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ESR prepress abstract   -  DOI: https://doi.org/10.3354/esr01086

Suitability of passive integrated transponder (PIT) tags and a new monitoring technique for at-risk madtoms Noturus spp

David A. Schumann*, Michael E. Colvin, Richard L. Campbell, Matthew D. Wagner, Daniel E. Schwarz

*Corresponding author:

ABSTRACT: – Representative indices of population abundance for at-risk species are necessary to inform conservation decision-making. Many madtom species Noturus spp. are considered imperiled; however, the efficacy of frequent monitoring efforts has been questioned due to their cryptic and nocturnal behaviors. We systematically evaluated a madtom monitoring tool by: (1) evaluating the use of small (8 x 2 mm), surgically implanted 125 kHz passive integrated transponder (PIT) tags for frecklebelly madtom Noturus munitus and (2) assessing the effectiveness of an RFID-enhanced artificial cover unit to index madtom abundance. Surgically implanted PIT tags had no apparent influence on madtom survival between 45-110 mm total length and all tags were retained throughout a 21-d laboratory study. In experimental mesocosms, the enhanced cover units confirmed occupancy during nearly all replicates (77.6%), even at extremely low densities (n = 2 madtoms). The enhanced cover units provided representative estimates of madtom relative abundance (F1, 29 = 16.3, p < 0.01, r2 = 0.36); however, catch per unit effort was not significantly associated with previously validated visual observations (F1,16 = 2.7, p = 0.12). Although madtom density and the number detected using the enhanced cover units were correlated, the gear was potentially saturated at relatively high densities (~20 fish per mesocosm) when deploying a single unit. In most cases, occupancy was confirmed within 12 h and nearly half of the individuals were detected within ~72 h. Small PIT tags and RFID-enhanced artificial cover units offer novel opportunities to efficiently describe the ecology and population dynamics of patterned madtoms.