Its low tide and you find yourself strolling down one of Georgia's beaches, enjoying a favorite pastime of combing the sand in search of a seashell. Near the waters edge your eyes catch a glimpse of a beautiful shell with knobby spikes. As you lean down to pick up your newfound prize, closer inspection reveals a large snail-like critter apparently residing inside the shell. It appears what you have found is a Knobbed Whelk (Busycon carica)∨ is it? 

Scientists conducting studies in the Chesapeake Bay area have recently discovered a non-native whelk species, the Veined Rapa Whelk (Rapana venosa). Unlike the native Knobbed Whelk commonly found in Georgia's waters, the Veined Rapa Whelk is an introduced species native to the Sea of Japan. It arrived in Chesapeake Bay as planktonic larvae via ballast water from trans-oceanic ships entering local ports. Although there have been no confirmed reports of Veined Rapa Whelk in Georgia, the potential exists with international ports in both Savannah and Brunswick. As with any non-native species, the concern is over its impact to local species. When introduced to the Mediterranean region in the 1940s, the Rapa quickly decimated several shellfish (oysters, clams, etc) populations.

But how would one tell the difference between the native Knobbed Whelk and the exotic Veined Rapa Whelk? The Knobbed Whelk is more elongated in shape than the Veined rapa whelk. Both are right shelled, meaning they open to the right, but the Rapa Whelk opening is an extreme bright orange in color, with black veins running along the exterior of the shell. In the picture below, compare the native Knobbed Whelk on the left to the foreign Veined Rapa Whelk on the right.

The life cycles of both species also appear to be similar. Eggs are laid in protective egg capsules joined to form an egg case. However, the shape of the egg case differs for each. Knobbed Whelk egg cases often have a string-like appearance (commonly known as mermaids necklace) while Veined Rapa Whelk egg cases have a mat-like appearance, resembling yellow shag carpet. In the picture below, the Knobbed Whelk egg case is on the left, the Veined Rapa Whelk egg case is on the right.

Though many similarities exist between these species, one significant difference remains vitally important:  one species is native and the other is not. As with any non-native species, many questions remain concerning the effects of the Veined Rapa Whelk on native marine mollusk populations. Increased public awareness and reporting of potential sightings are both critical and necessary for protecting our coast.

If you find a Veined Rapa Whelk on a Georgia beach or in Georgia waters, please call the DNR Coastal Resources Division in Brunswick at 912-264-7218, or contact any DNR office.