The Drought in the Amazon and Its Impacts on the Region's Aquatic Fauna

According to the National Water Agency – ANA (2015), the Amazon Basin covers an area of approximately 6 (six) million km² and extends across 6 (six) countries, in addition to Brazil. However, despite its strength and magnificence, this river basin faces critical points of drought in rivers and water channels, triggered by climate change.

It is important to highlight that the recurring droughts in the Amazon in recent years result from the combination of complex anthropogenic and environmental factors. Thus, climatic events such as El Niño, La Niña, global warming, and rampant deforestation alter the region’s hydrological cycle, leading to decreased rainfall and rising temperatures (Zogahib et al., 2024). In recent decades, the Amazon has experienced several episodes of prolonged drought: the first in 2005, the second in 2010, the third between 2015 and 2016, and the most recent between 2022 and 2023. These events affect the biome in various ways, especially concerning aquatic animals that depend on water for survival (Andrade, 2024).

Caption: Igarapé dos Reis in Iranduba, Amazonas, with dozens of dead fish around some logs and boat engines in 2023. Source: Alberto César Araújo/Amazônia Real.

According to the National Institute for Amazonian Research – INPA (2024), the record drought in the Amazon Basin in 2023–2024 drastically impacted the population of fish and aquatic mammals in the region. In 2023, the Chico Mendes Institute for Biodiversity Conservation (ICMBio) launched the "Operation Tefé Dolphin Emergency" to address the environmental and health crisis affecting Lake Tefé, in the mid-Solimões River in the interior of Amazonas, a critical point of mortality for Amazon river dolphins (Inia geoffrensis) and tucuxis (Sotalia fluviatilis) due to the high water temperature. Approximately 153 (one hundred and fifty-three) dolphins were killed, including 130 (one hundred and thirty) Amazon river dolphins and 23 (twenty-three) tucuxis. It is noteworthy that Amazon river dolphins are classified as Endangered (EN) (ICMBio, 2022), and tucuxis as Near Threatened (NT) (ICMBio, 2018).

Caption: The image shows two ICMBio team members handling the carcass of a dolphin in 2023. Source: Agência GOV/ICMBio.

Furthermore, institutions such as INPA warn that during periods of intense drought in rivers and water channels, Amazonian manatees (Trichechus inunguis) suffer from stranding and, due to their exposure, often become victims of illegal hunting. It is worth noting that the Amazonian manatee is endemic to the region and considered Vulnerable (VU) on the extinction risk scale (ICMBio, 2022).

Caption: The image shows an Amazonian manatee being rescued in March 2024. Source: Wellyngton Coelho/Agência Pará.

The Amazonas State Research Support Foundation – FAPEAM (2024) states that hydrological events affect all aquatic life by interfering with river migrations, food access, and reproductive timing. Consequently, animals exposed to these conditions face greater stress factors, which limit their reproductive processes and, as a result, impact local biodiversity as a whole.

Given the above, the drastic climate changes and their impacts on the Amazon Basin are evident, seriously compromising environmental balance and the survival of the biome's aquatic species. The increasing mortality of fish and river mammals serves as a warning to society about the devastating effects of alterations in the hydrological cycle and rising water temperatures—impacts that are approaching irreversible levels of degradation.

In this regard, it is essential to strengthen and promote conservation initiatives like those led by ICMBio and other institutions. Finally, it is crucial to reiterate that protecting the Amazon means ensuring biodiversity for the planet.

Author: Bárbara Macedo Lopes – Creative Director of GEAS Brasil

Review: Iago Junqueira – Partner of GEAS Brasil through The Wild Place

REFERENCES:

National Water Agency (Brazil). Conjuntura dos recursos hídricos no Brasil: regiões hidrográficas brasileiras – Edição Especial. Brasília: ANA, 2015.

Amazon. [S.l]: Ministry of Environment and Climate Change, Dec. 28, 2021. Updated on Dec. 28, 2024.

Andrade, R.O. The drought that affected the Amazon in 2023 caused the largest drop in river levels ever recorded, and is linked to climate change, study shows. Jornal da UNESP, Apr. 24, 2024.

Brazil. Portaria MMA Nº 148, DE June 7, 2022. Official Gazette of the Union, Jun. 8, 2022.

Brown, S. As rivers dry up, manatees become exposed to hunting in the Amazon: The low water levels in Amazon rivers make it easier for hunters to target the animal’s meat. Fauna News, Oct. 11, 2024.

Costa, F., Marengo, J. Statement on the Amazon drought of 2023 and its unforeseen consequences. Study Notebook: Amazon Biome and Deforestation. IBAM - Rio de Janeiro, 2015.

Domit, C et al. Sotalia fluviatilis: Extinction Risk Assessment System for Biodiversity.

ICMBio. More than 150 dolphins die in the interior of Amazonas due to extreme drought: In Lake Tefé, with heat and extreme drought, water temperature reached over 39°C. [S.l]: Agência GOV, Oct. 16, 2023.

National Institute for Amazonian Research - INPA. Droughts and floods are expected to become more intense and frequent in the Amazon in the coming decades. Sep. 4, 2024.

Amazon Hydrographic Region. National Water and Sanitation Agency (ANA).

Zogahib, A.L.N et al. Climate change and its impacts on cities: a case study of the drought phenomenon in the state of Amazonas, Brazil. Research, Society, and Development, Sept. 26, 2024.

Rodrigues, D. Research finds that hydrological events affect the daily life of Amazonian fish. Decon/Fapeam, Jan. 16, 2024.