Survival, Growth, and Tag Retention in Age‐0 Chinook Salmon Implanted with 8‐, 9‐, and 12‐mm PIT Tags

Abstract

The ability to represent a population of migratory juvenile fish with PIT tags becomes difficult when the minimum tagging size is larger than the average size at which fish begin to move downstream. Tags that are smaller (e.g., 8 and 9 mm) than the commonly used 12‐mm PIT tags are currently available, but their effects on survival, growth, and tag retention in small salmonid juveniles have received little study. We evaluated growth, survival, and tag retention in age‐0 Chinook Salmon Oncorhynchus tshawytscha of three size‐groups: 40–49‐mm fish were implanted with 8‐ and 9‐mm tags, and 50–59‐mm and 60–69‐mm fish were implanted with 8‐, 9‐, and 12‐mm tags. Survival 28 d after tagging ranged from 97.8% to 100% across all trials, providing no strong evidence for a fish‐size‐related tagging effect or a tag size effect. No biologically significant effects of tagging on growth in FL (mm/d) or weight (g/d) were observed. Although FL growth in tagged fish was significantly reduced for the 40–49‐mm and 50–59‐mm groups over the first 7 d, growth rates were not different thereafter, and all fish were similar in size by the end of the trials (day 28). Tag retention across all tests ranged from 93% to 99%. We acknowledge that actual implantation of 8‐ or 9‐mm tags into small fish in the field will pose additional challenges (e.g., capture and handling stress) beyond those observed in our laboratory. However, we conclude that experimental use of the smaller tags for small fish in the field is supported by our findings. Received January 9, 2015; accepted May 8, 2015

Science Advancements Key to Increasing Management Value of Life Stage Monitoring Networks for Endangered Sacramento River Winter-Run Chinook Salmon in California

“…A complementary approach to the otolith reconstructions recommended above to assess the lifetime survival and habitat use of SRWRC too small to acoustically tag (Advancement 3), is to tag representative sizes of juveniles with PIT tags throughout the monitoring program or within specific restoration sites. For example, only 8% of the juvenile salmon collected at Knights Landing RST were > 80 mm (the approximate size cutoff for current Juvenile Salmon Acoustic Telemetry System, JSAT, acoustic tags), and 58% met the size threshold for PIT tags (> 40 mm for 8-mm tags; Tiffan et al 2015, see "Notes"; Table 3). Many juvenile SRWRC-sized fish can be sampled for genetic tissue (run ID; Advancement 1) and, because PIT tags are not limited…”

Implanting 8‐mm Passive Integrated Transponder Tags into Small Brook Trout: Effects on Growth and Survival in the Laboratory

“…However, most of those studies examined the potential impacts of tagging larger fish with 12-mm and longer tags. Recent studies with shorter tags (Ouedraogo et al 2014;Tiffan et al 2015) found that approximately 640-mg (wet mass) Nile Tilapia Oreochromis niloticus and 40-49-mm FL Chinook Salmon Oncorhynchus tshawytscha that received 8-mm PIT tags had slightly suppressed growth rates for the first 4 and 7 d but that survival (93.3% and 100%) and tag retention (96.6% at 35 d; 95% at 28 d) were high. Additionally, Ward et al (2015) found no difference in TL between PIT-tagged (8-mm PIT tag) and visible implant elastomer-tagged Humpback Chub Gila cypha as small as 40-49 mm TL.…”

Potential Impacts of PIT Tagging on a Critically Endangered Small‐Bodied Fish: A Trial on the Surrogate Mountain Galaxias

“…; Tiffan et al. ). As technology continues to advance and as PIT tags become smaller, they are increasingly being used on smaller‐bodied fishes.…”

“…; Tiffan et al. ) and as small as 35 mm FL (O'Donnell and Letcher ). Several studies have indicated that juveniles and small‐bodied species (<100 mm TL) belonging to several families, including Cyprinidae, Cottidae, Lotidae, and Percidae, can also be PIT‐tagged with no adverse effects (Baras et al.…”

“…For example, while Chinook Salmon Oncorhynchus tshawytscha as small as 40 mm length to caudal fork (LCF) had over 99% survival when tagged with 9‐mm PIT tags (Tiffan et al. ), comparably high survival rates when using equivalent‐sized tags were observed only in individuals larger than 65 mm TL for the Oregon Chub Oregonichthys crameri (Bangs et al. ); individuals larger than 120 mm TL for the Pacific Lamprey Lampetra tridentata (Mesa et al.…”