Theme session N
Population status, life histories, ecology, assessment, and management of diadromous fishes
Thursday 21 September, 10:30–12:00 & 14:00–16:00
Room: Plenary ballroom A, B, C, D
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Diadromous species use freshwater environments for reproduction and marine ones as feeding areas or vice versa, or live their entire life cycle in a transition zone between the two. While some diadromous fish species like salmon and eel are globally famous and highly valued, others attract far less attention from policy-makers, scientists or stakeholders but are likely to make crucial contributions to complex marine, transitional and freshwater ecosystems. As migratory fish, these species face environmental and human pressures in a variety of habitats that are often regulated and managed by overlapping local, regional and even international agencies with legislation that differs in scale and purpose.
Many of these species are protected under the Bern Convention, European Habitats Directive, CITES, IUCN and additionally also in national regulations. A number of species are already known to be in great difficulty in most of those countries whose rivers drain into the Atlantic Ocean and its marginal seas. Examples are included in the side bar on the right. Water quality, migration barriers such as dams, and intense and widespread human alteration of estuaries and rivers are common threats for these species. Across a large scale, climate change can affect migration routes, the extent of estuarine habitat, and the balance between species. However, most of these species are not assessed nationally or internationally (e.g. by ICES) and thus, more information is needed on the current status of diadromous, data poor fish species in the context of international or national classification schemes.
Despite pressures on these fishes, a few well-known species like striped bass have recovered significantly due to management interventions, while others like Atlantic salmon and European eel remain in a perilous state. Other species have received little to no attention. We raise the need for more information on the status, current threats, and restoration possibilities for other more poorly understood diadromous species, as well as examples of new possibilities in management and restoration for viable fisheries.
The conference presents a unique opportunity to bring together North American and European researchers working on similar species but in very different political and geological settings. We see this as an opportunity for an exchange of ideas, information and new techniques for data collection, management and conservation of poorly understood diadromous species.
We invite researchers working on any species of diadromous fishes in Europe or North American, in freshwater or marine environments, to highlight gaps and opportunities in enhancing conservation and management by contributing papers in the following topic areas:
Status, distribution, ecology or biology of poorly understood diadromous fish species
Approaches for systematic monitoring of poorly understood diadromous species, including:
- Stock assessment methodologies for key species of interest for which assessments are currently not available or difficult
Ecosystem approaches for poorly understood diadromous fish, with science and advisory requirements relating to environmental drivers.
The integration of data poor diadromous fish into fisheries management - needs and implications
Using some species as index species (e.g. stickleback)
- Lessons learned from Europe or North America that might help management and conservation of functionally similar species
- Impending threats, particularly invasive species (e.g. round goby) or interactions with other species undergoing range expansion
- Physiological drivers controlling the movements of diadromous fish - gaps in knowledge
