Veined rapa whelk
Encyclopedia
Rapana venosa, common name the veined rapa whelk or Asian rapa whelk, is a species
of large predatory sea snail
, a marine
gastropod mollusk or whelk
, in the family Muricidae
, the rock shells.
This large sea snail has become an invasive species in many different localities around the world.
of Rapana venosa is globose (rounded) and heavy, possessing a very short spire
, a large body whorl
, a strong columella and a deep umbilicus. The apeture
is large and roughly ovate. Ornamentation is present externally as axial ribs
, smooth spiral ribs
ending in blunt knobs at both the shoulder and body whorl, and internally as small elongated teeth disposed along the outer lip margin. The external color varies from gray to reddish-brown, with dark brown dashes on the spiral ribs. Some specimens may have distinctive black/dark blue vein-like coloration patterns throughout the inner portions of the shell, usually originating from each individual teeth at the outer lip.
A diagnostic feature for this species is the deep orange color found in the aperture
and on the columella. The height of the shell can reach up to 180 mm (about 7 in).
, Yellow Sea
, East China Sea
and the Bohai Sea
.
Rapana venosa, is included in Russia
's Red Book
as threatened with extinction. The original known habitat for this species was the Far East
, but in 1947 it was found in the Black Sea
, and its shell became a popular souvenir traded in the Crimea
. Recently this species has been found as an exotic in the Chesapeake Bay
, on the eastern coast of the USA.
Nonindigenous distribution
According to some authors, it appears to be the case that the spreading of this species outside its natural range has been made possible by the planktonic larval stage being transported along with ballast water in the hulls of ships, or that egg masses may have been transported with products of marine farming.
Rapa whelks were first found in the Black Sea
in the 1940s. Within a decade this mollusk had spread along the Caucasian
and Crimea
n coasts and moved into the Sea of Azov
. From 1959 to 1972, its range extended into the northwest Black Sea, to the coastlines of Romania
, Bulgaria
and Turkey
. Those whelks have become established in the Adriatic
and Aegean
sea, and have also been found in the Tyrrhenian sea
, the Northern Atlantic coast of France
, and the southeast coast of South America
, in Uruguay
and Rio de La Plata
estuary (including Samborombon Bay
), in Argentina
. In the United States
the first specimen discovered was in August 1998 by members of the Virginia Institute of Marine Science (VIMS) Trawl Survey Group in Hampton Roads
, Virginia
. The species is now widely distributed and established in Chesapeake Bay
.
Rapana venosa is considered among 100 worst alien
species in Europe in DAISIE European Invasive Alien Species Gateway, one of two marine gastropods on the list.
and oxygen deficient
waters.
s (Crassostrea virginica) and mussel
s (Mytilus galloprovincialis, Modiolus
and Geukensia
), but also clams (Anadara inaequivalvis, Chamelea gallina
, Tapes philippinarum, Venus verrucosa, and the northern quahog Mercenaria mercenaria). Prey are chosen by the whelk according to their species and size. Most snails feed by drilling a hole into their bivalve prey, but rapa whelks usually smother their prey by wrapping around the hinged region of the shell and feed by introducing its proboscis
between the opened valves. The whelk can also secrete a thick mucus
that may or may not contain biotoxins to weaken the prey. Shell drilling, however, is not an unregistered event in this species.
, which means each individual organism belonging to this species is distinctly male or female. In this species native range, mating occurs for extended periods of time, mainly during the winter and spring. It reproduces by internal fertilization
, after which it lays clusters of egg cases that resemble small mats of white to yellow shag carpet, mainly during spring and summer. One adult female individual can lay multiple egg cases throughout the season. Each cluster contains 50-500 egg cases, and each egg case may contain 200-1000 eggs. The pelagic veliger
larvae (a larval form common to various marine and fresh-water gastropod and bivalve mollusks) then hatch, persisting in the water column for 14 to of 80 days and feeding primarily on plankton
. They eventually settle on the ocean floor where they develop into hard-shelled snails. Growth is rapid over the first year of life, and reproduction occurs from the second year onwards. Large specimens may be over ten years old.
