Habitat Selection Under Predation Hazard: .
Ecological Scientists believe that some organisms may choose habitats or foraging sites based on both the net energy return to the organism and the mortality risk involved for the forager. The rate of foraging often decreases according to certain changes in their behavior. An example of these changes can be when the organisms shift habitats due to the presence of predators and also display behavioral changes from predator intimidation. Gilliam and Fraser's study is based upon the organismal level, meaning that organisms must find a balance between foraging a sufficient amount of food and at the same time avoiding predation. Juvenile creek chubs were used in a model to determine preferred foraging areas that minimize the mortality rates, with the main objective being able to acquire an adequate net energy gain. The motivation here relies on whether or not there is an increase or decrease in mortality rates. Therefore, forcing the minnows to shift foraging sites to an area where there is more of a threat to the minnows but it is complimented by a plethora of resources. The significance in devoting an entire study to this subject is that it's the first in its field and that it helps future ecologist interested in this field of study to understand the behaviors of minnows while foraging and avoiding predation.
The experiment was conducted using wooden channels consisting of an area of .42m x 2m in the stream. A mesh wire cloth was used to divide the central refuge and also to prevent a predatory adult creek chub from passing into the experimental area. Predator and food densities were manipulated, which resembled local streams where adult creek chubs are the only piscivorous fish. The experimental area was cleaned daily with a suction pumped which prevented unwanted invertebrates from inhabiting the studied area. In order to measure the gross foraging rates, the Tubifex worms were allowed to burrow in plastic trays consisting of mud for 30 minutes prior to them being added to the foraging areas.