Brewster-Geisz and Miller: Management of Carcharhinus plumbeus 



245 



Neonate 



Juvenile Subadult Pregnant adult Resting adult 



Fecundity if) B Growth from stage ( G, ) D Stage residence i P, ) 



Figure 5 



The proportional sensitivities (elasticity) of each stage to fecundity, growth, and stage residence 

 if neonates and pregnant adults are protected (Fj ^=0; F 23 5=0.20). 



too high to maintain the population and must be 

 reduced. At the 1996 SEW, it was determined that 

 reducing F levels by 50% was likely to increase 

 the chances of recovering the large coastal stock 

 (NMFSi). In response to this, NMFS reduced the 

 quota in 1997 for Atlantic large coastal sharks by 

 50% in order to reduce F by BOVc. Assuming that 

 the estimate of F from the SEW is accurate, that a 

 50% quota reduction is equivalent to a 50% decrease 

 in F, and that the reduction in F is equally distrib- 



uted across age classes, we believe our results indi- 

 cate that a 50% quota reduction may not stabilize 

 the stock. Our model predicts that without alter- 

 native management strategies, the population will 

 not begin to recover unless F on sandbar sharks is 

 reduced to below 0.07, requiring a reduction in cur- 

 rent estimates of F of greater than 50%. 



Nursery ground closures and size limits are possi- 

 ble management strategies. These strategies would 

 protect neonates, pregnant adults who are in the 