The Veined rapa whelk is also highly tolerant to wide variations in salinity and oxygen concentration, a fact that may also help to explain its success as an invader of marine coastal and brackish
ecosystems. In its native range Rapana venosa shows high temperature tolerance, being able to withstand temperatures varying from 4 to 27 °C (39.2 - 80.6 °F).
of bottom-dwelling organisms, and have become marine pests in the Black Sea. Although scientists are not completely aware of the impacts of the whelk, they are very concerned about its potential impact on native Bay species. Studies are currently under way to help determine the whelk's spread in the Chesapeake Bay, so that scientists can develop a model that will define potential impacts to the Bay's ecosystem.
phenomenon has been observed in the veined rapa whelk in Chakespeare Bay. Imposex is characterized by the development of masculine sexual organs in female individuals as a consequence of exposure to organic tin compounds, such as tributyltin
(TBT). Such compounds are biocide and antifouling agents, commonly mixed in paints to prevent marine encrustations on boats and ships. For this reason, it is not uncommon for high concentrations of such compounds to be present in the sea water near shipyards and dock
ing areas, consequently exposing the nearby marine life to its possibly harmful effects. This unnatural development of male reproductive organs, however, has shown no negative effects on populations of this species, and no loss of reproductive capabilities of female R. venosa as a consequence of Imposex has been observed so far.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of large predatory sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
, a marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
gastropod mollusk or whelk
Whelk
Whelk, also spelled welk or even "wilks", is a common name used to mean one or more kinds of sea snail. The species, genera and families referred to using this common name vary a great deal from one geographic area to another...
, in the family Muricidae
Muricidae
Muricidae, common name murex snails or rock snails, is a large and varied taxonomic family of small to large predatory sea snails. With approximately 1,600 living species the Muricidae represent almost 10% of the Neogastropoda. Additionally, 1,200 fossil species have been recognised...
, the rock shells.
This large sea snail has become an invasive species in many different localities around the world.
Shell description
The shellGastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
of Rapana venosa is globose (rounded) and heavy, possessing a very short spire
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...
, a large body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
, a strong columella and a deep umbilicus. The apeture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
is large and roughly ovate. Ornamentation is present externally as axial ribs
Sculpture (mollusc)
The sculpture of a mollusc shell is the three-dimensional ornamentation on the outer surface, as distinct from the basic shape of the shell itself or colouration. Sculpture may be concave as well as convex. Sometimes it has microscopic detail. Sculpture refers to the calcareous outer layer, not the...
, smooth spiral ribs
Sculpture (mollusc)
The sculpture of a mollusc shell is the three-dimensional ornamentation on the outer surface, as distinct from the basic shape of the shell itself or colouration. Sculpture may be concave as well as convex. Sometimes it has microscopic detail. Sculpture refers to the calcareous outer layer, not the...
ending in blunt knobs at both the shoulder and body whorl, and internally as small elongated teeth disposed along the outer lip margin. The external color varies from gray to reddish-brown, with dark brown dashes on the spiral ribs. Some specimens may have distinctive black/dark blue vein-like coloration patterns throughout the inner portions of the shell, usually originating from each individual teeth at the outer lip.
A diagnostic feature for this species is the deep orange color found in the aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
and on the columella. The height of the shell can reach up to 180 mm (about 7 in).
Distribution
This species is native to the marine and estuarine waters of the western Pacific, from the Sea of JapanSea of Japan
The Sea of Japan is a marginal sea of the western Pacific Ocean, between the Asian mainland, the Japanese archipelago and Sakhalin. It is bordered by Japan, North Korea, Russia and South Korea. Like the Mediterranean Sea, it has almost no tides due to its nearly complete enclosure from the Pacific...
, Yellow Sea
Yellow Sea
The Yellow Sea is the name given to the northern part of the East China Sea, which is a marginal sea of the Pacific Ocean. It is located between mainland China and the Korean Peninsula. Its name comes from the sand particles from Gobi Desert sand storms that turn the surface of the water golden...
