Evaluation of Artificial Cover Units as a Sampling Technique and Habitat Enhancement for Madtoms in Rivers

• Published in: North American journal of fisheries management Vol. 39; no. 4; pp. 778 - 787
• Main Authors: Cope, W. Robert, Kwak, Thomas J., Black, Tyler R., Pacifici, Krishna
• Format: Journal Article
• Language: English
• Published: 01-08-2019
• ISSN: 0275-5947; 1548-8675
• DOI: 10.1002/nafm.10317

Instream habitat degradation and loss are major threats to freshwater fishes and critical conservation issues among nongame species due to a lack of research and knowledge concerning their habitat requirements. Instream physical cover is an important component of fish habitat, especially for benthic species that require cover for reproduction and shelter from predators. One such species is the Carolina Madtom Noturus furiosus, a small, imperiled, nongame catfish that is endemic to the Neuse and Tar River basins of North Carolina. To enhance understanding of instream cover dynamics, we constructed artificial cover units from terra cotta materials and deployed them in rivers to (1) evaluate whether they could be an effective passive‐sampling technique to estimate detection and occupancy of the Carolina Madtom and (2) determine their potential to enhance habitat in systems where instream cover has been lost. Artificial cover units were deployed at eight sites in the Neuse and Tar River basins, and the units collected 30 Carolina Madtoms at two sites in the Tar River basin. Occupancy modeling estimated a Carolina Madtom detection probability of 0.92 using artificial cover units. Compared to other standardized sampling methods, artificial cover units were an efficient passive‐sampling technique for detecting Carolina Madtoms. Observations also revealed that artificial cover units were occupied by Carolina Madtoms for reproduction. These findings provide an additional means by which natural resource managers can assess the status of this imperiled species via an inexpensive passive‐sampling device that can provide spawning habitat and protection from predators as well as helping to mitigate the effects of instream habitat degradation.