Acoustic Tagging of River Herring in the Hudson River: An Unsuccessful Attempt to Waste $10,000

In a 2013 pilot study, we inserted acoustic tags into two species of river herring, alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis). The primary objectives were to (1) identify handling/tagging effects and (2) to assess gross in-river movement and residence time. Our secondary objective was to identify post spawn coastal migration patterns. We gastrically inserted Vemco® V7 acoustic transmitters into 25 river herring (13 alewife and 12 blueback). Despite the small sample size, we collected in-river acoustic data from 23 of the 25 river herring.  The majority of tagged fish exhibited some level of fallback after the handling / tagging event, and with all but female alewives successfully returning to spawning areas.  Both river herring species experienced similar in-river residence times of approximately 2-3 weeks and exited the system 3-6 days post-spawn.  Remarkably, we also collected data on coastal movements of four blueback herring (2 females and 2 males).  Results of this pilot study provide the confidence to repeat this experiment on a larger scale with multi-year tags. This could potentially identify unknown areas to protect during in-river spawning and likely bolster current knowledge of coastal migration patterns for both species.