Evaluating Handling/Tagging Effects, In-River Residence Time and Post-Spawn Migration
of Anadromous River Herring in the Hudson River, New YorkWes Eakin, Cornell University in cooperation with the New York State Department of Environmental Conservation’s Hudson River Fisheries Unit, New Paltz, NY
Figure 4. Coastal tag returns traversing over approximately 500 miles for
male blueback (Tag ID 8085).
Results
• 23 of 25 tagged fish were detected post release
• Alewives = 0% tagging mortality
• Bluebacks = 17% tagging mortality
• 6 of remaining 23 tagged fish “disappeared” during study
(Figure 2)
• “Disappeared” in areas of heavy harvest from recreational
and commercial fisheries
Acknowledgments
I would like to thank Dewayne Fox, Keith Dunton, the Massachusetts Division of
Marine Fisheries and the Maine Department of Marine Resources for sharing
transmitter detections. I thank the New England Interstate Water Pollution Control
Commission, New York State Department of Environmental Conservation and the
Hudson River Estuary Program for their support during this project.
5/7/2013
5/21/2013
Costal Movement of Blueback Male Tag ID 8085
6/8/2013
7/5/2013
Figure 1. Gastric insertion of acoustic tag.
Conclusions
• This study illustrates the importance of:
• Selecting the appropriate location and timing of tagging
events
• The Atlantic Coastal Telemetry (ACT) Network and its ability
to connect researchers to data that would otherwise be
unavailable
• Recommendations for future studies:
• Upstream migrating anadromous fishes should be tagged
early in their migration and before they reach their spawning
grounds and when possible utilizing multi-year tags
• The use of a secondary external streamer tag is
recommended to identify potential transmitter effects and
assess an individual's overall post-tagging condition during
recapture events
• Researchers conducting acoustic tagging studies along the
Atlantic coast should become members of the ACT Network
• Future tagging studies could identify:
• Additional in-river habitats to protect during spawning
events
• Pre- and post-spawn coastal migration patterns
• Overwintering areas leading to the protection of critical
marine habitats
• Only received coastal tag returns for blueback herring (2
males and 2 females)
• All returns were from the Northeast Atlantic spanning from the
south shore of Long Island, NY to Penobscot Bay, Maine
(Figure 4)
Methods
• Study design consisted of the gastric implantation (Figure 1)
of Vemco® V7-4L tags into 25 river herring (13 Alewives and
12 Bluebacks)
• Majority of both species experienced some degree of fallback
following tagging events (Figure 3)
• Female alewives appeared to be more affected by tagging
events than male alewives or either sex of blueback herring
• Majority experienced fallback without returning or attempting
to return to the spawning grounds (Terminal Fallback)
• May be an artifact of location and timing of tagging events
• Alewives were tagged on the spawning grounds and were
in spawning condition (ripe and flowing)
Figure 2. River herring that “disappeared” during the study. The red
boxes indicate areas of heavy harvest from both commercial and
recreational fishers.
• Mean post-tagging residence times differed significantly
(p<.019) between sexes of alewives
• Females: 14.0 days
• Males: 22.5 days
• Both species exhibited rapid post-spawn emigration behavior
however, bluebacks emigrated at a significantly (p<.0004)
faster rate
• Alewives: 5.7 days
• Bluebacks: 3.3 days
0
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4/16/2013 4/30/2013 5/14/2013 5/28/2013
Riv
er
Kilo
mete
r
Recreational
striped bass
fishery/drift gill
net
commercial
fishery
Fixed gill net
commercial
fishery
Figure 3.Typical post-tagging behaviors of alewives (top) and
bluebacks (bottom). Detections below river kilometer 0 were from
receivers in NY Harbor and along the south shore of Long Island.
Terminal Fallback
Post-tagging residence time
Rap
id E
mig
rati
on Fallback
Initial Tagging Event
Stationary Receiver Federal Dam-Troy, NY
Spawning Grounds
Confluence of Hudson River
Introduction
Study Objectives:
• Identify handling/tagging effects resulting from tagging
events
• Identify gross in-river movements and residence time during
spawning events
• Identify post-spawn coastal migration patterns