The veined rapa whelk is a large, heavy sea snail native to East Asia. In the US it has become established in the lower Chesapeake Bay, where it was first found in 1998 and is considered invasive because it eats oysters, clams, and mussels. The deep orange color inside the shell opening is the easiest clue; it is also called the Asian rapa whelk.
Appearance
- Appearance
- A heavy, rounded, boxy shell nearly as wide as it is long, with a very short spire and a large . Grows to about 6–7 in (15–18 cm). The outside is gray to reddish-brown with dark brown dashes on the spiral ridges, most shells have dark veins, and the opening is deep orange.
Look-alikes
The native knobbed whelk has an ivory or pale gray shell with a ring of knobs at the widest part of each coil and a lighter orange opening. The rapa whelk is gray to reddish-brown, boxy, with dark veins and a deeper orange opening.
Why they get mixed upBoth are large whelks with an orange shell opening found on the mid-Atlantic coast.
Where it lives
- Typical habitats
- Sandy bay bottoms
- Estuaries
- Shallow coastal water
- Range
- Native to the Sea of Japan, Yellow Sea, East China Sea, and Bohai Sea. In the US it is established in the lower Chesapeake Bay in Virginia, along the western shore from New Point Comfort to Cape Henry and in the James and York rivers. It also spread to the Black Sea in the 1940s and later to parts of the Mediterranean and South America.
- Preferred conditions
- Prefers firm sandy bottoms where it can bury itself almost completely. It tolerates big temperature swings, pollution, and low-oxygen water, and may move to deeper water in winter to avoid freezing surface water.
Behavior
- Diet
- Bivalves such as oysters, clams, and mussels. Instead of drilling through the shell like many snails, it wraps around the hinge of its prey and feeds between the opened shells.
Life cycle
- Reproduction
- In warmer months, females attach clusters of egg cases to rocks and other hard surfaces. Each case is about 2 in (5 cm) tall, and a cluster can look like a little patch of yellow shag carpet. Tiny free-swimming larvae hatch in about 18–26 days and settle to the bottom after 4–6 weeks.
- Time to maturity
- Grows fast in its first year and can reproduce by its second year.
- Lifespan
- Can live more than 10 years.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
- Threats
- Scientists worry it could harm native shellfish and the bay's seafood industry. In the Black Sea it has greatly changed bottom-dwelling communities.
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