This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Ask how many Amazon river dolphins are left in the world, and the honest answer is that nobody knows, and this entry does not pretend otherwise. World Land Trust's own species page states plainly that no range-wide estimate of abundance or population trend exists for Inia geoffrensis, which is a genuinely different situation from a species whose population is merely small or merely declining: this one has never been counted across its actual range at all.
What does exist is regional evidence, and it paints a troubling picture even without a global total. A 22 year standardized survey along a fixed transect in Brazil's Mamiraua Reserve, published by Da Silva and colleagues in 2018, documented a sustained, steep decline over that period, with the local boto population falling at an average rate of roughly 6.7 percent a year from 2000 onward. The same region carries an unusual and specific threat: a fishery for piracatinga, a scavenger fish that has developed a taste for dolphin carcasses, which created a direct market incentive to kill dolphins deliberately for bait, estimated at 300 to 4,000 animals a year in that fishery alone.
A rate of decline without a starting total is enough to establish the IUCN's Endangered status, but it is not enough to say how close the species is to some absolute floor, or how the picture differs across the Orinoco and Madeira basins where less survey work has been done. That gap is real, not a matter of insufficient effort to find a number that is out there somewhere; it would take a coordinated, basin wide survey using the same standardized methodology already proven at Mamiraua, extended across the full range and repeated regularly, to close it. This atlas records that gap as an open question rather than filling it with an invented figure, the same discipline already applied to the honey bee's own population.