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Marking Otoliths and Fin Spines of Juvenile Shortnose Sturgeon with Oxytetracycline and the Effects of Water Temperature during Treatment
Author(s) -
Crumpton Roman L.,
Henne James P.,
Ware Kent M.
Publication year - 2012
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1080/02755947.2012.675951
Subject(s) - fishery , otolith , fish fin , acipenser , juvenile , biology , hatchery , fin , fish <actinopterygii> , sturgeon , zoology , ecology , materials science , composite material
Abstract In order to evaluate a stocking program for shortnose sturgeon Acipenser brevirostrum that uses captive propagation to supplement wild populations, methods are needed to differentiate wild and hatchery‐reared individuals. Recently, methods have been established for marking juvenile shortnose sturgeon in oxytetracycline hydrochloride (OTC) baths, and the marks have been confirmed on both sagittal otoliths and first‐ray pectoral fin spines. However, considerable variability of mark quality has been observed on both structures, and sacrificing the fish for otolith removal is undesirable due to the shortnose sturgeon's endangered status. The objectives of this study were to determine the impact of water temperature during OTC marking on otolith and fin spine mark quality and to determine whether fin spines are as reliable as otoliths for detecting OTC marks. Six groups ( N = 90) of hatchery‐produced shortnose sturgeon fingerlings were exposed to 750‐mg/L OTC baths for 12 h at two temperatures (heated and ambient). After marking was complete, fish were raised for 21 d, then euthanized. Otoliths and fin spines were independently analyzed by two readers, and a mark quality score (0, 1, or 2) was assigned based upon detectability. Fish marked at warmer temperatures (heated treatment) exhibited superior mark quality (mean ± standard error of the mean mark quality = 1.78 ± 0.07) on their otoliths than those marked in the cooler baths (ambient treatment; 1.27 ± 0.09). Similar results were observed for fin spines. Mark quality on fin spines and otoliths was not found to be significantly different. This research demonstrates the ability to chemically mark otoliths and fin spines of juvenile shortnose sturgeon with similar and predictable results. Received July 8, 2011; accepted January 23, 2012