# Analyses of historical documents reveal past trends of exploitation of manatees ( Trichechus inunguis) in the Amazon Basin (16th-19th centuries)

## TL;DR

Historical documents show that manatees in the Amazon were heavily hunted from the 16th to 19th centuries, with thousands captured, providing insights for modern conservation.

## Contribution

Quantitative estimates of manatee exploitation in pre-20th century Amazon, revealing trends and underestimation of historical captures.

## Key findings

- 14,030 manatees were captured between the 16th and 19th centuries, likely underestimated.
- An average of ~14,000 manatees were hunted annually between 1843 and 1898.
- Capture trends increased from the 17th to 20th centuries in Brazil.

## Abstract

The West Indian manatee (
Trichechus manatus) and the Amazonian manatee (
Trichechus inunguis) have been exploited by different societies from ancient times to the present. Deploying the matrix of Indigenous knowledge and uses, the hunting of manatees was at the core of European colonisation strategies of the Americas within a framework of appropriation, use, and consumption of aquatic mammals spanning the (post)colonial period. Today, both species are listed by the International Union for the Conservation of Nature and Natural Resources (IUCN) as Vulnerable, and population trends are expected to decrease in the future. While the exploitation of manatees (in particular,
T. inungis) is well described in the 20th century, no overall quantitative assessments of such exploitation in the preceding centuries have been made. Here, we address this gap of knowledge through a systematic review of the literature, identification and review of documentary sources, selection and extraction of quantitative data, and contextual analysis through cross-analysis of historical documents of several types. Our quantitative estimates resulted in a total of 14.030 individuals captured, which are most probably largely underestimated. It corresponds to a biomass removal of 6.248,9 tonnes in a period of non-continuous 52 years between the 16
th and the 19
th centuries. Specifically, an average of c. 14.000 manatees were hunted between 1843 and 1898, comprising 91% of all captures prior to the twentieth century when another point of accelerated extraction occurred. We determined a trend of increasing captures from the 17
th to the 20
th centuries, for Brazil, but an important lacuna of data for the 16
th century, and pre-European contact, persists. However, the results inform current and future conservation measures for the species, while also including historical, cultural, traditional, and indigenous perspectives about the use of aquatic resources.