Population viability analysis for the common mudpuppy: Assessing potential impacts of TFM lampricide bycatch

Abstract

Bycatch is one of the leading threats facing aquatic organisms, worldwide. Pesticide bycatch can occur when nontarget species are incidentally killed during chemical application targeting noxious species. The common mudpuppy (Necturus maculosus) is a river-dwelling salamander that is susceptible to bycatch from 3-trifluoromethyl-4-nitrophenol (TFM) applications. However, the long-term consequences of TFM bycatch on mudpuppy populations are not well understood. We used population viability analysis to reveal potential impacts of TFM application on a mudpuppy population in Ohio's Grand River under plausible bycatch scenarios. We found that the population was more sensitive to increased juvenile mortality and rapid declines occurred when both adults and juveniles were impacted at high bycatch rates (≥5% of the population) or more frequent TFM intervals (≥5 years). Our results suggest that continued use of TFM could pose a risk to mudpuppy population persistence if bycatch occurs at moderate to high levels and affects both juveniles and adults. Future TFM use and management decisions should be directed with these potential nontarget impacts in mind.