Browsing by Author "Gahr, Carolyn"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Analysis of home range in Northern Pike (Esox lucius)(2011-02-03) Gahr, CarolynNorthern pike (Esox lucius) are a freshwater predator that obtains their prey via ambushing. Studies have found that the activity of pike is correlated to their size such that larger pike move farther and faster (Eklov 1992). However, compared to other predatory fish pike move less frequently and are independent hunters (Eklov 1992). Pike are most commonly found in shallower water and prefer vegetation for cover in order to ambush their prey. In particular, larger pike have been shown to prefer shallower water closer to shore than the smaller pike (Jespen et al. 2001). In addition, pike have been found to be most active in low light conditions, especially around dusk and dawn, although some studies indicated no variation in activity over the 24 hour day (Jespen et al. 2001). This study focused on determining the home range and territory of northern pike in Lake Itasca over a two week time frame. The home range of an animal is the area that is used in the course of normal activities which contains sufficient resources to survive and reproduce. In addition to determining the home range, the territory, or the region which the animal defends, was also measured by looking at where the pike spent the most amount of time. Some factors focused on were the correlation between pike size, area of the home range, and the depth of the water. We hypothesized that larger pike would inhabit shallower water and have a larger home range than smaller pike.Item Habitat complexity and shoaling behavior in Pimephales promelas(2011-02-01) Gahr, CarolynHamilton’s selfish herd theory dictates that individuals will seek protection from predation by locating to the center of a group in order to hide behind other members. This study focused on applying the selfish herd theory to shoaling behavior between habitats of varying complexity. Fathead minnows were placed either in a simple or complex environment and shoaling behavior was measured in response to the presence or absence of a predator. The results indicated that habitat complexity and predator presence/absence did not have a significant effect on shoaling behavior. While the data were not significant the results did suggest that in complex environments shoaling behavior is independent of predation risk, which indicates individuals are seeking shelter similar to Hamilton’s selfish herd theory.