Diadromous Fish Ecology and Conservation

Diadromous fishes encompass species that undertake regular migrations between freshwater and marine environments. These migrations, classified as anadromy, catadromy or amphidromy, enable exploitation of spatially separated habitats for feeding, growth and reproduction. The ecological significance of these species lies in their role as vectors of energy and nutrients across ecosystem boundaries, supporting riverine and coastal food webs. Diadromous fishes also underpin critical ecosystem services, including fisheries, cultural heritage and nutrient cycling. However, populations worldwide have suffered declines, primarily due to anthropogenic pressures such as river fragmentation, habitat degradation, overexploitation and climate change. Barriers to migration, notably dams and weirs, disrupt spawning migrations and impair recruitment, while alterations to flow regimes and water quality further challenge the persistence of these species. Contemporary conservation efforts encompass habitat restoration, installation of fish‐passage structures and adaptive management of fisheries, all underpinned by integrative ecological research. Advances in tracking technologies and modelling have enhanced understanding of migratory behaviour and habitat requirements, informing targeted interventions. Effective conservation demands coordinated actions across freshwater and marine jurisdictions, recognising the transboundary nature of diadromous life cycles.

Research from Nature Portfolio

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Diadromous Fish Ecology and Conservation publication trend

The graph below shows the total number of articles in diadromous fish ecology and conservation across all publications each year (not limited to Nature Index journals).

Technical terms

Diadromy: Migration between freshwater and marine environments as an integral part of the life cycle.

Anadromy: Life‐history strategy in which fish migrate from the sea to fresh water to spawn.

Catadromy: Life‐history strategy in which fish migrate from fresh water to the sea to spawn.

Amphidromy: Migration between fresh water and the sea for purposes other than spawning.

Ecosystem services: The benefits humans derive from ecosystems, including provisioning, cultural and regulatory functions.

Habitat suitability model: Analytical tool that predicts areas meeting environmental conditions required for species’ life stages.

References

1. The decline of the ecosystem services generated by anadromous fish in the Iberian Peninsula. Hydrobiologia (2023).
2. Dynamics of Two Anadromous Species in a Dam Intersected River: Analysis of Two 100-Year Datasets. Fishes (2021).
3. From the modeling of diadromous species’ marine distributions to the characterization of their current and future marine habitats. Frontiers in Marine Science (2023).