Influence of PIT tags on growth and survival of banded sculpin (Cottus carolinae): implications for endangered grotto sculpin (Cottus specus)

Abstract

To make appropriate restoration decisions, fisheries scientists must be knowledgeable about life history, population dynamics, and ecological role of a species of interest. However, acquisition of such information is considerably more challenging for species with low abundance and that occupy difficult to sample habitats. One such species that inhabits areas that are difficult to sample is the recently listed endangered, cave-dwelling grotto sculpin, Cottus specus. To understand more about the grotto sculpin's ecological function and quantify its population demographics, a mark-recapture study is warranted. However, the effects of PIT tagging on grotto sculpin are unknown, so a passive integrated transponder (PIT) tagging study was performed. Banded sculpin, Cottus carolinae, were used as a surrogate for grotto sculpin due to genetic and morphological similarities. Banded sculpin were implanted with 8.3 3 1.4 mm and 12.0 3 2.15 mm PIT tags to determine tag retention rates, growth, and mortality. Our results suggest sculpin species of the genus Cottus implanted with 8.3 3 1.4 mm tags exhibited higher growth, survival, and tag retention rates than those implanted with 12.0 3 2.15 mm tags. To this end, we recommend 8.3 3 1.4 mm PIT tags as a feasible option for tagging adult sculpin (. 60 mm total length) with minimal impacts on growth and mortality.