SURVEY GOAL
The short-term program objectives for the present contract year (1997) include:
- Determine juvenile index values for Alosa (American shad, blueback herring, and alewife) in the Mattaponi and Pamunkey rivers;
- Estimate natural mortality for each species in each river; and
- Examine the relationship between the extant Alosa juvenile indices and the ensuing contributions, as indicated by CPUE, of the respective year-classes to the stocks in the York River Alosa fisheries.
The long-term program objectives are to provide a methodology for establishing a long-term data base of juvenile Alosa indices for the nursery zones of the Mattaponi, Pamunkey, James, and Rappahannock rivers in order to:
- Develop juvenile Alosa indices that are (at the very least) sensitive to good and poor reproductive success.
- Assess the utility of juvenile indices, over a large range in stock sizes, as a surrogate for actual year-class recruitment in stock-recruitment models.
- Determine if species-specific indices exhibit a common pattern of change.
- Determine if patterns of index changes differ among rivers.
- Integrate the year-class assessments in Virginia with those in Maryland to provide a bay-wide estimation of Alosa year-class strength.