Furthermore, we have reasons to be concerned about diseases and parasites. Farmed fish are not the only contributor to the wild fish decline, but their continued escape and interactions are obstacles that have to be overcome if the wild populations in this region are to recover. Exotic Species Introduction Exotic species, broadly defined, are those that people have moved outside their natural range. As these ships discharged their ballast water in order to take on cargo, the larvae were released into brave new worlds. Once the individuals of the exotic are free in a new habitat, their immediate concerns are to survive and reproduce.
Successful invaders tend to have a suite of characteristics that facilitate their colonization.
The frequency at which the invader is introduced into an environment, and the absence of competitors at the time it arrives also facilitates colonization success. Depending on the circumstances an invader will need combinations of a few or all of these characteristics to prosper. By contrast, unsuccessful invaders die. Most of our core agriculture products like grains and cows are exotics that have been moved throughout the world. The benefits to humans of these introductions have been enormous, and it is difficult to imagine life without them.