TECNER ET AL.: BIOLOGY AND MANAGEMENT OF RED ABALONES 



FISHING MORTALITY RATE 



Figure 7 .—Continued— For pink abalones, parameters were A' = 0.233, L^ = 186 mm, W^ 

 1,216 g, and J = 0.20 (C) and M = 0.35 (D). 



35% egg production at M = 0.10 and 27% at M = 

 0.15. 



For pink abalones, egg production estimates 

 are shown in Figure 8C and D. At F = 2.0 and 

 the present minimum legal size of 152 mm for 

 recreational harvesters, egg production estimates 

 for M = 0.20 and M = 0.35 were 51% and 75% 

 respectively. 



Simultaneous Analysis 



For red abalones, isoline diagrams illustrating 

 values of SV are shown in Figure 9A and B, using 

 M = 0.10 and M = 0.15 respectively. The curves 

 connecting best combinations of fishing mortality 



and minimum legal size are quite similar. The opti- 

 mum combination occurs at high fishing mortality 

 rates; at a minimum legal size of 188 mm when M 

 = 0.10 and at 182 mm when M = 0.15. Note that 

 when F is greater than 0.3, SV is sensitive to the 

 choice of minimum legal size but not to F; while at 

 low values of F the reverse is true. 



Results for pink abalones are shown in Figure 

 9C and D. With both estimates of M, the opti- 

 mum SV occurs when F = 2.0; however, the 

 best minimum legal size is very sensitive to 

 estimated M. If Af = 0.35, the best minimum 

 legal size is 128 mm; if M = 0.20, the best minimum 

 legal size is 152 mm (the present sport minimum 

 size). 



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