A Reevaluation of the Search Cycle of Planktivorous Arctic GraylingsThymallus arcticus

Publisher Website
Google Scholar
Abstract
Planktivorous arctic grayling, Thymallus arcticus, were previously believed to forage using a cruise strategy, searching for prey while swimming, while other planktivores have been found to search while stationary, a strategy termed "saltatory search." Comparing the predicted components of cruise and saltatory search, we observed that the planktivorous feeding behavior of the grayling was more consistent with the strategy of saltatory search. Although the grayling appear to swim continuously, they actually pause before making turns. Swim speed is reduced with decreased prey detectability, as would be expected of a cruise searcher; however, this behavior is believed to be a result of fin placement and body form constraints. Pause duration, run length, and run turn angle were observed to vary when grayling fed on prey of different sizes, all in a manner consistent only with saltatory search. The relationship between the ability to locate prey and the components of search suggests that the grayling alter the way they search for different prey, possibly as a means of increasing search efficiency.