Practical information to identify and manage non-native, invasive plants and animals
The Quiet Invasion:
A Guide to Invasive Species of the Galveston Bay Area
Veined rapa whelk
Rapana venosa

ITIS TSN:73236
Presence:Species of Concern
Habitat:Aquatic
Native Range:Western Pacific near China and Japan
Human Health
This species poses no known human health impacts.
Prohibited Lists
As of 2010, this species is not prohibited by the TPWD.
Introduction Pathways
The veined rapa whelk was introduced to the U.S. via ballast water, boat hull fouling and aquaculture. It is transported locally through natural dispersion of its egg mats (ISSG 2006h).
Geographic Distribution
Since its discovery in 1998, R. venosa has become established and widespread in the Chesapeake Bay. This species is not currently present in Texas or the Galveston Bay watershed (Richerson 2006a).
Specific Primary Habitats
The veined rapa whelk prefers sandy bottoms ideal for deep burrowing. This species tolerates a wide range of temperature (4-35°C) and salinity (7-32 ppt). This species is capable of migrating to warmer, deeper waters to avoid winter cooling of surface temperatures. This species also tolerates water pollution and low dissolved oxygen (ISSG 2006h).
Ecological, Economic, or Social Impact
R. venosa are known as voracious predators and have the capability of seriously affecting oyster, clam, and mussel populations. Whelks may also have significant impacts on benthic ecosystems (Richerson 2006a).
Physical Description
R. venosa is a large, predatory marine snail. Its shell can range from gray to reddish brown in color with dark brown, vein-like patterns along the smooth ridges of the shell. The shell spire is short, with a large body whorl. The veined rapa whelk is often identified by the characteristic dark orange color of its aperture. These snails can grow up to 15 cm long in the Chesapeake Bay (Richerson 2006a; VIMS 2009).
Reproduction Characteristics
Veined rapa whelks reproduce in water temperatures ranging from 13-26°C. They lay yellow egg masses of 50-500 egg cases, each containing 200-1000 eggs per case. There is a 14-21 day incubation period, after which larvae emerge and remain in the water column for up to 80 days before settling on the sea floor (ISSG 2006h).
Feeding
A generalist and voracious predator of mollusks such as clams, oysters, and mussels (VIMS 2009).
Control
Early detection is key to preventing the spread and establishment of this species and regional/local monitoring or surveillance is essential. Nonnative snails should not be released in local waterways. If found in local waters, note the location and notify the TPWD.

This species belongs to the following lists:
Images
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Veined rapa whelk <i>(Rapana venosa)</i>.  Photo courtesy of USGS, USGS NAS Database, http://nas.er.usgs.gov.
Veined rapa whelk (Rapana venosa).  Photo courtesy of USGS, USGS NAS Database, http://nas.er.usgs.gov.
Veined rapa whelk <i>(Rapana venosa)</i>.  Photo courtesy of USGS, USGS NAS Database, http://nas.er.usgs.gov.
Veined rapa whelk (Rapana venosa).  Photo courtesy of USGS, USGS NAS Database, http://nas.er.usgs.gov.
Egg mat of a veined rapa whelk <i>(Rapana venosa)</i>.  Photo courtesy of Juliana M. Harding, Virginia Institute of Marine Science, Bugwood.org.
Egg mat of a veined rapa whelk (Rapana venosa).  Photo courtesy of Juliana M. Harding, Virginia Institute of Marine Science, Bugwood.org.
Page Updated/Reviewed: 09/07/2010 10:20 AM
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