Veined Rapa Whelk
 (Rapana venosa)
 

 
Whelk photo courtesy of: Virginia Institute of Marine Science
 
 
INTRODUCTION
Description
The Veined Rapa Whelk (Rapana venosa) is a member of the Muricidae, a family of predatory marine snails. They eat a variety of mollusks and they often attack bivalves (oysters, clams, mussels). Whelks may get to their prey by boring a hole into the edge of its shell or in the case of bivalves, by rasping around the region where the two valves meet and prying it open. They reproduce by laying egg clusters. Pelagic larvae hatch out of the eggs and sink to the bottom. Then they develop a hard shell. The Veined Rapa Whelk has a heavy short spired shell with a large inflated body whorl. The outer color is variable from gray to red brown, with dark brown dashes on the spiral ribs. Most specimens have distinctive black veins throughout the shell. A very characteristic feature of the species is the deep orange color found on the inside of the shell. Rapa whelks may grow to be quite large. The largest record in the literature for the native range is 18.3 cm shell length from Taiwan. A length of 12.1 cm has been published from the Black Sea. Several specimens in excess of 15 cm shell length have been collected from Hampton Roads, Virginia. They prefer sandy bottoms where they can burrow. The Rapa Whelk is very versatile. It will tolerate low salinities, polluted waters and oxygen deficient waters. 

Sources from USGS http://www.fcsc.usgs.gov/Nonindigenous_Species/Rapana.pdf and Molluscan Ecology Program, Virginia Institute of Marine Science http://www.vims.edu/mollusc/research/merapven.htm
 

Impacts
Veined Rapa Whelks have caused changes in populations of bottom dwelling organisms, and have become marine pests in the Black Sea. Research is still being conducted to determine the impacts of these whelks on native species and their ecosystems. 

Source from USGS http://www.fcsc.usgs.gov/Nonindigenous_Species/Rapana.pdf
GEOGRAPHICAL INFORMATION
Origin
Rapa whelks are native to the Sea of Japan. The Veined Rapa Whelk is restricted to the Yellow Sea, the East China Sea and the Bohai Sea. This is a region of wide annual temperature ranges, comparable to that of the Chesapeake Bay. In winter populations may migrate from estuarine waters into deeper water (possibly to avoid freezing surface water).  This species was introduced into the Black Sea in the 1940s, and later spread to the Aegean and Adriatic seas. Now Rapa Whelks are also located in the Chesapeake Bay area. Scientists believe whelk larvae were transported to different locations in ship ballast water.

Sources from Molluscan Ecology Program, Virginia Institute of Marine Science http://www.vims.edu/mollusc/research/merapven.htm and Bay Journal Volume 9 Number2 April 1999 http://www.bayjournal.com/99-04/WHELK.HTM
DISTRIBUTION
Links to Rapa Whelk’s Distribution Maps
http://www.vims.edu/mollusc/research/rapaw/merapmap.htm (The current distribution of Rapa Whelks in Chesapeake Bay)
http://www.vims.edu/mollusc/research/rapaw/mervintro.htm (Home range of the rapa whelk)

 
CONTROL METHODS
Control 
Currently as a form of control, there is a bounty being paid for Rapa Whelks in the United Sates. A bounty of $5 per snail will be paid for LIVE Rapa Whelks. A bounty of $2 per snail will be paid for DEAD Rapa Whelks or empty Rapa Whelk shells. 

Source from Molluscan Ecology Program, Virginia Institute of Marine Science http://www.vims.edu/mollusc/research/rapaw/mervbounty.htm

 
USEFUL PICTURE COLLECTIONS 

 
Credit: ?
Org: Virginia Institute of Marine Science (A rapa whelk eating a hard clam.)		 Credit: ?
Org: Virginia Institute of Marine Science (Rapa whelk egg cases)
Credit: Roger Mann
Org: Virginia Institute of Marine Science (Rogue Rapa whelk’s shell)		 Credit: ?
Org: The Audubon Society Field Guide to North American Seashells (Common Northern Whelk)
Credit: Roger Mann
Org: Virginia Institute of Marine Science (Rapa whelk’s shell)
RELATED SITES
Virginia Institute of Marine Science> http://www.vims.edu/mollusc/research/merapven.htm 
General information on whelks and the School of Marine Science’s research. 

Veined Rapa Whelk: Chesapeake Bay Program> http://www.chesapeakebay.net/info/rapa.cfm
General Information about the Rapa Whelk

Invasive Species: Veined Rapa Whelk profile> http://www.invasivespecies.gov/profiles/rapawhelk.shtml
This site is a link to many other sites about the whelk. 

Maryland Recreational Fisheries> http://www.dnr.state.md.us/fisheries/recreational/articles/3exoticspp.html
This site provides three exotic species have been detected and identified in Maryland's coastal waters and in the lower Chesapeake: the European green crab, the
Japanese shore crab, and the veined rapa whelk.

 
EDUCATIONAL RESOURCES
Lesson Plans & Activities 
Educational activities may be found at > http://www.iiseagrant.org/EXOTICSP/

REFERENCES
Virginia Institute of Marine Science> http://www.vims.edu/mollusc/research/merapven.htm 
General information on whelks and the School of Marine Science’s research.

USGS> http://www.fcsc.usgs.gov/Nonindigenous_Species/Rapana.pdf
General information bulletin on the Rapa Whelk

The Chesapeake Bay Newspaper>http://www.bayjournal.com/99-04/WHELK.HTM
An article about the veined Rapa Whelk
Compiled by Laura Muskopf