The Silent Threat of Mercury in Tropical Fisheries: A Danger to Food Security and Livelihoods

• A groundbreaking study recently published in the journal Environment, Development and Sustainability sheds critical light on the widespread issue of mercury contamination in small-scale tropical fisheries. The research, conducted by a team of investigators and students from various universities in Brazil and the Mediterranean Institute for Advanced Studies (IMEDEA, UIB-CSIC), integrates local ecological knowledge from fishermen with advanced ecological network analysis to assess the impact of mercury contamination on fish use and community livelihoods in Brazil.

Small-scale fisheries, crucial for the livelihoods and food security of millions in developing countries, are increasingly threatened by anthropogenic environmental changes, especially heavy metal contamination. Mercury pollution, primarily from artisanal gold mining and industrial activities, poses significant health risks, particularly in regions where fish are a primary source of protein and income.

The study focuses on two distinct regions: the Tapajós River in the Amazon basin and the coastal bay of Ilha Grande and Paraty. Using interview data from 849 fishermen in 64 communities, the researchers constructed socio-ecological interaction networks to identify the main fish species consumed and traded by these communities. They then assessed the potential impacts of mercury contamination by comparing networks that included all fish species with those excluding species known to have high mercury levels.

Image: Tapajós river, one of the places where the research took place.

The results reveal a complex scenario where the removal of mercury-contaminated fish would significantly impact fishing communities. In the Tapajós River, excluding contaminated species like tucunaré and large catfish would increase fishing pressure on other species, reducing food supply and income opportunities. Coastal communities exhibited greater fish species diversity, potentially offering more resilience; however, key species like groupers raised significant concerns.

"On our planet, all systems, whether natural, social, or economic, are interconnected, forming networks that overlap in layers and are related through a few key entities. In the case of fishing, understood as a cultural, provisioning, and economic activity, these key entities are represented by a limited number of essential species. If these species are compromised, the system can collapse on multiple levels. To ensure the food security of local communities, it is crucial to focus our conservation and management efforts on protecting these species," declares Andrés Ospina-Álvarez, one of the study's signatories.

The research highlights the urgent need for integrated approaches to manage mercury contamination and its socioeconomic impacts. Effective mitigation measures must include reducing illegal gold mining, controlling industrial discharges, and promoting sustainable fishing practices. Additionally, raising awareness about the risks of mercury and monitoring contamination levels in fish are essential steps to protect the health and livelihoods of vulnerable fishing communities.

Link to the artícle:  https://link.springer.com/article/10.1007/s10668-024-04990-y