Can restaurants be the solution to the jellyfish population explosion? – 7/2/2023 – Environment

In the summer of 2013, Stefano Piraino was strolling along the rocky coast of Ustica, a small island off the coast of Sicily, Italy, when he found a jellyfish washed up by the sea.

He bent down and nudged her. Then, in an unplanned move, he took a piece of the dead animal and put it in his mouth. It was salty, crunchy, and sun-brown.

“[Era] very tasty”, recalls Piraino, who is a zoologist and evolutionary biologist at the University of Salento in Lecce, Italy. “It was the first time I ate one.”

He explains that after a few days dead on the beach, the jellyfish’s stinging cells are deactivated.

Still, Piraino recommends that people not eat jellyfish directly from the sea, as raw animals contain bacterial pathogens that can cause food poisoning (although in his case, possible bacteria would have been killed by ultraviolet radiation coming from the sun).

But Piraino defends the inclusion of these invertebrates in the menu. It is a possibility being explored by researchers, given the fish population that has been decimated by man and the increase in the world food crisis.

The problem

There have recently been numerous reports of jellyfish infestations – seasonal events marked by large and sudden increases in the population of these animals.

These population explosions throw ocean ecosystems out of balance and have the potential to damage biodiversity and reduce fish numbers.

If we do not act to curb this population expansion, the ocean will cease to be a place of fish biodiversity and become an ecosystem dominated by jellyfish, according to a 2009 study.

This theory is widely contested. Some scientists claim that there is no evidence of a global increase in jellyfish numbers.

A long-term review from 2012, for example, concluded that there is no concrete evidence of an increase in the jellyfish population. The study suggested that their populations may undergo oscillation cycles lasting about 20 years.

But there is little doubt that population explosions are becoming more common in some places. And they can have severe consequences for marine and human life.

If jellyfish can pose such a threat to our oceans and global food security, why not just eat them?

Jellyfish reproduce extremely quickly. Some species even have properties of near immortality: the Turritopsis nutricula, for example, manages to avoid death when injured by transforming into a less mature version of itself (known as a polyp). It’s like a butterfly becoming a caterpillar again.

The polyp can then produce identical copies of itself, so theoretically the jellyfish can live indefinitely.

This is just one example of the immense resilience and adaptability of jellyfish, which have existed for 500 million years on the planet. Jellyfish can buy time until favorable breeding conditions arise, resting for years on the ocean floor in their polyp state, maturing and spreading only under ideal conditions.

Jellyfish also manage to benefit from human activities that harm other marine animals. They need very little oxygen to survive, for example. As a result, unlike other marine species, jellyfish are able to grow in places affected by water runoff from agriculture, which reduces oxygen levels in seawater.

But jellyfish proliferation, unfortunately, can have cascading effects. When they move into an area, other species have difficulty recolonizing it, even after oxygen levels return to normal. This is because jellyfish love to feed on fish larvae.

It’s difficult to predict exactly how jellyfish will behave in a warmer climate because not much historical data exists on them, according to Monty Graham, director of the Florida Institute of Oceanography in St. Petersburg, in the United States.

“A few decades ago, nobody really paid attention to jellyfish,” he says. “But jellyfish are very sensitive to climate cycles. And, by extension, they will also be very sensitive to long-lasting climate change.”

Historically, jellyfish have been controlled by marine predators such as gulls, sea turtles, fish and whales. But the population of their predators has been declining, due to a combination of factors including overfishing, climate change, pollution and habitat loss.

Around the world, jellyfish outbreaks are devastating the fish population, not to mention the fishing and tourism industries, to name a few.

In 2007, the entire Irish salmon industry was wiped out by the infestation of millions of jellyfish, in an area of ​​26 km² by 10.7 meters deep. They infested the cages of salmon farms, killing over 100,000 fish.

In Japan, fishermen have observed the extraordinary growth of Nomura jellyfish every year since 2002. This species can reach two meters in diameter and weigh up to 220 kg.

The giant jellyfish have devastated coastal life, at an estimated cost of billions of yen to the Japanese fishing industry.

“Some regions will experience increases in areas populated by jellyfish, their numbers and the duration of breeding, especially if we continue to put pressure on the fisheries found in the ecosystem,” explains Graham.

What if we eat them?

The sea provides a significant portion of the proteins consumed by humanity.

In 2020, the fishing industry caught around 112 million tonnes of aquatic organisms, according to the Food and Agriculture Organization of the United Nations (FAO).

