Growth and Prey Selectivity in the Young-of-Year of Brook Trout (Salvelinus fontinalis)

Raymond P. Morgan II^1,*, Donna M. Gates¹, and Matthew J. Kline^1,2

¹Appalachian Laboratory, University of Maryland Center for Environmental Science, 301 Braddock Road, Frostburg, MD 21532-2307 [Retired]. ²Current address - Mount Savage Middle School, 13201 New School Road NW, Mt. Savage, MD 21545. *Corresponding author.

Northeastern Naturalist, Volume 32, Issue 4 (2025): 516–532

First published early online: 5 November 2025

Abstract
We determined young-of-year (YOY) Salvelinus fontinalis (Brook Trout) weight–length relationships, estimated growth of YOY as a function of day-of-year (DOY), and assessed prey selectivity of YOY in order to develop baseline data. Using electrofishing, we systematically sampled YOY Brook Trout (~ monthly) from the 1998 to the 1999 emergence. For YOY, there was a strong relationship of weight to length (r² = 0.99) as well as a strong logarithmic relationship (r² = 0.85) of length to DOY. Over 10 sampling intervals, YOY growth rates varied from 0.0048 g/day to 0.16 g/day (mean = 0.042 g/day). Overall, 23.0% of lengths were outside of the 95% CI, indicating possible effects due to timing of spawning, incubation position in a redd, or quality of ova. Dominant food items were Chironomidae, Copepoda, Collembola, and terrestrials. This information is useful in modeling and assessing regional populations of Brook Trout, but it is uncertain if these baseline data are applicable beyond the narrow range of Brook Trout in the central Appalachians where the study took place.

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