Bio-physical modeling of freshwater fish habitats.

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***The knowledge that humans have about living organisms is measured largely by the extent to which we understand how many organisms there are, where they are located, and what will be their future abundance and distribution. The general objective of my research program is to contribute to a better understanding of the distribution of organisms. This general objective is achieved by studying fish living in rivers and lakes because a number of indications suggest that human activities particularly affect fish from these ecosystems.***Fish habitats may be defined as areas required by fish to carry out their life processes (survival, growth, and reproduction). Habitat loss has been identified as the major cause of the decline of freshwater fish populations. Human activities, from urbanisation to industrial development, may be expected to continue infringing on aquatic ecosystems. The number, and the surface area, of freshwater ecosystems impacted by human-induced disturbances may be expected to increase. Preserving or restoring habitats, and therefore, conserving or re-establishing fish populations, require knowledge about what makes a good habitat for fish.***Habitat models are mathematical relationships between elements that describe the wellbeing of fish populations at a series of sites, and the environmental conditions found at these sites. Developing these models requires the estimation of elements that describe the wellbeing of populations and the environmental conditions that allow fish to thrive. The abundance of fish populations at sites has been taken as an index of the well being of populations at these sites, but habitat models that attempt to predict fish abundance do not always perform well. It has been suggested that this may be related to the inadequate estimation of fish abundance at sites. However, it has also been argued that other indices of fish wellbeing would be more appropriate. These refer to elements such as fish growth, behaviour, or physiology. The specific objective of my research program is to conduct laboratory experiments and field observations to find solutions to problems that impede the development valid habitat models. It is expected that, once these models are developed, they can allow us, to identify what can be done to maintain, or improve, the condition of fish populations and, to predict, and eventually minimize, the effects of human activities on fish populations.*** **