82 



Fishery Bulletin 103(1) 



the model not only became less reliable (i.e., RPSS de- 

 creased, especially for females), but also projected higher 

 energy consumption rates. However, the sensitivity anal- 

 ysis points specifically to the parameters (respiration, 

 energy density, female fecundity) that are most influ- 

 ential and deserve attention in laboratory studies. Ad- 

 ditional work is required to better characterize ACT, the 

 activity multiplier, particularly for Sebastes species that 

 are more pelagically oriented. In many bioenergetics 

 models, consumption is a parameter, such that growth, 

 not consumption, can be the model output. Although 

 studies of energy consumption by juvenile black rock- 

 fish (S. melanops) have been undertaken (Boehlert and 

 Yoklavich, 1983), more effort is needed in this area. 



Conclusion 



Although there are limitations to realizing the potential 

 of bioenergetics models in the study of rockfish ecology, 

 those limitations do not overshadow the value of using 

 available information to produce general heuristic models 

 to examine important questions. Such questions include 

 how climate variability affects rockfish consumption pat- 

 terns, reproduction, and predation rates on different prey 

 taxa; how size-selective fishing may influence rockfish 

 consumption patterns; and how rockfish energy demands 

 compare with available prey resources in regions where 

 population rebuilding efforts are proposed or under way. 

 When ultimately coupled with population models, the 

 bioenergetics approach offers a means to clarify the role 

 that rockfish play in their communities. 



Acknowledgments 



Suggestions from Phil Levin, Nick Tolimieri, Daniel 

 Schindler, Rich Zabel, Jim Kitchell, Steve Bartell, Kevin 

 Piner, Tina Wyllie-Echeverria, and two anonymous 

 reviewers greatly improved this manuscript. 



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