Territories and territorial defense in juvenile brook charr, Salvelinus fontinalis (Pisces: Salmonidae)

Publisher Website
Google Scholar
Abstract
The typical territory defended by juvenile brook charr (Salvelinus fontinalis) in a laboratory stream tank was cordate in shape, with the resident stationed at the downstream end facing into the current. Responses by the resident were less aggressive toward intruders at increasing distance from the resident's station. Chases predominated immediately around the station, charges were more frequent further away, and lateral displays were most frequent at the territory perimeter. Defense of the anterior (upstream) area tended to be more aggressive, with equal numbers of charge and chase interactions, while laterally less aggressive and presumably less costly (energetically) charges predominated. These details of territory structure and defense agree with the predictions of an hypothesis of the territory as an economically defensible resource.