, East China Sea
East China Sea
The East China Sea is a marginal sea east of China. It is a part of the Pacific Ocean and covers an area of 1,249,000 km² or 750,000 square miles.-Geography:...
and the Bohai Sea
Bohai Sea
Bohai Sea , also known as Bohai Gulf, Bohai, or Bo Hai, is the innermost gulf of the Yellow Sea on the coast of Northeastern and North China. It is approximately 78,000 km2 Bohai Sea , also known as Bohai Gulf, Bohai, or Bo Hai, is the innermost gulf of the Yellow Sea on the coast of...
.
Rapana venosa, is included in Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
's Red Book
Red Data Book of the Russian Federation
Red Data Book of the Russian Federation , also known as Red Book or Russian Red Data Book is a state document established for documenting rare and endangered species of animals, plants and fungi, as well as some local subspecies that exist within the territory of the Russian Federation and its...
as threatened with extinction. The original known habitat for this species was the Far East
Far East
The Far East is an English term mostly describing East Asia and Southeast Asia, with South Asia sometimes also included for economic and cultural reasons.The term came into use in European geopolitical discourse in the 19th century,...
, but in 1947 it was found in the Black Sea
Black Sea
The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
, and its shell became a popular souvenir traded in the Crimea
Crimea
Crimea , or the Autonomous Republic of Crimea , is a sub-national unit, an autonomous republic, of Ukraine. It is located on the northern coast of the Black Sea, occupying a peninsula of the same name...
. Recently this species has been found as an exotic in the Chesapeake Bay
Chesapeake Bay
The Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West...
, on the eastern coast of the USA.
Nonindigenous distribution
According to some authors, it appears to be the case that the spreading of this species outside its natural range has been made possible by the planktonic larval stage being transported along with ballast water in the hulls of ships, or that egg masses may have been transported with products of marine farming.
Rapa whelks were first found in the Black Sea
Black Sea
The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
in the 1940s. Within a decade this mollusk had spread along the Caucasian
Caucasus
The Caucasus, also Caucas or Caucasia , is a geopolitical region at the border of Europe and Asia, and situated between the Black and the Caspian sea...
and Crimea
Crimea
Crimea , or the Autonomous Republic of Crimea , is a sub-national unit, an autonomous republic, of Ukraine. It is located on the northern coast of the Black Sea, occupying a peninsula of the same name...
n coasts and moved into the Sea of Azov
Sea of Azov
The Sea of Azov , known in Classical Antiquity as Lake Maeotis, is a sea on the south of Eastern Europe. It is linked by the narrow Strait of Kerch to the Black Sea to the south and is bounded on the north by Ukraine mainland, on the east by Russia, and on the west by the Ukraine's Crimean...
. From 1959 to 1972, its range extended into the northwest Black Sea, to the coastlines of Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
, Bulgaria
Bulgaria
Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...
and Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
. Those whelks have become established in the Adriatic
Adriatic Sea
The Adriatic Sea is a body of water separating the Italian Peninsula from the Balkan peninsula, and the system of the Apennine Mountains from that of the Dinaric Alps and adjacent ranges...
and Aegean
Aegean Sea
The Aegean Sea[p] is an elongated embayment of the Mediterranean Sea located between the southern Balkan and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosporus...
sea, and have also been found in the Tyrrhenian sea
Tyrrhenian Sea
The Tyrrhenian Sea is part of the Mediterranean Sea off the western coast of Italy.-Geography:The sea is bounded by Corsica and Sardinia , Tuscany, Lazio, Campania, Basilicata and Calabria and Sicily ....
, the Northern Atlantic coast of France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, and the southeast coast of South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, in Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
and Rio de La Plata
Río de la Plata
The Río de la Plata —sometimes rendered River Plate in British English and the Commonwealth, and occasionally rendered [La] Plata River in other English-speaking countries—is the river and estuary formed by the confluence of the Uruguay River and the Paraná River on the border between Argentina and...
estuary (including Samborombon Bay
Samborombón Bay
Samborombón Bay is a bay of Argentina, located at the Río de la Plata's mouth on the Atlantic Ocean. It is about southeast of Buenos Aires. The bay is about long and stretches from Point Piedras in the north to Point Norte, starting point of Cape San Antonio.The bay receives the Salado and...
