Effect of substrate size on sympatric sand darter benthic habitat preferences

Abstract

The western sand darter, Ammocrypta clara, and the eastern sand darter, A. pellucida, are sand-dwelling fishes that have undergone range-wide population declines, presumably owing to habitat loss. Habitat use studies have been conducted for the eastern sand darter, but literature on the western sand darter remains sparse. To evaluate substrate selection and preference, western and eastern sand darters were collected from the Elk River, West Virginia, one of the few remaining rivers where both species occur sympatrically. In the laboratory, individuals were given the choice to bury into five equally available and randomly positioned substrates ranging from fine sand to granule gravel (0.12-4.0 mm). The western sand darter selected for coarse and medium sand, while the eastern sand darter was more of a generalist selecting for fine, medium, and coarse sand. Substrate selection was significantly different (p = 0.02) between species in the same environment, where the western sand darter preferred coarser substrate more often compared to the eastern sand darter. Habitat degradation is often a limiting factor for many species of rare freshwater fish, and results from this study suggest that western and eastern sand darters may respond differently to variations in benthic substrate composition.

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“…Station E1, E2 and E3 were dominated by gravel-mud substrate, sand-gravel mixture and only of sand, respectively. In general, the type of sediment is very characteristic of lake environments (Thompson et al, 2017). Similar observations were observed in Lake Buyo where stations with gravel dominated substrates formed a group that was quite distinct from those consisting mainly of sand (N'Dri et al, 2020).…”

“…The E2 samples showed greater diversity and a more equitable distribution of taxa. These findings could be well correlated with the sediments which offer different habitats depending on the species (Thompson et al, 2017). Station E1 is home to few abundant species such as Tubifex sp.…”

Distribution and Habitat Use of Benthic Fishes in the lower Kanawha River, West Virginia

“…Western Sand Darters, even though known differences in substrate size preference exist (Thompson et al 2017).…”