Egg-citing Finds!

whelk egg casing on beach

By Rebecca Ruger

So, you’re walking along the beach when you stumble across what looks to be the skeleton of an eel, or maybe even something as exciting as a marine species long thought extinct. It looks like a snake-shaped connected mass of bone or cartilage. What you have found is indeed a wonder of nature, but not too terribly uncommon. It is the egg casing of a whelk snail.

Whelk is a common name used to describe certain types of larger sea snails of the family Buccinidae, which are predatory marine mollusks with heavy, pointed spiral shells. The most common types of whelks found along the U.S. Atlantic coast and the Gulf of Mexico are knobbed, channel, lightning, and pear whelks.

types of living whelks in shells

Whelk eggs are fertilized internally and laid in capsule packets. Strings of these connected egg capsules are usually one to three feet in length, comprised of up to 160 capsules, each containing almost 100 eggs. The mother whelk anchors one end of the string onto rocks, shells, or sand on the sea floor for safety.

knobbed whelk egg casing with baby shells

The paper chain of egg cases is sometimes referred to as a Mermaid’s Necklace, but cute name aside, the beginnings of these marine mollusks is rough. Only one percent will hatch successfully, and often the first to hatch will eat their siblings. If they emerge successfully from the egg case, they are juvenile whelks of about 4mm in length, and can expect to live for about 10 to 15 years if they reach maturity.

Determining if a dead egg casing was from a knobbed, pearl, channeled, or lightning whelk is not very difficult. The knobbed whelk segmented sections resemble sliced discs and the channeled whelk sections are pillow-like in shape with a plump middle. Lightning whelk cases are distinguishable by their tiny bumped edges and the pear whelk casings have noticeable spikes.

Whelk egg casings are interesting to see and touch, but if there are eggs still inside the casing, immediately return the entire chain to the sea.

This article appeared in the Beachcombing Magazine March/April 2019 issue.

Learn more about seashells

nature and history of seashells and collecting

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No live shelling: Be sure shells are empty and sand dollars, sea stars, and sea urchins are no longer alive before you bring them home.

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