The enigmatic boto has long been protected from human persecution due to various myths and superstitions surrounding the river dweller, including some which state that bad luck will forever befall upon anyone who kills one. The species has thrived throughout much of the Amazon basin, and is one of the most widespread of the river dolphins.
Now, a team of scientists from Projeto Boto have reported that this protection has largly disappeared. The boto is being threatened by an unusual form of fishing, fuelled by demand for a catfish species known as the piracatinga, or mota.
Fishing for piracatinga
The piracatinga is a necrophage, making a living by scavenging on the remains of other animals which have died. This habit has earned it the colloquial name of ‘water vulture’. The species will even attack the bodies of people who have drowned, and so is considered inedible in Brazil. But piracatinga is highly prized in neighbouring Colombia, and traders will cross the border in search of it. Unfortunately, their hunting methods have followed, where dolphins are killed for the purposes of bait to trap the scavenger catfish.
Standing in the water at night with a characteristic wooden box, a large piece of boto flesh is submerged and soaked to attract piracatinga. The fish quickly come to take bites from the carcass, lured in by the scent of fat and blood. Once inside the box, large piracatinga are trapped and can be removed by hand, while the design allows smaller ones to escape.
To obtain boto meat, hunters encircle groups of the dolphins in bays and inlets using nets, then remove individuals from the water with harpoons. Surplus botos are often tied to trees using a rope or cable around the tail until needed later. The whole practice is illegal and abhorred by the vast majority of local people.
In one night, use of a large adult boto as bait may afford a skilled fisherman more than one tonne of piracatinga. Taking this into account, Projeto Boto was able to determine that up to 1,650 botos may be killed every year near the city of Tefé; only a tiny portion of the range of the boto. The true scale of hunting of the species is likely to be far greater given that the fishing for piractinga is now commonplace in the Amazon basin.
Around Brazilian cities, the catfish is often sold as ‘douradinha’, meaning ‘little goldfish’. Many Colombian and Brazilian people do not realise they are eating this scavenger fish, which is readily available in a variety of main supermarkets and fish markets.
At present, no significant action is being taken to prevent this inhumane and unsustainable practice in spite of many efforts to raise awareness. Projeto Boto continues to work with Brazilian authorities in the hope of ending the hunt, which, at its current rate, is likely to threaten the survival of the boto as a species.
Find out more about Projeto Boto’s work at their website: www.projetoboto.com.
View images and videos of the boto on ARKive.
Rob Morgan, ARKive Media Researcher