Comparison of three methods for marking a small floodplain minnow

Evaluation of the movement patterns of small-bodied fish is often hindered by the lack of a suitable long-term mark. We evaluated several techniques for long-term group and individual identification of adult (40–70 mm total length [TL]) Oregon chub (Oregonichthys crameri). We marked Oregon chub with one of two different sized passive integrated transponder (PIT) tags (a 9 × 2.12 mm, 0.067 g PIT tag [PIT-tag] or a 8.4 × 1.4 mm, 0.033 g PIT tag [PICO-tag]), a red visible implant elastomer (VIE) tag, or a freeze brand. We monitored survival, tag retention, and mark quality over 150 days. In addition, we assessed the minimum length and weight thresholds to achieve 80% and 90% survival of PIT-tagged fish. Marking with a freeze brand, PICO-tag, or VIE tag had no effect on survival (P >0.05). In contrast, marking with a PIT-tag was associated with significantly lower (P