Relative stock composition of the Atlantic Coast striped bass population: further analysis

Fourteen variables derive from thirteen morphological characters were used in a stepwise discriminant analysis and a maximum likelihood analysis to estimate the relative contribution of striped bass (Morone saxatilis) stocks from the Hudson River and Chesapeake Bay to the coastal striped bass population. The analyses made use of the spawning-stock data and ocean data collected by Texas Instruments in 1975, although deletions were made to simplify the data to focus on relative contribution north of Chesapeake Bay and on sex and year-class differences. The discriminant function method misclassified approximately 20% of the spawning-stock fish. Errors in estimates of relative conbribution for the spawning stock data were similar for the two methods of analysis. Estimates of relative contribution of the Hudson stock to the coastal population varied considerably among year classes. In particular, the estimated relative contribution for the 1965 year class was between 40 and 50%, while the relative contributions for the 1966, 1968, and 1969 year classes were approximately 10% or less. The relative contribution of males was greater than that of females. The two methods of analysis gave similar estimates of relative contribution of the Hudson stock to the coastal population.