Reproductive Success in Brook Trout

Brook trout are in a family of fish known as salmonids. The species is native to Eastern North America, residing in clear, cold headwater streams and lakes. Brook trout's scientific name, Salvelinus fontinalis references the fact that they require cold, oxygenated (fast-moving) water to survive such as that found in springs or 'fountains'. Brook trout reproduce each year in the fall. The female (bottom fish in picture) selects and competes for an area of stream to construct her nest. Females prefer areas that have gravel substrate (streambed lining) and upwelling of water to keep their eggs clean and well oxygenated. Once a site has been retained the female digs out a hollow in the gravel by lying on her side and using her caudal fin (tail). This hollow nest is referred to as a 'redd'. While the female is constructing her nest, male brook trout (top fish in picture) are busy competing with one another to obtain mating access. During the breeding season males undergo changes in body shape and coloration which include a hooking of the jaw referred to as a 'kype', and a red/orange coloration of the abdomen. These changes are believed to occur as a result of sexual selection. This means that males displaying these characteristics have been more successful at reproducing, and thus passing on their genes. I am interested in what other characteristics determine reproductive success over the entire lifetime of an individual, such as animal movement, growth rate, and age at maturation. To do this I monitor size and location data for individually tagged fish, and analyze these data against the number of offspring that they produce. Because there is no parental care in brook trout, offspring must be assigned to parents through the use of genetic techniques. The outcome of this research will provide a better understanding of how individuals influence populations, and will help to manage populations as habitat becomes more degraded because of development, pollution, and water usage.