What is "fallback"?: metrics needed to assess telemetry tag effects on anadromous fish behavior

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Telemetry has allowed researchers to document the upstream migrations of anadromous fish in freshwater. In many anadromous alosine telemetry studies, researchers use downstream movements (“fallback”) as a behavioral field bioassay for adverse tag effects. However, these downstream movements have not been uniformly reported or interpreted. We quantified movement trajectories of radio-tagged anadromous alewives (Alosa pseudoharengus) in the Ipswich River, Massachusetts (USA) and tested blood chemistry of tagged and untagged fish held 24 h. A diverse repertoire of movements was observed, which could be quantified using (a) direction of initial movements, (b) timing, and (c) characteristics of bouts of coupled upstream and downstream movements (e.g., direction, distance, duration, and speed). Because downstream movements of individual fish were almost always made in combination with upstream movements, these should be examined together. Several of the movement patterns described here could fall under the traditional definition of “fallback” but were not necessarily aberrant. Because superficially similar movements could have quite different interpretations, post-tagging trajectories need more precise definitions. The set of metrics we propose here will help quantify tag effects in the field, and provide the basis for a conceptual framework that helps define the complicated behaviors seen in telemetry studies on alewives and other fish in the field.

Study Area

Publication type Article
Publication Subtype Journal Article
Title What is "fallback"?: metrics needed to assess telemetry tag effects on anadromous fish behavior
Series title Hydrobiologia
DOI 10.1007/s10750-009-9917-3
Volume 635
Issue 1
Year Published 2009
Language English
Publisher Springer
Contributing office(s) Coop Res Unit Leetown
Description 13 p.
First page 237
Last page 249
Country United States
State Massachusetts
Other Geospatial Ipswich River, Nemasket River
Online Only (Y/N) N
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details