Species - Rapana venosa


  • Rapana venosa (Valenciennes 1846)
  • Rapa whelk
  • Giberto and Bruno (2014) noted the southward extension of the species in South America, and reported range extensions along the Argentine coastline (based on 2010-2013 observations), including the finding of an individual in Mar Chiquita lagoon in central Argentina.

  • To date, Rapana venosa is unknown from Australian waters. Its native distribution includes the temperate Sea of Japan, the Yellow Sea, the Bohai Sea, the East China Sea to Taiwan in the south, and Peter the Great Bay off Vladivostok in the north (Mann and Harding, 2003). Its invasive range now covers areas of the Black Sea, the Aegean, Adriatic and Mediterranean Seas (Drapkin 1963, Chukhchin 1984, Zolotarev 1996, Mann et al. 2004) and the Chesapeake Bay, USA (Harding & Mann 1999).

    R. venosa favours compacted sandy bottoms where it can burrow almost completely. The native habitat is a region of wide annual temperature ranges. Escaping cold waters in the winter, this species may migrate to warmer, deeper waters, thus evading cool surface waters. It is highly fertile, and extremely resilient against fluctuating environmental conditions; for instance, it tolerates low salinities, water pollution, and oxygen deficient waters (Ritcherson and Benson, 2021).

    R. venosa is a predatory gastropod mollusc with a globose (rounded) and heavy shell with a very short spire and large last adult whorl. The species is grey to brownish with irregular dark blotches, which appear as an interrupted pattern upon the sculpture of dense spiral cords.. The shells of most specimens have a distinctive black ‘veined’ pattern. However, local variations in colouration may occur, depending on the substrate of its habitat. The aperture of the shell is large, ovate and slightly expanded, and the thin outer lip has a fluted edge corresponding to the external spiral cords. An important diagnostic feature is the deep orange colour in the aperture (not present in juveniles). Fully grown specimens have been recorded with a maximum shell length of 180 mm (USGS, 2002; CIESM, 2003; ICES, 2004). Males tend to be larger than females (Sağlam and Düzgüneş, 2014).

    While shells of the species have been observed in New Zealand (Powell, 1979; Mann et al., 2004), R. venosa has not to date been recorded in Australia. Given its preference for temperate conditions (as inferred from distribution range, both native and introduced) it is likely that it poses the greatest risk to southern Australia. It is considered highly unlikely that it is able to establish in tropical Australia, yet vigilance is nevertheless advised.

  • https://www.marinepests.gov.au/pests/identify/rapa-whelk
  • Unknown
  • Not recorded
  • North-west Pacific

    The native distribution of R. venosa includes the temperate Sea of Japan, the Yellow Sea, the Bohai Sea, the East China Sea to Taiwan in the south, and Peter the Great Bay off Vladivostok in the north (Mann and Harding, 2003).

     

    R. venosa was first discovered outside its native range in Novorossiysky Bay in the Black Sea in the mid-1940s (Drapkin 1963) and in the ensuing six decades it had spread throughout the Aegean, Adriatic and Mediterranean Seas (Drapkin 1963, Chukhchin 1984, Zolotarev 1996, Mann et al. 2004), and entered the Chesapeake Bay, Virginia, (Harding & Mann 1999).

    The species is listed among the 100 of the ‘worst invaders’ in the Mediterranean (Streftaris & Zenetos, 2006).

    ‘Plasticity in the duration of the pelagic larval phase, the absence of specific larval settlement cues, broad dietary options in the early post-settlement stage, rapid growth to possible predation refuge, relatively early onset of sexual maturity, high fecundity, considerable longevity, and tolerance of challenging environments with respect to anthropogenic stressors make R. venosa a formidable invasion threat’ (ICES, 2004).

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  • <p>Image of <em>Rapana venosa</em> being held in the palm of a hand. This image gives a good representation of the potential size of the species.</p>

    Image of Rapana venosa being held in the palm of a hand. This image gives a good representation of the potential size of the species.

    Copyright Notice: Juliana Harding VIMS. Acknowledge: true
  • <p>Front and rear view of a <em>Rapana venosa</em> individual.</p>

    Front and rear view of a Rapana venosa individual.

    Copyright Notice: Eddie Hary. Acknowledge: true

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