Fish Population Dynamic and Stock Assessment

1.6.1. Spatial and temporal variations

Fish ecologists and managers realize that all ecological systems exhibit heterogeneity and patchiness on a broad range of spatial and temporal scales. We all recognize that these patterns have fundamental effects on biological processes, dynamics of populations and ecosystems, our perception of the environment and, ultimately, how we sample and manage natural resources. Incorporation of space, time, and scale (and their interactions) in theories, modeling, and sampling has improved our understanding of how population dynamics and species interactions respond to the physical (e.g., temperature) and biological (e.g., prey density) spatial structure in the environment. Multi scale analysis has shown the existence of scale-dependent patterns that can be of biological or physical origin and that can have significant effects on biological processes. Recent advances in hardware and software technologies and analytical techniques have contributed to our abilities to acquire and analyze complex spatial data sets, and to model ecological processes, over a wide range of spatial and temporal scales. Despite these advances and our growing appreciation for the importance of space, time, and scale, it is still often ignored in field sampling and modeling programs that attempt to evaluate predator-prey interactions, fish growth and production, and sustainability of a fishery.