Distribution of two species of lugworm (Arenicola) (Annelida: Polychaeta) in South Wales

Abstract

This study demonstrates that the two species of lugworm, previously classified as Arenicola marina occupy distinct zones within sandy beaches around South Wales. Arenicola marina (sensu stricto) or blow lug, is found higher up the shore, tending to be concentrated at mid-tide level, whilst A. defodiens Cadman & Nelson-smith, 1993 or black lug is most numerous at or below mean low water of spring tides and, unlike A. marina in this area, also apparently extends subtidally. Arenicola marina is found in estuaries, unlike A. defodiens, and seems to inhabit slightly less exposed beaches. Degree of sorting, mean and median particle size do not appear to be a significant factor in determining lugworm distributions. Some possible explanations for these observed differences, including differences in burrow depth and salinity tolerance, are discussed.

Control of oocyte maturation, sperm activation and spawning in two lugworm species:Arenicola marina and A. defodiens

“…by a variety of ecological, morphological and genetic criteria (Cadman & Nelson-Smith 1990, Cadman 1997. However, until now, no direct comparisons or exChemical induction of oocyte maturation periments have been undertaken to examine whether these differences extend to the reproductive biology of Maturation of each species' oocytes only occurred the 2 species.…”

“…The recent work of Cadman & Nelson-Smith (1990 and Cadman (1997) has shown, through the examination of a number of morphological, ecological and genetic characteristics, that this distinction was valid, and consequently the 'laminarian' variety has been classed as a separate species, Arenicola defodiens (Cadman & Nelson-Smith).…”

“…A. manna has a wide distribution, being found in sandy beaches and estuaries across Northern Europe (Wells 1963, Beukema & . The distribution of A. defodiens is, however, largely unknown, with only the original work of Gamble & Ashworth (1898) and a recent study by Cadman (1997) having examined its distribution and abundance. In both South Wales (UK) and several sites on the Northumberland coast (UK), locations where A. defodiens only are present are relatively common, but there are also a number of sites where both species exist sympatrically.…”

“…A. defodiens was also absent from all the estuaries investigated, in contrast to A. marina, densities of which are often at their highest in estuaries. Where both species coexist, A. defodiens are usually found at a lower position on the shore (in relation to tidal height) than sympatric A. marina (Cadman 1997).…”

Distribution and abundance ofAbarenicola affinis(Arenicolidae, Polychaeta) in tidal inlets of Otago, New Zealand

“…Hobson 1967;Beukema & de Vlas 1979;Swinbanks & Murray 1981;Cadman 1997;Reise et al 2001). In the European Wadden Sea, Arenicola marina covers more than 70% of 4700 km 2 tidal flat area at an average density of 20Á40 individuals per m 2 (Beukema 1976;Beukema & de Vlas 1979;Reise et al 1994), representing the largest known lugworm population (an estimated 1 billion, Reise et al 2010).…”