Symposium 2006: Fish Population Structure: Implications to Conservation,
University of Aberdeen, 10 -14 July

dvice on fish dynamics and the sustainability of fishing practices is often based on a spatial scale that is different to that of the exploited populations. Failure to recognise the nature of structuring has been associated with the loss of genetic diversity and population instability. This symposium will address individual and population level approaches to the analysis of population structure in fish and the implications this has to their conservation and management. By bringing together researchers working in all types of marine and freshwater ecosystems the symposium will provide a timely overview of this rapidly developing field of fish ecology.

Themes

1. The nature of structuring
Fish biologists are increasingly turning to population theory to better understand and model their focal systems. This section addresses the application and development of theory to describe the spatial dynamics of fish populations, including concepts such as patchy, meso- and meta-populations.
2. Mechanisms involved in structuring
Environmental factors affecting dispersal and migration are important in the formation of reproductively isolated populations. This section will address how such mechanisms operate. Studies using 3D hydrodynamic models, otolith chemistry and electronic tags to study fish movements and behaviour should be particularly relevant to this section.
3. Comparison of divergence in life history and morphological traits
Populations may differ in their response to environmental change due to heritable genetic differences in life history traits. Our understanding in this field has greatly advanced in recent years through common garden and genomic approaches as well as new theoretical developments. This section will address local adaptation in life history and morphology and interactive effects with body size and the size structure of the population. Studies aimed at determining the level of correspondence between the degree of adaptive divergence and that found at presumed neutral molecular markers will also be particularly relevant to this section.
4. Effective population size and changes in the genetic structure of fish populations
Knowledge of the effective size of a population and of changes in its genetic structure over time are both essential for a comprehensive assessment of that population’s potential for persistence (risk of extinction) and productivity. Although effective population size can and has been estimated for fish from demographic data, less laborious and more precise estimates may be obtained using genetic markers where the basic premise is that random changes in allele frequencies through time will be inversely related to effective size. Facilitated by progress in analytical approaches as well as in laboratory procedures, estimates of effective population size based on temporal changes in allele frequencies have recently been made available for a variety of marine as well as freshwater fish. This section will address the estimation of effective population size of fish populations and will include studies examining temporal changes in the genetic composition of populations.
5. Stock dynamics and conservation in exploited species
Advice on fish dynamics and the sustainability of fishing practices is often based on a spatial scale that is different to that of the exploited populations. However, the presence of populations with differing dynamics and responses to environmental variability may be important in sustaining the overall productivity of managed stocks. This section will deal with management and modelling approaches that consider population structuring in the assessment of stock dynamics and conservation