reduced the cost and increased the effectiveness. Much easier to treat 10 square meters than 100,000. The Mediterranean situation apparently did not follow this rapid response plan. "If we'd only we had known......"
Control and eradication can be accomplished and successful in some cases if the weed makes it past exclusion, in every case is cheaper and more effective the sooner they begin treatment. We were lucky though, if it gets into the rocky intertidal, treatment will be much more difficult, if not impossible.
The infestation has cost about 5 million dollars to date to control and eradicate.
I am unaware if it might live in the East coast, certainly further south it does well(see link below). As aquarist habits and needs move away from this species/genus as well as increased public awareness, I hope there will far less threat.
There is an exotic Cauplera in Florida.