Farm dams: A valuable interim step in small-bodied threatened fish conservation

Abstract

Freshwater fish are facing an extinction crisis on a global scale, with increasing demand for human water consumption driving the regulation and degradation of freshwater ecosystems. Flow regulation especially poses a threat to small-bodied floodplain and creek specialist species through increasing population fragmentation and isolation, loss and degradation of habitats, and interactions with predators and competitors, resulting in reductions in species' range and abundance. Conserving and recovering many small-bodied fish species will likely require translocation from wild habitats to refuge habitats to reduce extinction risk and provide buffers against catastrophic natural events (e.g., drought, bushfires). We assessed the value of semi-artificial farm dams, an abundant feature in the Australian landscape, as interim refugia for the threatened southern pygmy perch Nannoperca australis (Percicthyidae). We compared the relative abundance, population size–structure and body condition of fish introduced (3–4 years prior) into three farm dams with those of three nearby creeks to assess the feasibility of farm dams as a resource to assist small-bodied native fish conservation and recovery. Farm dams had higher abundance of fish, and equivalent size structure and body condition compared with creek populations, highlighting that suitable farm dams are a valuable and underutilized asset for threatened species' conservation globally.