FISHERY BULLEITN: VOL. 76, NO. 4 

 c 



2 3 4 5 6 7 



MULTIPLIER OF EFFORT 



2 3 4 5 6 



MULTIPLIER OF EFFORT 



Figure 18. — Yield per recruit, shield per recruit per effort, and average size of catch for hypothetical longline fishery: (a) total yield per 

 recruit, (b) total yield per recruit per effort, (c) yield per recruit per effort in cells 7 1 and 85, (d) yield per recruit per effort in cells 69, 84, 

 and 97, and (e) average size in all squares. 



maximum yield per recruit of about 1.4 kg for 

 uniform recruitment and 2.2 kg for inshore re- 

 cruitment (Figure 19). Catch per recruit per effort 

 was reduced by about 75% under both alterna- 

 tives. The ratio of maximum yield per recruit for a 

 longline fishery to an inshore surface fishery was 

 about 2.7 for inshore recruitment and 3.4 for uni- 

 form recruitment. Average size offish in the catch 

 was about 2 kg higher for uniform recruitment 

 than for inshore recruitment and decreased from 

 16 or 18 kg to 8 or 11 kg with increased fashing 

 effort (Figure 19). 



Simulation of a uniform surface fishery revealed 

 that choice of recruitment model had an insig- 

 nificant effect on yield per recruit, catch per re- 

 cruit per effort, and average size of catch, except 

 that catch per recruit per effort in the nearshore 

 area was relatively high for inshore recruitment 

 (Figure 20). A 75% reduction in F for fish <2.5 yr 

 old had considerable effect on the results. Maxi- 

 mum yield increased from about 5. 1 to 6.9 kg when 

 F was reduced. Both yield curves are dome- 

 shaped. Catch per recruit per effort became rela- 

 tively higher at high levels of effort when F was 

 reduced. As expected, average size was consider- 

 ably higher for reduced F. 



With inshore recruitment, maximum yield per 

 recruit changes from about 2.2 kg for an inshore 

 fishery (Figure 19) to about 5.1 kg for a uniform 



„ 4 

 t 3 



3 



o 



K 2 



>- 



o 



Z3 

 O 



10 

 08 

 06 

 04 

 02 



UNIFORM RECRUITMENT 

 INSHORE RECRUITMENT 



01 23456789 



MULTIPLIER OF EFFORT 



Figure 19. — Yield per recruit, yield per recruit per effort, and 

 average size of catch for hypothetical inshore surface fishery: (a) 

 yield per recruit, (b) yield per recruit per effort, and (c) average 

 size of fish in catch. 



822 



