Patrici Bultó: "There are sharks that are 400 years old"

Patrici Bultó, a marine biologist, has retired in 2025 after 30 years at the Aquarium, where he worked as technical director and director of biology. "I love sharks," he says. And it shows in the passion with which he speaks not only about sharks, but about the entire seabed. Although he is concerned about the impact of climate change, he remains hopeful about humanity. "Good things have been done, like banning the killing and eating of sharks. If this has been done, it means other things can be done."

If the Mediterranean were a fish...

— For me it's not a fish, it's a plant: posidonia.

What is the best thing about the sea?

— It's where life begins; we come from the sea. Three-quarters of the planet is sea. We call ourselves planet Earth, but it would make sense to call ourselves planet Sea: the sea occupies more than 70% of the surface.

How many species live?

— We know about 200,000, but it's estimated there may be as many as 20 million. We know more about the surface of the moon than the bottom of the sea.

Anything negative about the sea?

— Human activity in recent years. It seemed like a dumping ground that could hold anything. But no. We have five islands larger than Spain that accumulate plastic. And the disappearance of species, like sharks, is very negative. Not only because of the climate emergency, but because for many years in Asian countries they were killed to make the famous shark fin soup.

Why are they important?

— They're at the top of the food chain. If sharks don't eat certain species, those species grow uncontrollably. And the food chain collapses. I love them, the sharks.

Really?

— They've been largely unknown and treated very unfairly. They've long been considered vipers. I like many things about them. They can swim while they sleep; it's incredible. They automate swimming, just like we do with breathing at night.

Can I encounter any dangerous sharks in the Mediterranean?

— Humans are not part of any shark's diet; that's the first thing that needs to be made clear. How many people have been killed by sharks in Spain? None. They only attacked humans when they made a mistake, because, looking from below, they mistook a surfer for a sea lion or a seal.

What animal should scare us?

— If we're talking about the Mediterranean, jellyfish. They won't kill us, but some have a very painful sting. And the sea viper, which burrows under the sand, and if you're walking and step on its dorsal fin, it injects venom. You don't die, but it's tough.

What is the smallest fish?

— The candiru, which lives in the waters of the Amazon River and burrows into the urinary tract. It enters where you pee. Some people have had to have their genitals cut off. But we probably haven't discovered the smallest one yet, because it's so small it's probably in the sand.

Of sharks, which ones are the small ones?

— In the Mediterranean, the smallest shark is the negrito, measuring about 20 centimeters.

And what lives longer?

— The northern shark. It can live more than 400 years. Do you know what this means? Some sharks that swim in the Arctic today were already alive when Cervantes wrote Don Quixote.

Wow!

— They reach sexual maturity at 100 years of age.

Generally, when can fish reproduce?

— The most familiar ones, sea bream and sea bass, can reproduce from their second year onwards. But many fish are hermaphrodites, undergoing a sex change.

Are they male and female?

— The sea bream, for example, has both male and female organs. When it's young, it's male, and when it's older, it acts like a female. And the sea bream is the other way around. When it's young, it's female, and when it's older, it's male. It all depends on the balance of the fish colony. If there are many small females, the older ones become males. And vice versa. Others, like sea bass, have their sex identified from birth. But now there's a problem stemming from climate change.

Which?

— To maintain balance, the bass that spawned in cold water were female, and those that spawned in warm water were male. Since water temperatures are now rising, bass populations are becoming more masculine. There's an imbalance.

Do fish take care of their young?

— Fish don't. They fertilize in the water, meaning some release eggs, others sperm, and the fertilization process is done in the water, and that's it. The difference is mammals. In this case, like the whale, the sperm whale, the dolphin, and the orca, they all care for their young because they must suckle. We're talking about animals that walked on land and have returned to the sea.

You say that orcas and seals walked?

— Yes, but let's talk about millions of years ago. They came out onto land and returned to the water. Not in the form they have now, but that's why they have lungs, not gills. They have to come up to breathe.

Climate change. Give me an example of how it affects us in our country.

— Have you heard of gorgonians? They're the beautiful corals found, for example, off Cap de Creus. The temperature rises so much in summer that many of them have died. Fish have an advantage over corals: they can move. They go to the bottom of the water in search of cooler temperatures or they migrate directly. This also poses a problem.

Because?

— Because the Mediterranean gets so hot in the summer that tropical fish from the Red Sea enter through the Suez Canal. Before, temperature was a barrier.

Which ones have entered?

— The puffer fish, which has toxic guts. People have caught it, eaten it, and died. The risk of temperature rise for the Mediterranean is tropicalization and the loss of native species.

He has spent 30 years at the Aquarium.

— For a time, small sea breams were disappearing from an aquarium. We couldn't understand anything.

Many famous people must have been there too, at the Aquarium.

— I was very excited to meet Miquel Luque, an Olympic champion with a disability. And Messi, who came when he was very young, driving a Fiat Uno with his father. He was very coordinated. We did the exercises once and he was perfect right away.

We're closing in on the Mediterranean again. How would you define it?

— Cradle of civilization.

I thought he would give some biological data.

— It's a special sea because it's very warm in summer and cold in winter. But its main characteristic is that it's surrounded by cities. And civilization, as we know it today, is born from the communication between these cultures through navigation. Because culture was forged by the sea. And the Mediterranean is the cradle of culture as we know it today.