Handling and Tagging Effects, In‐River Residence Time, and Postspawn Migration of Anadromous River Herring in the Hudson River, New York

Abstract

In a 2013 pilot study, acoustic tags were inserted into two species of river herring, Alewife Alosa pseudoharengus and Blueback Herring Alosa aestivalis. The primary objectives were to identify handling and tagging effects and assess inriver residence time. The secondary objective was to identify postspawn coastal migration patterns. Fish were collected on spawning grounds in the upper portion of the Hudson River, New York. Vemco V7 acoustic transmitters were gastrically inserted into 25 river herring (13 Alewives and 12 Blueback Herring) that were in pre, active, or post spawning conditions. In-river acoustic data were collected from 23 of the 25 river herring. The majority of tagged fish exhibited some level of fallback (downstream migration) after the tagging event, all Blueback Herring and all male Alewives returning to spawning areas. The majority of female Alewives did not return to the spawning area after tagging, and this may be a result of when and where tagging events occurred. Both species of river herring exhibited similar in-river residence times of approximately 2-3 weeks and exited the system 3-6 d after spawning. Information on coastal movements of four Blueback Herring (two females and two males) was also obtained, spanning the south shore of Long Island, New York, to the mouth of Penobscot Bay, Maine. Coastal and in-river tag detections were reported by members of the Atlantic Cooperative Telemetry Network. In conclusion, this experiment can now be repeated with confidence on a larger scale with multiyear tags in order to identify unknown in-river spawning areas, provide information regarding spawning site fidelity, and bolster current knowledge of coastal migration patterns for both species.

A New Paradigm in Alewife Migration: Oscillations between Spawning Grounds and Estuarine Habitats

“…Although these studies (Frank et al. ; Eakin ) did not detect oscillations between the river mouth and the spawning grounds, the reversal behavior is similar to that described here; if such behavior is expressed throughout the species’ range, it could have dramatic implications for how Alewives are studied and managed. The repetitive reversal movements on the spawning grounds can lead to false‐positive identification of fish, specifically at counting sites like culverts and fishways.…”

“…This behavior is likely to exist in other river systems, as evidenced by tagged Alewives in the Ipswich River, Massachusetts (Frank et al. ), and the Hudson River, New York (Eakin ). Frank et al.…”

“…() detected several Alewives that successfully passed a fishway exhibiting reversals within the reconnected habitat of the Ipswich River, a similar‐sized coastal system. In the Hudson River, a portion of tagged Alewives and Blueback Herring Alosa aestivalis labeled as “hesitant” displayed reversals on the spawning grounds that were attributed to tagging effects (Eakin ). Although these studies (Frank et al.…”

“…Tagging and handling effects have been documented in river herring and other anadromous alosines (Frank et al. ; Eakin ) in the form of “fallback” behavior, a posttagging downstream movement of an upstream‐migrating fish. To determine whether there were deleterious effects of tagging, immediate trajectories were examined, and the time of the first downstream migration was measured.…”

“…Acoustic telemetry is a tool that can be used to address the many data gaps in Alewife spawning behavior, but relatively few Alewife telemetry studies exist (Eakin ). From 2012 to 2014, 72 Alewives were acoustically tagged in the Carmans River, a small coastal river with restored passage in Long Island, New York.…”