How Low Can You Go? Determining a Size Threshold for Implantation of a New Acoustic Transmitter in Age-0 White Sturgeon
2017
Ashton, Neil K. | Liss, Stephanie A. | Walker, Ricardo W. | Brown, Richard S. | Klassen, Cheryl | Backhouse, Stephanie | Bates, Phil | Townsend, Richard L.
Telemetry studies are often used to investigate sturgeon habitat use and movement patterns; however, existing acoustic transmitters are generally too large to implant into age-0 sturgeon without harming the fish. Recent development of a miniaturized acoustic transmitter (cylindrical, 0.7 g in air, 24.2 mm long, 5.0 mm diameter) with up to 365 d battery life has the potential to advance our understanding of age-0 sturgeon ecology in rivers and lakes. Prior to use in field studies, it is essential to conduct experiments evaluating potential adverse transmitter effects on fish. We tested transmitter retention, fish survival, and growth of a broad size range of age-0 white sturgeon (Acipenser transmontanus; 158–277 mm fork length; 26–126 g; 0.6–2.6% transmitter burden) in an 84 d laboratory study, with an ultimate goal of determining a minimum size threshold of sturgeon that can be implanted with this acoustic transmitter. At 84 d post-implantation, transmitter retention and fish survival were 100%. Specific growth rates were reduced at 7 and 14 d post-implantation, resulting in minimum fork length thresholds of 250 and 171 mm, respectively. Juveniles implanted with transmitters regained their growth potential by 28 d post-implantation and no size differences were detected in comparisons with unmarked control fish. This study demonstrates the ability to implant small age-0 sturgeon with high transmitter retention and fish survival, and only minor growth effects. Use of new miniaturized acoustic transmitters may give researchers a means to address questions about young-of-the-year fish recruitment, ecological patterns, and potentially advance conservation management of sturgeon populations.
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