Laboratory Evaluation of Tagging-Related Mortality and Tag Loss in Juvenile Humpback Chub

• Published in: North American journal of fisheries management 2015-02, Vol.35 (1), p.135-140
• Main Authors: Ward, David L, Persons, William R, Young, Kirk L, Stone, Dennis M, Vanhaverbeke, David R, Knight, William K
• Format: Article
• Language: English
• Subjects: fish; Gila cypha; juveniles; mortality; probability; transponders
• ISSN: 1548-8675; 0275-5947; 1548-8675
• DOI: 10.1080/02755947.2014.986345

We quantified tag retention, survival, and growth in juvenile, captive-reared Humpback Chub Gila cypha marked with three different tag types: (1) Biomark 12.5-mm, 134.2-kHz, full duplex PIT tags injected into the body cavity with a 12-gauge needle; (2) Biomark 8.4-mm, 134.2-kHz, full duplex PIT tags injected with a 16-gauge needle; and (3) Northwest Marine Technology visible implant elastomer (VIE) tags injected under the skin with a 29-gauge needle. Estimates of tag loss, tagging-induced mortality, and growth were evaluated for 60 d with each tag type for four different size-groups of fish: 40–49 mm, 50–59 mm, 60–69 mm, and 70–79 mm TL. Total length was a significant predictor of the probability of PIT tag retention and mortality for both 8-mm and 12-mm PIT tags, and the smallest fish had the highest rates of tag loss (12.5–30.0%) and mortality (7.5–20.0%). Humpback Chub of sizes 40–49 mm TL and tagged with VIE tags had no mortality but did have a 17.5% tag loss. Growth rates of all tagged fish were similar to controls. Our data indicate Humpback Chub can be effectively tagged using either 8-mm or 12-mm PIT tags with little tag loss or mortality at sizes as low as 65 mm TL.