), in Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
the first specimen discovered was in August 1998 by members of the Virginia Institute of Marine Science (VIMS) Trawl Survey Group in Hampton Roads
Hampton Roads
Hampton Roads is the name for both a body of water and the Norfolk–Virginia Beach metropolitan area which surrounds it in southeastern Virginia, United States...
, Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
. The species is now widely distributed and established in Chesapeake Bay
Chesapeake Bay
The Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West...
.
Rapana venosa is considered among 100 worst alien
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
species in Europe in DAISIE European Invasive Alien Species Gateway, one of two marine gastropods on the list.
Habitat
Veined rapa whelks favor compact sandy bottoms, in which they can burrow almost completely. The native habitat of this species is a region of wide annual temperature ranges, comparable to other localities. Fleeing cold waters in the winter, this species may migrate to warmer, deeper waters, thereby evading cool surface waters. This fertile sea snail is extremely versatile, tolerating low salinities, water pollutionWater pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
and oxygen deficient
Oxygen saturation
Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...
waters.
Feeding habits
Veined rapa whelks are carnivorous selective predatory gastropods whose main diet consists of a variety of other mollusk species, mainly epifaunal bivalves such as oysterOyster
The word oyster is used as a common name for a number of distinct groups of bivalve molluscs which live in marine or brackish habitats. The valves are highly calcified....
s (Crassostrea virginica) and mussel
Mussel
The common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.The...
s (Mytilus galloprovincialis, Modiolus
Modiolus (genus)
Modiolus, the horsemussels, are a genus of medium-sized marine bivalve molluscs in the family Mytilidae.-Species:Species within the genus Modiolus include:* Modiolus adriaticus...
and Geukensia
Geukensia
Geukensia is a genus of marine bivalve mollusc in the Mytilidae family.-Species:Species within the genus Geukensia include:* Geukensia demissa Dilwyn, 1817 - Ribbed Mussel...
), but also clams (Anadara inaequivalvis, Chamelea gallina
Chamelea gallina
Chamelea gallina is a species of small saltwater clam, a marine bivalve mollusc in the family Veneridae, the venus clams.-Taxonomy:Linnaeus originally described Venus gallina from the Mediterranean in 1758. Other zoologists may have consequently assumed that Da Costa's 1778 Pectunculus striatulus...
, Tapes philippinarum, Venus verrucosa, and the northern quahog Mercenaria mercenaria). Prey are chosen by the whelk according to their species and size. Most snails feed by drilling a hole into their bivalve prey, but rapa whelks usually smother their prey by wrapping around the hinged region of the shell and feed by introducing its proboscis
Proboscis
A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...
between the opened valves. The whelk can also secrete a thick mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
that may or may not contain biotoxins to weaken the prey. Shell drilling, however, is not an unregistered event in this species.
Life cycle
Rapana venosa is dioeciousDioecious
Dioecy is the property of a group of biological organisms that have males and females, but not members that have organs of both sexes at the same time. I.e., those whose individual members can usually produce only one type of gamete; each individual organism is thus distinctly female or male...
, which means each individual organism belonging to this species is distinctly male or female. In this species native range, mating occurs for extended periods of time, mainly during the winter and spring. It reproduces by internal fertilization
Internal fertilization
In mammals, internal fertilization is done through copulation, which involves the insertion of the penis into the vagina. Some other higher vertebrate animals reproduce internally, but their fertilization is cloacal.The union of spermatozoa of the parent organism. At some point, the growing egg or...
, after which it lays clusters of egg cases that resemble small mats of white to yellow shag carpet, mainly during spring and summer. One adult female individual can lay multiple egg cases throughout the season. Each cluster contains 50-500 egg cases, and each egg case may contain 200-1000 eggs. The pelagic veliger
Veliger
A veliger is the planktonic larva of many kinds of marine and freshwater gastropod molluscs, as well as most bivalve mollusks.- Description :...
larvae (a larval form common to various marine and fresh-water gastropod and bivalve mollusks) then hatch, persisting in the water column for 14 to of 80 days and feeding primarily on plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
. They eventually settle on the ocean floor where they develop into hard-shelled snails. Growth is rapid over the first year of life, and reproduction occurs from the second year onwards. Large specimens may be over ten years old.
