In the summer, many people consider it their duty to go to the sea. You want to keep memories of warm days and vacations for a long time, so tourists often take shells with them as souvenirs. It would seem that nothing bad should happen from a couple of shells taken home. But scientists and authorities in some countries react very sharply to this – some tourists even receive prison sentences and large fines simply for taking mollusk shells. In fact, with this seemingly harmless action, thousands of tourists every year cause enormous harm to wildlife. We invite you to briefly understand why there are often a lot of shells on the beaches, and also why tourists are sometimes punished for collecting them.
In some countries, you can get jail time for collecting shells on the beach. Image source: readingrockets.org
Where do seashells come from on beaches
Shells on beaches appear thanks to mollusks that live in the seas and oceans. Science knows the existence of approximately 200 thousand soft-bodied creatures that create shells from calcium contained in the environment. Clam shells expand as they grow and calcium is deposited on them layer by layer.
Mollusks grow shells for several purposes. First, the shell protects them from predators and physical harm. Secondly, the shell serves as a strong frame to support the soft tissues of the mollusk. Thirdly, the hard shell helps the mollusks retain moisture and prevent the body from drying out.
Sea clam with shell. Photo source: bangkokbook.ru
When clams die, their soft tissues decompose or become food for other aquatic organisms. Then many of them end up on the shore because strong waves throw them there. Sometimes shellfish shells break into pieces, which is why you can find damaged shells on beaches. Usually, tourists take whole specimens with them as souvenirs, and they are the ones that bring the greatest benefit to nature.
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Why do animals need shells?
Clams grow shells for protection, but why do other animals on land need them?
According to IFL Science, clam shells scattered along the beach are used by birds to build strong nests. Also, some species of birds swallow fragments of shells in order to crush food in the stomach and thereby speed up digestion.
Hermit crabs use washed-up mollusk shells as homes. These crustaceans have a soft and vulnerable abdomen that is not covered with a hard shell like other crab species. Therefore, they need additional protection, which they find in the empty shells of sea mollusks. As they grow, hermit crabs can exchange shells for larger ones.
A hermit crab inside a found shell. Image source: vmnews.ru
Some marine organisms use empty shells as incubators for their eggs, providing additional protection for their offspring in a resourceful manner. For example, sea snails, crayfish and lobsters lay their eggs in empty shells. Once born, the offspring can use the shells for protection until they are ready to emerge.
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In which countries you cannot collect shells
In 2014, scientists estimated by what percentage the number of shells in one of the beaches in Spain had decreased. It turned out that from 1978 to 2010, the number of sea shells there decreased by a frightening 60%. This means that dozens, and maybe hundreds of species of animals were left without building materials, incubators for eggs and housing. In the long term, this may lead to a reduction in their numbers.
In some countries, authorities are cracking down on those who collect shells. For example, in Great Britain, since 1949, there has been a law prohibiting the taking of anything of natural origin from beaches.
In the absence of real shells, hermit crabs begin to use garbage. Photo source: fishki.net
In the USA, collecting empty shells is allowed, but some types of shellfish are strictly protected, and unknowingly tourists can get into big trouble. In 2018, a woman was detained in the US state of Florida for taking 40 shells from a Key West beach. It turned out that they belonged to an endangered species, so she was detained for 15 days and forced to pay a fine of $500.
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