WWRC 89-45
Substrate Alteration by Spawning Brook Trout in a Southeastern Wyoming Stream
Abstract
To measure the changes in substrate composition produced by spawning brook trout
Salvelinus fontinalis, we collected 187 freeze-core samples, both before and after spawning, from
egg pockets, inside redds but excluding egg pockets, and outside redds. In the upper strata
of redd-associated samples, we found that the proportions of particles 0.85-1.70, 0.425-0.85, 0.212-0.425,
and less than 0.212 mm in diameter were significantly lower in egg pockets than outside redds,
and the proportions of particles 0.425-0.85, 0.212-0.425, and less than 0.212 mm in diameter
were also lower in egg pockets than in other areas inside redds. Samples collected outside redds
were similar to samples collected before spawning. We observed no significant correlations between
the proportion of fine sediment in samples from outside redds (and presumably the proportion
present before spawning) and the proportion of fine sediment in egg pockets. In vertically stratified
samples, the lower strata contained a greater proportion of the smaller substrate particles than the
upper strata. Spawning brook trout removed fine sediment from the substrate during redd
construction, and this removal was most apparent in the egg pocket. Thus, egg pockets, rather than
entire redds, should be the focus of studies of survival to emergence.
Water Resources Publications List
Water Resources Data System Library |
Water Resources Data System Homepage
