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Fishery Bulletin 107(2) 
Figure 16 
The broodstock-recruitment relationship of the eastern oyster ( Crassostrea virginica), 
1953-2006, for the natural oyster beds of Delaware Bay, showing low-abundance 
consolidated years (1960-1963 and 1996-2006), low-abundance dispersed years (1987— 
1995), high-abundance consolidated years (1971-1978), high-abundance dispersed 
years (1979-1984), and low-abundance dispersed years (1987-1995). Consolidated 
and dispersed refer to the proportional contribution of the medium-mortality beds 
to total stock abundance as defined by the median value in Figure 5. The solid line 
is the best-fitted Ricker curve (Eq. 4). The dashed line is a second-order polynomial 
fit (see Kraeuter et ah, 2005). The dotted lines represent the 54-yr medians, which 
define the four quadrants (Fig. 10). Graph (A) represents the entire data set and (B) 
represents years with recruitment <6xl0 9 and abundance <5.5xl0 9 . 
is the case. Epizootic mortalities (>0.20 in Fig. 17) 
occurred in four of eight years when the stock was 
dispersed, but only in three of fourteen years when 
consolidated. The second proportion differs signifi- 
cantly from the first (P<0.025). Epizootics are an 
important mechanism leading to stock consolidation, 
and a consolidated stock is resistant to further epi- 
zootic challenge. 
If one considers the relationships of recruitment 
and mortality to broodstock abundance, the high- 
