What to do about invasive species? Eat them!

12 May 2019

Blue crab, smooth cornetfish, Asian tiger shrimp, rabbitfish, lionfish: names that call to mind warm seas and exotic landscapes, yet they’re being found more and more often in our fishers’ nets, and consequently at our fishmonger stands and on our dinner tables.

These are invasive species, fish that have been introduced, one way or another, into a new environment.

The phenomenon, defined as the tropicalization of the Mediterranean and closely connected with global warming, has been well known for some time: the first alarm sounded more than 30 years ago. “Initially people asked us the most bizarre questions, as if they were Martians just landed,” laughs Franco Andaloro, biologist and director of the Sicilian center of the Anton Dohrn Institute for Biology, Ecology and Marine Biotechnology in Naples, and member of the Slow Fish scientific committee. He’s recently published an updated list of all the alien species in the Mediterranean together with an international group of researchers.


The smooth cornetfish (Fistularia commersonii). Photo: agenpress.it


“The most direct way is natural: you open a path and the fish swim toward the seas best adapted to their needs, they migrate. That’s what happens with the so-called Lesspian migrants, who came up from the Red Sea through the Suez Canal, like the rabbitfish and the cornetfish. Many species are similar to our mullets and amberjacks and often consumers often can’t tell the difference. Then there’s the voluntary introduction of species by humans, through aquaculture, which has only recently been regulated. This has led to the diffusion of Philippine clams, which are now more widespread than native clam species, and Asian tiger shrimps, which are now commonly captured along with our native striped prawns.”

Today in the Mediterranean there are over 1000 alien species, many of which are fish. Of these only 20 are present in Italian waters, while the majority are found along the coasts of the Eastern Mediterranean in Turkey and Lebanon, where alien species represent more than 50% of the catch. Their expansion into the Central and Western Mediterranean is simply a matter of time.”


The red lionfish (Pterois volitans).


From an ecological point of view they’re defined as a marine pest, and to keep them at bay we have three routes:

  • prevention, by controlling their introduction, for example via aquariums and ballast water from ships;
  • mitigation, i.e. protect our environment, because invasive species are more widespread in degraded seas where native species are not able to respond or defend themselves;
  • adaptation, by limiting damage with alarm systems for dangerous species and the introduction of edible species into our diets.


Lake Iseo – Wel’s catfish

It’s a classic case of human interference in ecology: from the fresh waters of Eastern Europe and Russia it was brought to the rivers and lakes of Northern Italy half a century ago, when native species where threatened by changes to the ecosystem. It’s a species loved by game fishers for its fight and difficulty of capture. Its position at the top of the food chain has allowed it to expand at the cost of pikes and tench. So we gave free reign to the imagination at Slow Fish with Vittorio Fusari of Balzer in Bergamo, who presented a Wel’s catfish ceviche in his Dinner Date. “It’s an invasive species introduced for sport fishing, with a devastating effect on the ecosystem,” Fusari explains. “We’re experimenting with a few plates, to try and transform a threat into a resource.”


Mehmet Can Görgün.

Turkey – 35 invasive species

Climate change is the biggest enemy of fishing according to Mehmet Can Görgün, who recounted his experiences with his fishers’ cooperative in the Slow Fish Arena. Species moving up into the Eastern Mediterranean are still unfamiliar to a lot of people, so the Akyaka Fisheries Cooperative organized an event along with the Mediterranean Conservation Society to promote their consumption. “During the event we taught people how to cook these species and tasted them,” Mehmet explains. “The impact was surprising. Before the festival only 10% of fisher incomes came from invasive species, but now that’s between 30 and 60%.”

Mexico – Red lionfish and Amazon sailfin catfish

They suffered the consequences for the marine ecosystem, the economy and food security provoked by the greed of a strikingly beautiful fish. We’re talking here about a small-scale fishing community on Mexico’s Caribbean coast, and the red lionfish, 30 centimeters long and equipped with poisonous spines. It’s an invasive species from the Indian and Pacific Oceans and its appearance on the East Coast of Mexico has caused serious damage to the equilibrium of the food chain, pushing some commercially-fished species like the lobster and the goliath grouper to the brink of extinction. That was until three years ago, when the Asociación de Pescadores Artesanales del Caribe Sur (Asopacs) presented a protocol to Environment Minister of Costa Rica for the capture and commercialization of this invasive species. The initiative soon spread to other countries, and the pez león is now a prized plate in restaurants across Central America.

The other fish which has become a resource is the Amazon sailfin catfish, which has represented an ecological threat to the Usumacinta and Balsas basins since 2014, as well as for the Hondo river. The fish reproduces along the river banks and its nurseries are so vast that they contribute to coastal erosion, destroying vegetation on the riverbed and blocking sedimentation, as well as forcing native species to move. In the battle against the sailfin catfish we’re still a little bit behind, but its skin is now being used to make shoes, and its meat is appreciated. The director of the Programas de Amigos de Sian Ka’an A.C, Liliana García Ramirez, shared her experiences with Slow Fish Caribe. Slow Food is now working in all the countries of the Caribbean with the objective to reinforce conservation models and promote the sustainable use of resources.


Bluefish (Pomatomus saltatrix).

by Elisa Virgillito
[email protected]



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