The genus Boccardia (Polychaeta: Spionidae) associated with mollusc shells on the south coast of South Africa

Abstract

Three species of Boccardia (B. polybranchia, B. pseudonatrix and B. proboscidea) were associated with mollusc shells on the south and south-east coasts of South Africa. Boccardia polybranchia was widely distributed along the coast and falls within the known distribution range of this species. Comparisons with material from other, international, locations showed that some specimens have been misidentified. No characters could be found to characterize distinct species for different regions within the range of B. polybranchia, as currently recognized. Boccardia pseudonatrix was found only at the most eastern site, increasing its known distribution range. Boccardia proboscidea, a non-indigenous species, was found only on abalone farms and was most abundant in the west.

Polydorid polychaetes on farmed molluscs: distribution, spread and factors contributing to their success

“…Since its initial identification as a pest of oysters by Haswell (1885), B. polybranchia has been recorded as a pest of C. gigas in France (Ruellet 2004, Royer et al 2006 and My ti lus edulis in Australia (Pregenzer 1983). There is, however, much confusion in the literature around this species (Blake & Kudenov 1978, Simon et al 2010 and it probably includes several morphologically similar species. Additionally, it has not been recorded with oysters in Australia since 1983 (Pregenzer 1983, Walker 2014), while the photograph provided in Ruellet (2004, their Fig.…”

“…It is clear that polydorids can be difficult to identify, especially for many aquaculturists who lack taxonomic training and access to the literature. For example, South Afri - can farmers initially assumed that locally cultured abalone were infested by a 'Polydora' species, when they were, in fact, infested by P. hop lu ra, B. proboscidea and D. capensis (Simon et al 2006, Simon et al 2010. It is therefore imperative that an alternative means to identify worms is developed, and that a molecular database of polydorids, using common DNA markers such as 18S rRNA, 28S rRNA and COI, be generated.…”

“…For example, in South Africa, Chile and Australasia, farmed molluscs were typically infested by fewer species than are present on wild molluscs occurring close to farms (e.g. Sato-Okoshi & Takatsuka 2001, Simon et al 2006, Sato-Okoshi et al 2008, Simon et al 2010, Simon 2011, Boonzaaier et al 2014, SatoOkoshi et al 2015. Similarly, molluscs grown in on-shore culture systems were infested by fewer species than those grown off-shore (Simon, 2015).…”

Boccardia proboscidea and Boccardiella hamata (Polychaeta: Spionidae: Polydorinae), introduced mud worms new for the North Sea and Europe, respectively

“…The North Pacific coastlines of Japan and North America are considered to be the original distribution range of B. proboscidea (see Simon et al, 2010). The occurrence in Hawai'i (Bailey-Brock, 2000), Australia (Blake & Kudenov, 1978), New Zealand (Read, 2004), South Africa (Simon et al, 2010), Argentina (Jaubet et al, 2011), Maine (Bailey-Brock, 2000), Spain (Martínez et al, 2006) and Scotland (Hatton & Pierce, 2013) is ascribed to humanmediated introductions, mainly related to transfers of cultured shellfish. Boccardia proboscidea was inadvertently transported to South Africa on Haliotis rufescens Swainson, 1822, which was imported from California in the late 1980s (Simon et al, 2010).…”

“…the genus Polydora and related genera, often raises concerns in oyster culture as several species in this group drill holes in calcareous substrata, such as mollusc shells (Hoeksema, 1983;Bailey-Brock, 2000;Ruellet, 2004;Simon et al, 2010). They can also form dense tube mats covering large areas in polluted or deteriorated habitats, smothering other sessile invertebrates (e.g.…”