Influence of fish presence and removal on woodland pond breeding amphibians

Published source details Towey J.B. (2007) Influence of fish presence and removal on woodland pond breeding amphibians. MSc thesis. Eastern Illinois University.
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This study is summarised as evidence for the following.

	Action	Category
	Brown and black bullheads: Application of a biocide Action Link
	Remove or control fish using rotenone Action Link

Brown and black bullheads: Application of a biocide

A study from 2001-2003 in two ponds in Illinois, USA (Towey 2007) found that rotenone successfully eradicated black bullhead Ameiurus melas, but one pond required two separate doses due to an incomplete initial kill. Rotenone was applied in December 2001 using a motorised and hand-pumped sprayer at concentrations of 7 parts per million or 3.5 parts per million, with dose dependent on apparent fish susceptibility. It was applied from several points along banks to ensure complete coverage. A second application was applied in January 2003 as black bullhead catfish were not eliminated in 2001. Ponds were sampled with wire minnow traps, D-frame nets and visual observations to ensure fish had been eliminated.
Remove or control fish using rotenone

A continuation of a replicated, before-and-after, site comparison study (Mullin, Towey & Szafoni 2004) in 2000–2002 (Towey 2007) found that recruitment of three amphibian species increased after fish elimination using rotenone (see also Walston & Mullin 2007). Recruitment (emerging metamorphs per breeding adult) increased significantly for smallmouth salamanders Ambystoma texanum (from 0 to 1–11), wood frog Rana sylvatica (0 to 1–2) and in one of two ponds American toad Bufo americanus (0 to 15). Recruitment tended to become higher than in two historically fishless ponds (salamanders: 0–1; wood frog: 0–0.5; American toad: 1–10). Numbers of emerging metamorphs increased significantly at experimental ponds for salamanders (0 to 20–205), wood frog (0–2 to 2–15) and American bullfrog Rana catesbeiana (35–42 to 47–50), but not American toad (0–2500 to 100–1700). Numbers of adults captured did not differ with treatment in experimental (before: 2–24; after: 5–44) and fishless ponds (before: 4–68; after: 16–84), apart from American toad which decreased in treatment ponds (before: 20–130; after: 2–80). Amphibians were monitored before (2001) and after (2002) treatment using drift-fencing with pitfall traps (7.5 m apart). Fish were eliminated, apart from bullhead catfish Ameiurus melas in one pond.