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The scallop, an animal that goes back in time

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It is at the heart of the fishing conflict between France and the United Kingdom, it is also at the center of the plates of the end of the year celebrations … The scallop is a mollusk that contains many secrets. Thousands of pieces of information are stored by this “sentinel of the sea”.

“When I say scallop, you see a festive dish. Laurent Chauvaud is the French specialist in scallops, not in the kitchen, but in the sciences. And it is science that teaches us a lot about one of the most consumed seashells during the holiday season. Yes, first of all, why do we love him so much?

So what is the secret of its taste? “We humans store glycogen, sugar, in your liver, explains Jacques Chauvaud, oceanographer at the CNRS. The scallop does that in its muscle. So when you put butter in a pan with a scallop, and heat it up, the taste you get is a taste of sugar. Here is an animal whose biology is favorable to us! “And that’s why pan-fried scallops take on a slightly brownish appearance: they caramelize …

One day, a streak

This highly sought-after dish has become an object of research. In every shell, the skeleton that protects this tasty muscle, there is tons of information that science can now decipher. The scallop is an animal to go back in time, an environmental archive, a “Sentinel of the sea”, to use the title of one of Laurent Chauvaud’s works, who discovered it (Équateurs editions). Every streak that the animal makes every day would be like an old parchment that an archaeologist could decipher.

“Try to imagine hieroglyphs that provide information first on the properties and state of health of the scallop, then on its environment: temperature, salinity, presence of toxic algae, oxygen concentration. .. This animal has archived information in its skeleton, on a daily scale, for the duration of its life. It is thus possible to calculate the sea water temperature every day. And even 25 million years ago if you will ” , since scallops have been present on the planet for 25 million years. The chemical information gathered by this bivalve mollusk is so precise that the water temperature can be determined to within 0.2 degrees Celsius.

The taste of coral

The European scallop, Pecten maximus (the real one, say the purists), lives off the Normandy and Breton coasts and finds herself, despite herself, at the heart of the fishing dispute between France and the United Kingdom since Brexit. A species that is not threatened, due to reasoned fishing. The scallop has nearly 200 eyes. It moves by closing its valve, and the jet of water that shoots throws it back at such a speed that it can escape predators.

Finally, the Saint-Jacques is hermaphrodite; she has both male and female sexual organs. “The trick is to emit the male gametes first, never in synchronous ways with the female gametes, to avoid self-fertilization,” specifies Laurent Chauvaud. And it works very well: the scallops emit a few million eggs after having emitted a few billion sperm. “The sexual organs are found in the coral, male in the white part, female in the orange part. Coral, the most sought-after piece of the scallop by gourmets.

“What do a shell and a tree have in common? “

These are the rings, or the streaks, the growth rings, which make it possible to measure their age, on a trunk cut for the tree or on the shell, of the Saint-Jacques for example. One line per year is easy to count. On a meadow, a small mollusk fished in the North Atlantic, we were able to count 507. Which makes it 507 years old, and which makes it the oldest animal in the world. But beware, only the solitary animal, because the corals, which live in colonies, can reach several tens of thousands of years.


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