The Arapaima is the largest freshwater scales fish in the world, reaching 3 meters in length and weighing 200 kg
In Portuguese, the name of the fish is Pirarucu: for indigenous native speakers of Tupi pira it means fish (as in piranha, pirarara, piracatinga) and urucu is red (like in urucum, a typical red seed across Brazil) and, therefore, this is the origin of the popular name of our Amazonian character today: Pirarucu, a fish that presents red bands on their scales.
In science the animal is known as Arapaima gigas. Arapaima seems to be a variation of the name that the Macuxi ethnicity gives to the fish: warapaimo. And gigas, as you might think; refers to the colossal size of the animal. Pirarucu is the largest freshwater fish in the world, reaching 3 meters in length and weighing 200 kg!
If you think the animal is tough, imagine that it has evolved to be piranha-proof, since the scales are large and very resistant, with an outer mineral layer, but also a thick inner layer of collagen that provides more protection and allows the perfect fit to give mobility to the animal, finally a chain mail (improved by the adherent material) embedded in the skin. Speaking of resistance, we can also mention the pirarucu tongue bone (the fish is part of a group that has a bony tongue, the order Osteoglossiformes) which after the animal is slaughtered is used by riverside dwellers as a grater (for grating cocoa, for example). Ah, dry scales can be used as nail file!
Another very peculiar characteristic of the pirarucu is its aerial breathing. Yes, that’s right, a fish that needs to rise to the surface to breathe! In the dry season it is very common to see local guides pointing where they saw the animal float and then it is sometimes possible to catch a glimpse of its red scales sinking back, but we usually only look in time to see the water spread by the movement and we hear the dry noise that the tail produces when it hits the river hard. The dry season is also the period when couples are formed, males can take on a more reddish color to attract the attention of females. Before the eggs are laid, the parents look for a suitable place for the nest, clean the area and dig a circular nest in the substrate, called by the locals a “big pot”. The parents’ care is intense (seriously, the male carries the fry in his mouth!) And lasts until the chicks are 6 months old.
Arapaima gigas was close to extinction due to the intensification of predatory fishing that extended from the 70s until the early 1990s. Not only were the natural stocks of pirarucu affected, but also the traditional populations that depend on artisanal fishing. In order to try to reverse this situation, the species started to be protected by law in 1996 and can be captured for commercialization only in specific cases, such as management. The Mamirauá Sustainable Development Reserve was the first place where sustainable participatory management of pirarucu was implemented in 1999, the protocol was systematized by scientists and technicians from the Mamirauá Institute for Sustainable Development (IDSM), but it includes the traditional knowledge of local artisanal fishermen. This management guarantees the continuity and quality of the fishing resource, traditional ways of life, the source of income of local people and the species, which continues to live quietly under the waters of the lake and the Mamirauá reserve and also in the symbol of the IDSM.
texto: Cynthia Lebrão
Imagens: Daniele Barcelos, Bernardo Oliveira, Edu Coelho, Ricardo Oliveira, Amanda Lelis