And as the global demand for food increases, serious questions remain about our nutrient sources.

Some scientists, like Piraino, believe that one solution is to broaden our sense of taste. He suggests that, while the world faces the urgent need to seek sustainable food resources, one way to meet the demand is to try to integrate new foods into traditional recipes and local cuisine.

“Perhaps the time has come to add a new item to our menu: jellyfish”, says Piraino.

Jellyfish are consumed throughout Asia, but they are still rare in Western restaurants.

In China, for example, jellyfish has been consumed for over a thousand years. Jellyfish salad is a popular delicacy in the country.

They are rich in protein and the microalgae inside the cells of some jellyfish are high in fatty acids. This practice has yet to catch on in the western world, but some restaurants are encouraging their diners to embrace the unknown.

The entrance to the kitchen at Benu restaurant, in San Francisco, USA, is similar to most others in the city: a calm anticipation of the buzz that builds towards the imminent chaos of service, while the conversation of customers invades the kitchen. But unlike most other fine dining establishments, there is one special item on the menu: jellyfish.

Jellyfish graces a dazzling dish, delicately enveloping a single shrimp, accompanied by caviar and horseradish. It’s a “very affordable way” to taste jellyfish, according to Corey Lee, founder of Benu.

Lee hails from South Korea, where he grew up eating jellyfish. He says the animal was something “delicious and underappreciated” that he always wanted to share with his customers.

Jellyfish has been served in a variety of ways since Lee opened his restaurant in 2010, which now has three Michelin stars. Another way is fresh in a beef consommé.

“The ocean flavor provides a strong contrast and salinity to the rich, gelatinous soup, while its choppy texture is reminiscent of long-cooked beef muscle,” explains Lee.

But despite its appeal to adventurous consumers in the Western world, jellyfish are not a viable substitute for fish or other protein sources when considering what’s better for the environment.

It’s true that broadening our taste buds to include alternative protein sources is vital to help curb climate change, but jellyfish may not be the solution.

Firstly, jellyfish are 95% water. The remaining 5% contains your essential nutrients. This mass-to-nutrient ratio means that it is a rather inefficient source of protein.

“Eating them is a lot of effort,” says Graham. “A lot of energy is spent in the process, because they have a lot of water. They are not very good to eat either.”

“They’re probably more useful as a type of collagen rather than a protein per se,” says marine biology professor Jonathan Houghton of Queen’s University Belfast in the UK. “But certainly not as a substitute for fish, which is several times better as a potential food source.”

There are several companies that already use jellyfish as a substitute for bovine and porcine collagen, often used in human medical treatments. British company Jellagen, based in Cardiff, Wales, claims that jellyfish collagen offers a better alternative because its collagen is compatible with a wide range of human cell types.

stubborn jellyfish

But the fact remains that despite widespread consumption of jellyfish across Asia, infestations are still a problem.

Graham points out that eating jellyfish may reduce some of the pressure on the fish population, but it will not solve the underlying causes of jellyfish infestations, which are indicators of what is happening in the world’s oceans.

“If you take fish out of an ecosystem, the tendency is for the jellyfish to do very well,” he says.

Jellyfish thrive under conditions created by humans – particularly overfishing, warmer waters, pollution and coastal urbanization, which provide ideal conditions for jellyfish to grow. And the fact that more jellyfish exist certainly demonstrates how endangered our oceans are.

Jellyfish populations have always fluctuated naturally over time, as they are governed by natural weather cycles. The question, according to Graham, is “What human-made changes will force the trajectory of ecosystems to change forever?”

What also needs to change is our attitude towards food, according to Lee. “I’m not a marine biologist, but if people start consuming jellyfish as vigorously as we consume other seafood, I believe there will be adverse consequences as well.”

This point is highlighted in a 2021 study of the cannonball jellyfish fishery in Mexico.

Over the past 20 years, interest in this type of jellyfish has exploded after investors identified the region as teeming with the species. At the height of the process, in 2011, almost 40 thousand tons of jellyfish were captured. Most of them were exported to China.

But the overexploitation of these animals has caused a drastic reduction in their population since that time. The title of a 2015 study perhaps sums it up: “We shouldn’t assume that fishing for jellyfish will solve our jellyfish problem.”

What can really help resolve this is managing fish stocks responsibly.

read the original version of this report (in English) on the website BBC Future.