Effect of Enrichment in the Hatchery on the Performance of Brook Trout and Atlantic Salmon

Fish stocking has been an important tool utilized by fisheries professionals for many decades. By artificially spawning and rearing fish in a controlled hatchery environment, it is possible to produce large numbers of fish that have a high survival rate while in the hatchery. This method can result in thousands of fish available for supplementing or reestablishing fisheries. However,many of these fish do not survive when stocked into the wild. If you compare the environments in which we raise fish for stocking and the environments we expect them to survive in, there are many apparent differences. Previous research suggests that hatchery fish exposed to altered rearing environments behave more flexibly. Fish raised in plain hatchery environments have little exposure to complex environments that more closely resemble natural streams and lakes. By creating environmental complexity and variability during a fish’s residence in a hatchery environment, fish may have the ability to learn and alter behavior in ways that increase post-stocking survival. Here I investigate the addition of variability in the environment of hatchery reared brook trout (Salvelinus fontinalis) and Atlantic salmon (Salmo salar), by assessing behavioral changes and post-stocking survival in several Adirondack lakes. My findings show several changes in behavior prior to stocking, as well as a survival advantage in a controlled laboratory setting. However, it did not result in increased recapture rates when the brook trout and Atlantic salmon were stocked into Adirondack lakes and ponds.