614 



Fishery Bulletin 97(3), 1999 



risk. Until we understand these life history stages 

 better, it will be impossible to make quantitatively 

 accurate predictions of the optimal design of any fish- 

 ery management strategy. 



We also need better insight into how fecundity 

 changes with size. Fecundity-size relationships 

 should be fairly easy to measure and can be incorpo- 

 rated into any standard fishery study where adequate 

 numbers of adults are sampled. We would further 

 benefit from estimates of size-specific natural mor- 

 tality. Few natural mortality estimates for coral reef 

 fish species exist in the literature, and most that do 

 are based on highly indirect methods of association. 

 Marine fishery reserves actually offer the potential 

 to generate more accurate predictions of natural 

 mortality because fishing mortality does not confound 

 the attempt in unfished areas. Moreover, despite 

 numerous studies, we still have a poor understand- 

 ing of population regulation and density dependence 

 in coral reef fishes. This understanding is also nec- 

 essary before we can generate accurate quantitative 

 predictions of reserve benefits. 



In contrast to the long list necessary to generate 

 quantitative predictions, our qualitative predictions 

 require additional knowledge in only one key area: 

 fish movement. Because the qualitative predictions 

 were robust across life history patterns, the key to 

 knowing whether a fish species fits our assumptions 

 is the movement of this species as eggs, larvae, and 

 as adults. To some extent, we can skirt this issue 

 because in our model, reserve size was based on pro- 

 portion of coastline rather than actual size. Conse- 

 quently, if we choose the management area to match 

 the scale of fish movement, our model can fit most 

 species. For example, a 20% reserve divided into ar- 

 eas of tens of hectares might ensure that adults of 

 the species we examined here will stay in the area in 

 which they settled while their larvae disperse widely 

 among the reserve and nonreserve areas. In contrast, 

 the management area might have to encompass 

 whole ocean basins for the movement assumptions 

 to fit bluefin tuna (Safina, 1993). Thus, we need to 

 understand the movement dynamics of larvae and 

 adults of a species to know the scales at which it will 

 fit the assumptions of our model. 



From the species that we ran and the resulting 

 qualitative predictions of our model, we can gener- 

 ate a list of testable predictions. We predict that 



1) Reserves will be beneficial for any over- fished 

 population. Populations with low intrinsic growth 

 rates and high fishing mortality stand to benefit 

 the most, as is the case for the majority of reef 

 fisheries in many regions of the world, such as 

 the Caribbean. The location and size of the re- 



serve will also affect reserve benefits. For a fair 

 test of this prediction, reserve should be repre- 

 sentative of typical fish habitat and large enough 

 to contain a viable population of adults. 



2) Although no universal best reserve proportion 

 exists, we predict reserves will enhance fishery pro- 

 ductivity even when they encompass areas much 

 larger than those of current reserve systems. 



3 ) Reserves will reduce variation in catches result- 

 ing from unpredictability in fishing mortality as 

 well as recruitment strength and larval survivor- 

 ship. Such an effect will simplify fishery manage- 

 ment and increase the ability of fishermen to pre- 

 dict future income. 



Acknowledgments 



We gratefully thank the U. S. Agency for Interna- 

 tional Development and its Research Program for 

 Historically Black Colleges and Universities as well 

 as the University of Puerto Rico Sea Grant College 

 Program and the National Research Council's Re- 

 search Associate Program for generous support of the 

 research reported here. We also extend our gratitude 

 to Hilconida Calumpong of the Silliman University 

 Marine Laboratory, who provided inspiration for this 

 work, and to Rebecca Sladek Nowlis, who provided 

 valuable suggestions on drafts of the manuscript. 



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