768 



Fishery Bulletin 88(4), 1990 



1987 DISTRIBUTION 



Figure 9 



Response surface of the SRL('.\ score function for the northern 

 shrimp survey 1987 length-freciuency distribution. 



Figure 10 



Northern shrimp survey 19,S7 length-frequency distribution (histo- 

 gram) and pattern of SRLCA scores (solid curve) for growth param- 

 eters selected for final evaluation (L,,,, = 33 mm, K = 0.43). 



Table 5 



\'on Bertalanffy growth parameter pairs and SRLCA score 

 (S) for 1988 northern shrimp sui-vey length-frequency distribu- 

 tion: primary and secondary ridge crests. 



L,„, (mm) 



K 



Primary ridge crest 



Secondary ridge crest 



High score parameters of ridge crest, on boundary of ex- 

 jilored space. 



High score parameters of ridge crest, nonboundary max- 

 imum. 

 'Parameters si'lected for final exaluatinii. 



21.5 mm as a single cohort (age 1), with animals 22 mm 

 an(i larger assigned to age 2. Values from the second- 

 ary ridge provided only a slightly improved interpre- 

 tation, with shrimp 11-19.5 mm classified as age 1. 

 20-25 mm as age 2, and >25 mm as age 3. Clearly, 

 the modes in this distribution were not sufficiently 

 distinct to allow a reasonable interpretation using 

 SRLCA (Fig. 12). 



imum at L,,,,- = 43 mm, K = 0.50 to L,,,,- = 49 mm, K = 



0.39, while a secondary ridge ranged from L|„f = 35, 



K = 0.47 to L,„f = 50 mm. K = 0.20 (Table 5, Fig. 11). 



Values from the primary ridge resolved shrimp 1 1- 



Pooled distribution: 1984-88 As with the annual 

 disti'ihutioiis, an exploratory run was made with Lj,,!- 

 values ranging from 20-50 mm, in 1-mm steps, and K 

 values of 0.20-0.50, in 0.01 steps. Two broad regions 



