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However, the bill does not indicate what, if anything, the 

 Secretary is supposed to do with this advice. 



DEFINITIONS 



Current carrying capacity . The numbers of marine mammals 

 supported by habitats prior to human-caused degradation or 

 enhancement may not be known in all cases. We know 

 pre-exploitation numbers for very few stocks of marine mammals. 

 NMFS employs a technique called "back calculation" to estimate 

 these numbers when certain assumptions can be satisfied and the 

 history of removals are known; however, a "back-calculated" 

 estimate is a number based upon current population dynamics. 

 Population models are projected backward in time to estimate the 

 historical number of animals in a population based on current 

 habitat resources. For most stocks, requisite information is not 

 available, and this back calculation cannot be performed. In 

 these instances, we must detect density-dependent mechanisms in 

 operation by using a method such as the dynamic response analysis 

 to assess the population's status with respect to OSP. Neither 

 of these techniques is a true measure of historical numbers; 

 therefore, the definition of "current carrying capacity" proposed 

 in the bill needs to be revised. 



CONCLUSIONS 



The bill we reviewed has drawn from both the NMFS and negotiated 



proposals, and many of the provisions described in the bill are 



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