Weekly Sea Discovery: Whelks!
We’re feeling extra whelky here today at the Mayne Island Conservancy, so we’re featuring two different whelks: the Dire Whelk and the Frilled Dogwinkle! You can find these predatory marine snails in the intertidal surrounding Mayne Island by turning over rocks or sorting through seaweed at low tide. These intertidal snails can get up to 5 cm long, but they look quite different from each other.
Dire Whelks have horizontal striped ribs along their shell, while the Frilled Dogwinkle have unique vertical frills that can be more or less prominent depending on how much wave action they endure. Both snails can be a variety of colours, usually greyish to brown, but Frilled Dogwinkles can be vibrant colours like purple and orange!
Different feeding strategies are used by each snail. Frilled Dogwinkles are your classic predatory snail; they drill holes into their prey using a sharp tongue (radula) and proceed to reach in and ingest the organism (usually barnacles and mussels). But Dire Whelks prefer to scavenge for their prey, looking for injured or dead organisms like limpets, chitons and crabs. While these snails are feeding on other invertebrates in the intertidal, they have to watch out for things that might want to eat them, like crabs and sea stars.
One interesting adaptation of the Frilled Dogwinkle is they can increase their shell formation, particularly the frills, when they sense Red Rock Crabs in their environment. This makes it more difficult for the crabs to break in and eat them.