A NSW Government website

Rapa whelk / Veined whelk


The rapa whelk or veined whelk, is a large species of predatory snail with the shell reaching lengths of 18cm. The outside of the shell is usually grey to red/brown.

It is a versatile species capable of tolerating a wide range of temperatures, low salinities, polluted and oxygen-deficient waters. It can prey heavily on native shellfish and aquaculture species.


Rapa welk or veined welk / Rapana venosa

Photo credit: U.S. Geological Survey Archives, United StatesKey features:

  • Large heavy shell up to 18cm long with large opening
  • Outside shell colour varies grey to red/brown
  • Black vein-like pattern over whole shell
  • Distinctive deep orange interior

Known locations:

  • Not recorded in Australia


  • Tolerates wide range of temperatures and salinities, polluted and oxygen-deficient waters
  • Prefers sandy estuarine and marine habitats, can also colonise hard substrates


  • Can prey heavily on native shellfish and aquaculture species
  • Can affect bottom dwelling organisms

Similar native species

These native species may be confused with this marine pest.

Cartrut shell / Dicathais orbita

Cartrut shellKey features:

  • Shell sculptured with grooves
    White/grey/brown/green colour
    Shell height up to 7-8cm


  • Reef up to 10m depth

Helmet shell Semicassis pyrum

Helmet shellKey features:

  • Smooth shell
  • Cream with brown blotches
  • Shell height up to 7cm


  • Exposed sand up to 480m depth

What is NSW DPI doing?

On the 1st July the NSW Government implemented a new Biosecurity Act 2015 (the Act). Under Schedule 2 of this Act the Rapa or Veined Welk is declared as prohibited matter in NSW. This means it is illegal to possess, buy, sell or move this pest in NSW. Heavy penalties apply for non-compliance. In addition, NSW DPI has the power to seize and require the destruction of the pest.

People are expected to have a basic level of knowledge about the biosecurity risks they might encounter in their normal work and recreational activities. All community members have a general biosecurity duty to consider how actions, or in some cases lack of action could have a negative impact on another person, business enterprise, animal or the environment. We must then take all reasonable and practical measures to prevent or minimise the potential impact.

How can you help?

Learn to recognise, and be aware of, the rapa/veined whelk so that you can report any suspected sighting immediately.

  • Note the exact location
  • If possible take a photo and/or collect a sample
  • Freeze sample in a plastic bag
  • Report your sighting