Native to the waters of the Danube, the Wels catfish (Silurus glanis) was introduced illegally in Italy in the 1950s by Lipovan and Eastern European fishermen. In a short time it occupied the entire basin of the Po river and its tributaries, before reaching the rivers of the center of Italy, the Tiber and the Arno.
It is a large fish that has no natural predators and that exerts a highly predatory activity on other fish species, thus altering the biological balance of aquatic fauna.
Its introduction into Italian waters in the second half of the twentieth century is due to food purposes: to make it proliferate in virgin waters to satisfy the wide demand of the Eastern European market. Not being a fish of local origins, in fact, it has never been present in the Italian culinary tradition which still finds it hard to consider it palatable due to the toxicity of the river waters in which it lives and its ugly appearance.
Tiber Monsters
Rome, Lazio. Francesco, 38, after the capture of a specimen of 2.28m in length.
Todi, Perugia, Umbria. To avoid damage to the fish, fishermen tie a bungee cord across the mouth and gill after catching to carry the exhausted fish to shore.
Pontecuti, Perugia, Umbria. The “Dead River” is a bend in the Tiber which emerged from the main course during the flood of 1557 and subsequent rectification works carried out between 1938 and 1940. Due to the low water and the weak water current that characterizes the stretch has become a fishing spot where live large fish in heat.
Fishing for this animal is placed in a situation of limbo between legality and illegality. The Italian law on fisheries establishes that the captured specimens must not be released as they are considered alien species as weeds, invasive and harmful to the Italian aquatic ecosystem because they threaten the native species, more valuable, now almost in danger of extinction due to voracity of this fish. On the other hand, however, there are no structures dedicated to the biological disposal of the fish caught, so the fishermen who prefer to abandon it on the river bank commit an environmental crime.
The Wels catfish are gigantic fish with a biomass ten to fifty times higher than that of native predators. Its daily food requirement is equal to 2% of body weight: it can exceed 3 meters in length and eat about 100 kg of fish per year.
The largest specimens can live up to 80 years and are locally called Tiber Monsters.
Since it has been present in the main Italian waters there have been numerous decreases – up to the complete extinction – of various native fish species such as: bleak, cheppia, lamprey, marble trout.
In addition to invertebrates, fish, eels, the largest fish even feed on small mammals and wild birds.
Montemolino, Perugia, Umbria. Valerio, 32, catches small fish to use as a bait for large catfish.
Montemolino, Perugia, Umbria. The Wels catfish is a predator that prefers dark or very murky waters to hunt and feed. It rarely moves during the day, and spends the hours of brightness holed up on the holes in the seabed. It moves especially at night approaching in shallower waters, sometimes even up to a few meters from the shore, looking for prey.
Montemolino, Perugia, Umbria. After a tiring struggle, Valerio drags a 2.12 mt long on his dinghy.
Rome, Lazio. The fish ranks at the top of the food chain. Its invincibility is due to the presence on the sides of the mouth of barbels, skin appendages with a sensory function. Thanks to the barbels, the Silurus glanis can identify its prey both in the dark and in the presence of high turbidity.
Saxa Rubra, Rome, Lazio. A fisherman reintroduces a specimen caught the previous night back into the water. Italian law prevents this and there are large fines for those who catch a catfish and do not kill it. The law, however, does not provide for the methods of killing and above all how and where to dispose of the carcass. To avoid leaving carcasses to rot in inappropriate places, sport fishermen prefer to put their prey back in the water after capture.
This particular catfish has colonized consistently all the fresh waters of the Tiber, above all because it is a fish with very few ecological needs: it does not need clean water, it loves mud and reeds, in which it remains hidden to rest during the hours. diurnal, while in the twilight hours and during the night it goes out hunting for other fish, birds or small mammals.
Due to its large size and its insatiable voracity it has placed itself at the top of the food chain. In some areas of the territory, measures have been taken to safeguard indigenous species, prohibiting fishermen from putting catfish back into the water (like any other invasive alien species).
Ponte Milvio, Rome. Antonio and Saverio carry a fish to the shore after being caught in the water.
Ponte Milvio, Rome. A specimen of fish lying on the bank of the Tiber while a fisherman stretches a meter on its back to measure its length.
Ponte Milvio, Rome. Immediately after the capture of the fish follows a real photographic ceremony. To celebrate the victory over the fight in the water, almost always tiring and exhausting, immediately after the capture the sport fishermen photograph the dying fish lying on the shore.
Pontecuti, Perugia, Umbria. The small Umbrian village is one of the oldest places to practice catfish fishing.
Pontecuti, Perugia, Umbria. Walter, 41, in his spot is waiting for a fish.
Its introduction into the ecosystem took place when the environmental situation of the rivers of northern Italy was more compromised by canalization and reclamation, which had eliminated reeds and areas of shallow water in the most impressive courses, very important for reproductive purposes for many species, including tench and pike.
The disappearance of the sturgeon caused by the construction of numerous dams, and the slow exit of the pike, have greatly favored the establishment of the catfish in Italian waters. The introduction of other alien species, such as crucian carp and bream, did the rest, providing abundant trophic resources for this large predator.
Ponte Salario, Rome, Lazio. 48% of Lazio’s river waters have a «bad» or «poor» ecological status index. The Tiber is the river with the highest number of crimes committed along its waterways that destroy its eco-sustainability: illegal fishing, failure to purify civil and industrial waste, pouring pollutants and toxic substances directly into water courses . Catfish live in particularly polluted waters for a long time, which is why it is not recommended for cooking.
Ponte Castel Sant’Angelo, Rome. The carcass of a catfish fish and a barbel released into the water dead after a fishing session.
Marconi Bridge, Rome. The skin secretes a gelatinous substance which, in addition to protecting it from disease, allows it to move easily among the rocks of the seabed without risking injury.
Ponte Flaminio, Rome. Emanuele, 32, begins his evening fishing session.
Mouth of the Tiber, Fiumicino, Rome. A fisherman at night moves on the river arranging bait.
Castel Giubileo, Rome, Lazio. The old bridge of Castel Giubileo is one of the most popular fishing spots in the Italian capital. The remains of the bridge that collapsed in 1951 have created deep holes and pits where fish burrow.
Castel Giubileo, Rome, Lazio. Salvatore, 22, after the capture of a small specimen of 1.20 cm in length.
Dam of Castel Giubileo, Rome, Lazio. The body of a catfish left on the edge of the dam.