Work

Conservation Benefits of Lake Outlet Dam Removals: Reduced Mercury in an Apex Fish Predator

Year: 2025

Type: article

Abstract: ABSTRACT Biomagnification of environmental toxins is influenced by food chain length, which in turn is shaped by habitat connectivity and food web dynamics. Dam removals are increasingly used as restoration measures, yet their role in reducing contaminant exposure has rarely been quantified. We tested if mercury concentration in pike ( Esox lucius ) muscle tissue was reduced by removals of lake outlet dams in five oligotrophic, boreal lakes, using a before‐after design. For pike of average size (50 cm), mean mercury concentration decreased from 843 to 598 μg Hg per kg muscle tissue following dam removal, which corresponds to a 29% reduction. These results show that dam removal can lower mercury bioaccumulation in apex predators, providing an additional conservation benefit of restoring natural aquatic connectivity, with positive implications for both ecosystem integrity and human health.

Source: Aquatic Conservation Marine and Freshwater Ecosystems

DOI: 10.1002/aqc.70248

Authors: Johan Watz, Niclas Carlsson, Eva Bergman, Per Anders Nilsson, Olle Calles

Institutions: Karlstad University, Lund University

Language: English

Topic: Mercury impact and mitigation studies

Subfield: Health, Toxicology and Mutagenesis

Field: Environmental Science

Domain: Physical Sciences

SDGs: Clean water and sanitation, Life on land

Open Access status: hybrid

Estimated APC paid: $4,730