How high can a brook trout jump? A laboratory evaluation of brook trout jumping performance
trout, streams, fishways, migration, design, barriers, pool, plunge pool, body length
Journal or Book Title
Transactions of the American Fisheries Society
Quantitative data on how high brook trout (Salvelinus fontinalis) can jump are crucialfor efforts by fisheries managers to exclude brook trout from streams containing native cutthroattrout (Oncorhynchus clarkii subspp.) and to build effective fishways for brook trout migration. Weidentified factors that could influence brook trout jumping ability and demonstrated how thisknowledge could be applied to improve the design of barriers to brook trout migration or fishwaysto facilitate their migration. Our objective was to measure brook trout jumping performance underlaboratory conditions to identify design features for constructing waterfall-type barriers or pooland-weir-type fishways. We used flashboard-type and flume-type adjustable waterfall devices tomeasure brook trout jumping performance at various combinations of vertical or waterfall height(13.5–93.5 cm in 10-cm increments) and plunge pool depth (10–60 cm in 10-cm increments) overa 24-h interval. We tested three size-classes of brook trout: 10–15 cm total length (TL)(mean6SD: 13.09 6 1.67 cm), 15–20 cm (19.30 6 1.19 cm), and 20 cm or more (26.52 6 2.13cm). The 10–15-cm brook trout could jump a 63.5-cm-high waterfall, equivalent to 4.7 times theirbody length, from a 50-cm-deep plunge pool, which was 3.7 times their body length. Larger sizeclasses were capable of jumping 73.5-cm waterfalls, or 2.9–4.0 times their body length, providedthe plunge pools were at least 40 cm deep (.1.6 times their body lengths). Shallow plunge pools(10 cm) prevented brook trout from all size-classes from jumping waterfalls 43.5 cm or more inheight. Small fish were capable of jumping a greater number of body lengths over verticalobstacles than large fish. The data analyses identified vertical height, plunge pool depth, fish totallength, and fish condition as factors important in predicting brook trout jumping performance.