Virginia Institute of Marine Science
The 2011 striped bass juvenile abundance index is 27.09 and is significantly higher than the historic average of 7.92. Unlike previous years, the 2011 York River index was the highest among Virginia watersheds with high recruitment in both the Pamunkey and Mattaponi rivers. All individual river JAI values were significantly higher than their respective historic averages except for the Chickahominy River which was not significantly different from its historic average. This suggests a strong year class was produced in the Virginia portion of Chesapeake Bay in 2011. Sampling of auxiliary stations provides greater spatial coverage of the nursery grounds and suggests that juvenile striped bass occupied upstream sites in higher abundances during 2011 compared with these sites historic averages.
Several important changes were incorporated into the 2011 annual report. Samples collected within the currently established sampling season (early-July through mid-September) were used to estimate annual recruitment indices for 1967 – 1973; we omitted samples taken outside the established sampling time frame to improve our ability to compare contemporary indices with those from the late 1960s to early 1970s. In addition, the historic average is now properly calculated as the geometric mean of annual juvenile abundance estimates. Previously, the historic average was simply the mean over all stations sampled over time; the previous method therefore weighted the mean by the number of stations sampled in any given year and because the survey sampled fewer stations prior to 1988, the previous (incorrect) historic average was biased by recent abundance estimates. A juvenile white perch recruitment index has been developed for each major Virginia tributary to Chesapeake Bay.
U.S. Fish and Wildlife Service Sportfish Restoration Project F87R23. Submitted to Virginia Marine Resources Commission, March 2012
Striped bass -- Chesapeake Bay (Md. and Va.); Striped bass fisheries -- Chesapeake Bay (Md. and Va.)
Machut, L. S., & Fabrizio, M. C. (2012) Estimation of juvenile striped bass relative abundance in the Virginia portion of Chesapeake Bay, January 2011-December 2011 : annual progress report. Virginia Institute of Marine Science, College of William and Mary. http://dx.doi.org/doi:10.21220/m2-0jf0-7w22