Detection Efficiency of a Portable PIT Antenna for Two Small‐Bodied Fishes in a Piedmont Stream

Abstract

AbstractPassive integrated transponder (PIT) tags have been used to infer demography and behavior of lotic fishes, but their application has mostly been limited to salmonids. We studied the efficiency of a portable PIT antenna in a small Piedmont stream (mean width = 2.4 m) in South Carolina by comparing two tag sizes (8‐ and 12‐mm full‐duplex tags) applied to two nongame species (Mottled Sculpin Cottus bairdii and Creek Chub Semotilus atromaculatus). A 285‐m stream reach was blocked off under base flow conditions in September 2016, and 8‐ or 12‐mm PIT tags were implanted in 67 Creek Chub (62–138 mm TL) and 65 Mottled Sculpin (60–88 mm TL). Starting at 1 d after tagging, the study reach was sampled with the portable PIT antenna twice daily for five consecutive days, during which apparent survival of tagged fish was assumed. Generalized linear mixed‐effects models with a logistic link identified that detection efficiency depended on species, tag size, body length, and the species × body length interaction. Mottled Sculpin had detection rates of 56% (8‐mm tags) and 79% (12‐mm tags), with 67% of detections occurring in riffle‐dominated sections, whereas Creek Chub had 3% (8‐mm tags) and 16% (12‐mm tags) detection rates, with 62% of detections occurring in pool‐dominated sections. Detection efficiency decreased with body size in Creek Chub but not in Mottled Sculpin; the observed decrease for Creek Chub was most likely attributable to an ontogenetic habitat shift. The reasonably high detection efficiency of Mottled Sculpin, even with 8‐mm tags, suggested that the portable PIT antenna can be a viable option for some species in small streams, allowing individual‐based approaches to studying small‐bodied species or earlier life stages without the need for repeated physical capture and handling.Received May 13, 2017; accepted October 2, 2017Published online November 10, 2017