Comparison between a dart and acoustic tag
Tagging an American shad
Dart tagged American shad
Map of the York River and its tributaries The release point and stations used to acoustically track the tagged American shad.
American Shad Tagging
VIMS has been monitoring American shad abundance since 1998. Acoustic tagging studies have investigated behaviorduring spring spawning migrations in Virginia's rivers.
York River
In 2003, adult shad (29) on theirway to spawning grounds in the Pamunkey and Mattaponi tributaries of the YorkRiver were fitted with acoustic tags. Movements were monitored y threehydrophone stations.
- Almost half of the tagged animals altered their migratory behavior by delaying of abandoning migration.
- Some fish spend time in both tributaries, suggesting the possibility of alternating spawning between rivers.
- Analytical models using tagging data should account for these behaviors.
Olney et al. 2006
James River
In 2005, 98 adult shad were taggedwith acoustic transmitters and released in the lower James River. Movementswere monitored by nine stations covering a 121 km stretch of the river from HogIsland to just upriver of Bosher's Dam.
- Fifty percent of the tagged animals were detected upstream of the lowermost station.
- Migratory movements were significantly related to tidal cycle.
- Shad spent an average of 29 days in the spawning grounds.
- Main residence areas for American shad during the study period were Richmond Deep-water Terminal, Shirley Plantation, and Upper Brandon Plantation.
Aunins 2006
References
Aunins, A.W. 2006. Migratory andspawning behavior of American shad in the James River, Virginia. MS. Thesis.College of William and Mary, Gloucester Point, VA. 99 pp.
Olney, J.E., R.J. Latour, B.E.Watkins, and D.G. Clarke. 2006. Migratory behavior of American shad in the York River, Virginia, with implications for estimating in-river exploitation fromtag recovery data. Transactions of the American Fisheries Society 135:889-896.