Dora
RebeccaWhile diving in the sea this winter, divers once again noticed fan-shaped clams growing from the sea floor.
These are fan mussels, also known as noble pen shells, an endemic of the Mediterranean Sea.
They can live up to sixty meters deep. They are an important part of the marine ecosystem because their huge shell provides shelter for many organisms long after the shell is no longer alive.
Fan mussels are a protected species, so they must not be collected.
In the 1980s they were listed as an endangered species, which was probably the result of human activities such as fishing, the use of trawling nets, anchoring, and collecting shells for decoration.
Dr. Domen Trkov, Marine Biological Station Piran
“The fan mussel populations recovered, but then in 2016 biologists noticed that in the Mediterranean Sea they started to disappear in masses.”
At that time in the Adriatic Sea, most of the adult fan mussels died.
The death was most likely caused by protozoa or pathogenic bacteria.
Recently, however, young specimens are appearing again, inhabiting the vacated environment. It is difficult to say what the reason for the resettlement is because we don’t know the exact cause of death yet.
Dr. Domen Trkov
“However, the fact is that the young specimens, which are the descendants of the surviving adult shells, returned to the seabed from the planktonic larvae.”
The divers do not want to reveal where they were all found, reports Boris Šuligoj in Delo.
Glossary
A population is a larger group of individuals, usually of the same species, living in the same place.
An endemic is an organism that lives only in a certain part of the world.
Protozoa are unicellular organisms that cannot be classified as animals, plants or bacteria. Most of them are microscopic, some of them cause diseases.
Points to Consider
- Have you ever seen a fan mussel?
- Do you know of any other endemics?
- What is plankton?
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The original version of this article was published on 24th January.
Romana
Mateja
