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An ex-Royal Navy frigate, HMS ‘Scylla’, was placed on the seabed in Whitsand Bay, south Cornwall on 27 March 2004. After five years, the reef supported a mature steel wreck community. The colonization of the reef showed wide fluctuations in species abundance in the first two years but, by 2006, most species that dominated or characterized the reef after five years had settled. Significant colonization events included settlement of barnacles, tubeworms and hydroids within a month and remarkably high settlements of the sea urchin Psammechinus miliaris and the queen scallop Aequipecten opercularis in the first year together with starfish Asterias rubens, solitary sea squirts and ephemeral algae. The plumose anemone Metridium senile, a characteristic species of wrecks, arrived in late summer 2004 but the widely distributed dead man's fingers Alcyonium digitatum was not observed until spring 2005. Wrasse were slow to colonize the reef but were established in small numbers by the end of 2007. Sea fans, Eunicella verrucosa, were first observed in August 2007. The species count for the reef stood at 263 taxa by the end of March 2009. The inside of the reef remained poorly colonized even after five years. Areas coated with tributyltin (TBT) antifouling paint only had colonization where the paint had flaked-off or on non-toxic paint markings, but with some indication that colonization may be occurring by a very few species especially near to non-TBT areas. Many species characteristic of natural reefs had not settled and neither do they occur on older wrecks including branching axinellid sponges, some cushion sponges and the yellow cluster anemone Parazoanthus axinellae. The artificial reef developed a community that was distinctly different to nearby natural rock reefs and such artificial structures should not be considered as a replacement for damaged or destroyed natural habitats.

New records are given of the occurrence of the warm-water barnacle Solidobalanus fallax in Britain and Europe. This barnacle is not found on rocks or stones, but settles on biological substrata, including algae, cnidarians, bivalves, gastropods and crustaceans. It also settles on plastic bags and nets, plastic-coated objects such as crab and lobster pots and octopus pots made of ceramic or plastic. With one exception the species was unrecorded in Europe before 1980; it may have increased in abundance during recent years as a result of rising temperatures. The cyprid larvae, which can metamorphose on plastic Petri dishes, appear to be adapted to seek out ‘low energy’ surfaces. One of the habitats colonized by S. fallax is the sea-fan Eunicella verrucosa, where it seems to have increased in recent years, possibly to the detriment of the cnidarian host. Solidobalanus fallax has the potential to be a serious pest of fish-farming structures to the south of Britain.

Simnia patula (Pennant)=0vula is common feeding on Ahyoniwm digitatum and on Eunicella verrucosa, trawled in Plymouth waters. Mr. E. A. Todd records in the 1904 Plymouth Fauna List (Plymouth Marine Invertebrate Fauna, Journal of the Marine Biological Association, VII, 1904), which is quoted in the new fauna list (1931, Marine Biological Association), that “spawn probably belonging to this species has been found in April, June-July.” This spawn is also well known to other members of the staff of the Laboratory and it is often found with the Simnia itself. It is now quite certain that it is the spawn of this mollusc, for it has been deposited in a plunger-jar on the glass and on Alcyonium (Jan. 19/20, 1932), and hatched out Feb. 21/22, 1932; it has been hatched out in the Laboratory, the larvae distinguished in the plankton and reared until the crawling stage in a plunger-jar; and young stages which bridge the gulf from larva to adult have also been found. The adults will live for months in a plunger-jar feeding voraciously on Alcyonium. The life-history is described here for the first time. It is very interesting because it is quite unlike that of Trivia euro-pea recently described (Lebour, 1931b), although the two are placed in the same family. Trivia bites holes in compound ascidians and lays its eggs in vase-shaped capsules embedded up to the neck in the ascidian, and these hatch out into larvae having accessory shells rather like those of Lamellaria but with distinct differences. Simnia lays its eggs in a single layer of capsules, spreading over the Alcyonium for an inch or more in an irregular roundish mass (Text-figure 1).