Range extension and reproduction of the barnacle Balanus perforatus in the eastern English Channel

Abstract

The distribution of the warm-water barnacle, Balanus perforatus, was surveyed along the south coast of England and the north-east coast of France between 1993 and 2001, repeating work carried out between the 1940s and 1960s. The species has recovered from catastrophic mortality during the severe winter of 1962^1963 and was found over 120 km (UK) and 190 km (France) east of previous records on both sides of the Channel. The presence of the species in the eastern Channel refutes suggestions in the 1950s that larvae, and hence adults, would not be found east of the Isle of Wight because of reproductive sterility close to the limits of distribution. Brooding of specimens translocated to Bembridge, Isle of Wight, commenced in May, earlier than previously observed in British waters, and continued until September. The stage of embryo development at Bembridge in mid-August was comparable to that of the large population at Lyme Regis, Dorset 100 km further west. However the size of brood per standard body weight was greater at Lyme Regis. Factors in£uencing the rate of colonization and further geographic range extension of the species as a possible result of climate change, are discussed. INTRODUCTIONBalanus perforatus Bruguie' re is one of the larger barnacles of European coasts. It usually occurs in the lower half of the littoral zone and may extend into the sublittoral. It is found in variable density on a wide range of hard substrata along wave-beaten shores and in ria-type estuaries (Norris & Crisp, 1953;Lewis, 1964). It is a southern species, occurring in the Mediterranean and along the eastern Atlantic seaboard from south-west Wales to West Africa, but has not been found in Ireland (Lochhead, 1936;Crisp & Southward, 1953). Earlier surveys in the English Channel reported the species as common in south-west England and along the coast of Brittany, with eastern limits approximately mid-Channel in the vicinity of the Isle of Wight on the English side, and Cherbourg on the French coast (Fischer-Piette, 1936;Crisp & Southward, 1958;Lewis, 1964;Stubbings & Houghton, 1964). There are early records of the species on piers at Blankenberge and Oostende, Belgium (Pelseneer, 1882) and in 1982 it was found at Dunkirk on mussel ropes (Davoult et al, 1993). The species is regularly found on £oating objects washed ashore in the southern North Sea and between 1996^1998, four specimens were found fouling the undersides of buoys o¡ the Belgian coast (Kerckhof & Cattrijsse, 2001). The status of specimens collected from buoys o¡ the Dutch coast and referred to as Balanus perforatus (Buizer, 1978) is confused (Kerckhof & Cattrijsse, 2001).Little has been published on the ecology and reproduction of B. perforatus. Field studies are di⁄cult as the animals often occur in cryptic habitats such as crevices and beneath overhangs. Norris & Crisp (1953) found fertilized egg masses in the mantle cavity between midJune and August at Torbay, Devon. Egg development was rapid and nauplii were liberated into the plankton in late June with settlement ...

Influence of recruitment and temperature on distribution of intertidal barnacles in the English Channel

“…Large range extensions of other southern species have been observed in the eastern Channel (Balanus perforatus, Herbert et al, 2003;Gibbula umbilicalis, Hiscock et al, 2004 (Moschella et al, 2005) is less easy to explain considering their short pelagic life of 4-5 days (Fretter & Graham, 1994). However G. umbilicalis, being mobile, may tolerate broken and boulder shores better than barnacles and thus able to bridge gaps in solid substrata.…”

Temporal differences across a bio-geographical boundary reveal slow response of sub-littoral benthos to climate change

“…Climatic conditions in the English Channel have changed considerably during the 20th century, with initial warming until the 1950s, a period of cooling after 1962 and significant warming since the 1980s (Luterbacher et al 2004). While the consequences of climatic change have been relatively well documented for the western English Channel for fish (Southward et al 1988, Genner et al 2004, plankton (Southward 1984, Pitois & Fox 2006, Gomez & Souissi 2007, Beaugrand et al 2009) and inter-tidal benthic communities , Herbert et al 2003, Mieszkowska et al 2007, no such data exist for sub-tidal benthic organisms. However, the large-scale surveys of Norman Holme (Holme 1961(Holme , 1966 do provide a baseline for the distribution of benthic species against which current patterns can be compared.…”

Cirripedia of Madeira

“…Species with full planktotrophic development through six naupliar stages (the majority) may live from several days to a few weeks in the plankton, depending on temperature, but this still limits their dispersal. The absence of Balanus perforatus from both Madeira and the Azores confirms that this species is unable to cross sea barriers (Crisp and Southward 1953), in spite of its capacity to occur sub-littorally to 40 m depth and settle on floating objects (Herbert et al 2003;E.I.S. Rees, personal communication).…”