Are There Differences in Growth and Condition between Mobile and Resident Cutthroat Trout?

Abstract

There is evidence that actively moving salmonids are of lower condition than the general population, and they are sometimes regarded as inferior to resident fish. However, little information exists on the permanence of this attribute. We used mark–recapture and two-way traps to determine whether there are differences in the condition and growth of mobile and resident Bonneville cutthroat trout Oncorhynchus clarki utah in Beaver Creek, Idaho. Actively moving fish were significantly larger than the general population, and the largest of these mobile fish were in significantly lower condition for a given size. However, mobile fish that were marked and recaptured a year later had regained condition equivalent to that of the general population upon their recapture, and the largest mobile fish had significantly greater condition than fish of equal length in the general population. In contrast, there was no relationship between growth rate and the total distance moved during the 1-year period. These results suggest that the lower condition of actively moving fish does not have permanent effects on future condition or growth in stream-resident cutthroat trout.