Fish species numbers and surface area of 13 California bays and estuaries and the California continental shelf were positively correlated, and the slope (z) of the log-log regression was 0.21. Mouth width of bays was the only significant variable accounting for variation of species numbers in stepwise multiple regression.
Clustering based on presence or absence of fish species produced a southern and a northern group of bays. A two-way table (bay vs. species) distinguished three broad distributional categories of fish species.
Comparisons of area and species numbers of Chesapeake Bay and King Harbor (southern California) with those of California bays and estuaries supported the view that the present study has relevance for the preservation and management of bay estuarine systems.