Reasons for the survival of this invasive species
It is known that the abundance of prey, the lack of competition from other gastropod species, as well as the absence of direct predators of R. venosa may be some of the factors that contributed to the successful establishment of new populations of this sea snail outside its native range. The thick strong shell of the rapa whelk is arguably its strongest advantage over native whelks, because rapas can easily prey on local whelks, whereas local whelks are unable to successfully attack rapas. The thick shell also means that predators such as sea turtles are unable to feed on the invasive species, and can only feed on local whelk populations. It is suggested that once the rapa whelk reaches adulthood, it exists unchecked in the local population, and can consume and reproduce freely.The Veined rapa whelk is also highly tolerant to wide variations in salinity and oxygen concentration, a fact that may also help to explain its success as an invader of marine coastal and brackish
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
ecosystems. In its native range Rapana venosa shows high temperature tolerance, being able to withstand temperatures varying from 4 to 27 °C (39.2 - 80.6 °F).
Impact of introduction
Veined rapa whelks have caused significant changes in the ecologyEcology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
of bottom-dwelling organisms, and have become marine pests in the Black Sea. Although scientists are not completely aware of the impacts of the whelk, they are very concerned about its potential impact on native Bay species. Studies are currently under way to help determine the whelk's spread in the Chesapeake Bay, so that scientists can develop a model that will define potential impacts to the Bay's ecosystem.
Imposex
The imposexImposex
Imposex is a descriptive term applied to some sea snails, marine gastropod molluscs which, under the toxic effects of pollutants, develop sex organs that are in contrast to their actual sex...
phenomenon has been observed in the veined rapa whelk in Chakespeare Bay. Imposex is characterized by the development of masculine sexual organs in female individuals as a consequence of exposure to organic tin compounds, such as tributyltin
Tributyltin
Tributyltin compounds are a group of compounds containing the 3Sn moiety, such as tributyltin hydride or tributyltin oxide. They are the main active ingredients in certain biocides used to control a broad spectrum of organisms...
(TBT). Such compounds are biocide and antifouling agents, commonly mixed in paints to prevent marine encrustations on boats and ships. For this reason, it is not uncommon for high concentrations of such compounds to be present in the sea water near shipyards and dock
Dock
-In transportation:*Dock , a structure for handling ships**Drydock, a basin that can be flooded and drained to allow a load to come to rest on a dry platform**Ferry slip, a docking facility that receives a ferryboat...
ing areas, consequently exposing the nearby marine life to its possibly harmful effects. This unnatural development of male reproductive organs, however, has shown no negative effects on populations of this species, and no loss of reproductive capabilities of female R. venosa as a consequence of Imposex has been observed so far.
Further reading
- Mann M. & Harding J. M. (2000). "Invasion of the North American Atlantic Coast by a Large Predatory Asian Mollusc". Biological Invasions 2(1): 7-22. doi:10.1023/A:1010038325620 Bondarev I. P. (2010). "Морфогенез раковины и внутривидовая дифференциация рапаны Rapana venosa (Valenciennes, 1846). [The shell morphogenesis and intraspecific differentiation of Rapana venosa (Valenciennes, 1846)]". Ruthenica 20(2): 69-90. PDF
External links
- Rapana venosa at Global Invasive Species Database
- Molluscan Ecology Program focused on Rapana venosa
- Bibliographic database about Rapana venosa
- photo of eggs
- Russian Red Book - Rapana thomasiana
- Species Profile- Veined Rapa Whelk (Rapana venosa), National Invasive Species Information Center, United States National Agricultural LibraryUnited States National Agricultural LibraryThe United States National Agricultural Library is one of the world's largest agricultural research libraries, and serves as a National Library of the United States and as the library of the United States Department of Agriculture...
. Lists general information and resources for Veined Rapa Whelk.