LO ET. AL.: ESTIMATES OF LARVAL MORTALITY 



Table 2. — Distribution of sampling effort during January through April 1984 by 

 region and month, where p{i) is the proportion of tows for month i and lp{i) = 1 , 

 gijjil '\s the proportion of tows made in region; during month i and Iqijli) = 1, and 

 /■(///^ is the proportion of positive tows for region; during month /and s f(jli)^ 1. 

 The number of tows is.indicated by N, and the positive tows are indicated by n 

 (i.e., those tows which contained anchovy larvae) 



Table 3. — Two parameters describing 

 Gamma distributions' fit to the time be- 

 tween tows minus the constant in each 

 region. Each of these distributions is 

 shifted by the addition of the constant 

 listed. The constant is the minimum time 

 (hours) between two positive tows. 



'Gamma distribution wliere 



g(x)^ 



1 



P(a - 1)! 

 x>0. 



(x/p)- 



'expC-x/p) for 



t 



Figure 5. — Pareto model of larval production where larval mor- 

 tality is assumed to decline with increasing age (Lo 198.5- and 

 1986). Pt is the daily production of larvae at age t; 3 is the mortal- 

 ity coefficient; and t^ is the age at hatch. 



405 



