“ Rubber bream ” is the expression with which the phenomenon that strikes a fish – the bream – with its delicious and once highly sought-after meat is commonly indicated.

For some years, some professional fishermen and sportsmen have complained that, often, specimens caught in adulthood become inedible once cooked : the meat would appear hardened and would lose the organoleptic qualities so much appreciated.

The sea bream: from king of the table to inedible fish

The bream (or diplodus ) is a species belonging to the family of the Sparidae ( Sparidae ), the same as the snapper, sea bream and sea bream.

It is a very widespread fish in the Mediterranean , in the Atlantic Ocean and is present in all Italian seas. It lives near the sandy and rocky coasts, from a few meters up to 70 meters deep. In Italy it is mainly present in Sicily, Sardinia and the Tyrrhenian Sea, where the specimens are larger.

Its white meats – ideal for cooking in the oven, salt and grilled – have always been considered very valuable. 

Until that, an increasing number of reports from sport fishermen caused the case to break out: many of the bream caught, once cooked, took on the consistency of a tire .

The phenomenon has intensified since about 2005, animating on the one hand the debate in specialized magazines and forums , and on the other hand causing the market value of fish to collapse , which is in fact disappearing from the tables. 

Spain, Greece, Tunisia, France, Italy: all of the Mediterranean coasts are affected by the problem.  

In the seas of the beautiful country, the phenomenon emerged in a worrying way in 2013, when it was found for 70% of the bream caught ,in many cases reaching the totality of the catch in 2014.

The potential causes

Many have carried out research to identify the causes of the anomaly starting from the formulation of some hypotheses. From the excess of phosphates, to the presence of mercury and lead, many of them are attributable to marine pollution . 

On the side of this, we examined the habits of the bream which, in recent years, is in fact changing its way of eating. Specifically, fish, mostly off the coast, eats molluscs and algae that it was previously unaware of, with possible repercussions on its organism and on the properties of its own meat.

Caulerpa cylindracea, an alga in the sights of researchers

In 2015, a study by the Laboratory of Zoology and Marine Biology of the University of Salento brought to light what could be one of the major causes of the phenomenon.

According to what has emerged, part of the blame must be attributed to Caulerpa cylindracea , an invasive algae native to South Australia . 

Professor Terlizzi, coordinator of the project, said at the Mattino di Napoli : “We conducted our study on 150 individuals of white bream. They found that seaweed is now a very important component of the fish diet. Following this it was shown that the bream accumulates one of the algal secondary metabolites, the alkaloid caulerpine, and this has been used by us as a marker of exposure to the alga and correlated to the cellular and molecular responses measured in fish. The physiology of the sea bream is compromised, with long-term repercussions both on the reproductive potential and on the nutritional quality of the meat, with a significant depletion of polyunsaturated fatty acids of the omega-3 and omega-6 series which thus give the cardboard-like flavor after cooking. of the bream “.

The research, which lasted seven years, was funded by the Ministry of the Environment and the European Union , and was made possible by the creation of a dense network of collaborations between European universities.

Sarago of gum, searches continue

Research to determine the underlying causes of the phenomenon, however, continues.

The “rubber bream” is in fact the central theme of a project that involves the oceanography laboratory of Civitavecchia, the Fipsas ( Italian Federation of Sport Fishing Underwater Activities ) , the Cursa ( University Consortium for Socioeconomic Research and the Environment ) , the Biologists Society of Civitavecchia , in collaboration with sport fishermen.

The objective of the survey, which can count on the support of the Lazio Region, is to map the allochthonous alga Caulerpa Racemosa, in order to understand if there is a connection between its diffusion and the modification – worrying for its environmental implications and for the potential, not determined consequences on human health – of the flesh of the white breams.