In this study, we focused on developing methods to effectively sample mudpuppies (Necturus maculosus) in the Lamoille River. The sampling area was primarily the 1-km reach immediately below the Peterson Dam. The primary findings were:
• Modified minnow traps set between late fall and early spring were the only effective sampling method. Both adult and large juvenile mudpuppies were captured using this technique. Snorkeling, dip netting, and use of coverboards for collecting eggs did not result in any captures. Electrofishing and seining were not used because the Lamoille River is too deep and turbid for those techniques.
• From late 2008 until May 2010, we captured a total of 167 individual mudpuppies in 173,712 trap hours (7,238 trap days). Of the 167 mudpuppies, 30 were recaptured at least one time within the same winter.
• Capture probability estimates based on modeling were highest when water temperature was between 4 and 6 C. Correspondingly, the highest capture rates occurred in late fall and early spring when water temperature was about 4-6 C. No significant differences were found between mudpuppy capture rates and 1) primary substrate type, 2) secondary substrate type, or 3) water depth.
• Capture probability was positively correlated with the presence of a prey animal (minnow or crayfish) in the trap during winter 2009 and fresh bait during winter 2010. Capture probabilities from trapping peaked at about 0.03, which is similar to the capture probability for salamanders in other studies.
• Age class distribution of non-target mortalities collected following TFM treatment on 1 October 2009 indicate that all age classes are present in the Lamoille River.
• Movement was determined based on time and distance between trap capture events. Mudpuppies moved an average distance of 82 m. The largest movements (>150 m) were in an upstream direction, undertaken by both sexes, and occurred almost entirely in the early spring.
• The sex ratio of trapped mudpuppies changed significantly between the two years, from an even ratio in winter 2009 to male-biased in winter 2010.
• We used Program MARK to estimate the annual population size and apparent monthly survival of mudpuppies across 2 years in the area of 3 140-m trap arrays set over a 1-km reach. The modeled population size estimate for the trap array area was 335 (154 males, 181 females) during winter 2009 and 132 (117 males, 15 females) during winter 2010. Apparent monthly survival estimates during the 2 years for both sexes were about 0.87. All estimates had large 95% confidence intervals.
• Mudpuppy tissue samples (N=600) were collected for genetic analysis from 9 different aquatic systems in the northeast.