MARINE MAMMAL COMMISSION — Annual Report for 1995 



The Commission noted that the Service's proposed 

 rule provided a population estimate, the calculated 

 sustainable harvest level for the last harvest season 

 and averaged over the last three and five seasons, and 

 an indication, in relative terms, of the population 

 status (i.e., increasing, decreasing, or stable) for each 

 of Canada's 12 polar bear management units. For 

 each population estimate, it also provided an assess- 

 ment of the reliability of the estimate in relative terms 

 (i.e., good, fair, or poor). However, the Commission 

 pointed out, there is no explanation or definition of 

 what constitutes acceptable and uncertain precision or 

 of minimum capture bias or capture bias problems. 

 Therefore, it was not possible to evaluate the reliabili- 

 ty of the assessment ratings. 



The Commission noted that the Service's approach 

 for determining population status assumed that the 

 population estimates are accurate and that population 

 size is affected only or principally by the harvest. In 

 the Commission's opinion, a number of factors, 

 independent of kill levels, may likely affect population 

 size. These include the age and sex structure of the 

 population, ice and denning conditions, prey availabil- 

 ity, and disease. Therefore, the Commission suggest- 

 ed that the final rule should provide a better justifica- 

 tion for using this method for making determinations 

 concerning population status. 



Also, the Commission commented on the produc- 

 tion model used by the Northwest Territories to 

 establish harvest levels, which assumes that polar 

 bears are experiencing maximal recruitment and 

 survival rates. The Commission noted that use of the 

 model will result in very conservative management for 

 populations near carrying capacity, but that popula- 

 tions below their maximum net productivity level will 

 remain depleted under this management scheme. 



The greatest uncertainty regarding the model is the 

 reliability of the population estimates being used. If 

 a population estimate is precise or negatively biased, 

 the formula for calculating harvest levels is reason- 

 able. If, however, an estimate of the population has 

 low precision or is positively biased, use of the 

 formula could lead to overharvesting. To assess the 

 validity of the determinations, quantitative estimates of 

 standard errors and, where possible, identification of 

 likely biases are required. 



The Commission suggested that it would also be 

 useful if the Service were to explain why the use of 

 midpoint or "best" population estimates, rather than 

 minimum population estimates (as used in calculating 

 potential biological removal levels under the 1994 

 amendments to the Marine Mammal Protection Act), 

 is believed to be appropriate. 



Finding on Consistency with CITES - Polar 

 bears are listed on Appendix II of the Convention on 

 International Trade in Endangered Species of Wild 

 Fauna and Flora (CITES). Before a polar bear trophy 

 can be imported into the United States, the appropriate 

 officials in Canada must issue a CITES export permit. 

 Such a permit is issued only after the scientific 

 authority in Canada determines that (1) the export will 

 not be detrimental to the survival of the species and 

 (2) the specimen was legally obtained. In the Com- 

 mission's opinion, the fact that Canada has issued an 

 export permit after making these determinations 

 should provide sufficient evidence that the export and 

 subsequent import are consistent with the Convention. 



Finding on Illegal Trade - The Marine Mammal 

 Protection Act requires the Service, before authorizing 

 the importation of polar bear trophies from Canada, 

 to determine that the export and subsequent import are 

 not likely to contribute to illegal trade in bear parts. 

 In the Commission's opinion, the system for marking 

 and tracking bear trophies in Canada, as described in 

 the Service's Federal Register notice, provides ade- 

 quate assurance that only those bears legally taken in 

 an approved sport hunt will be allowed entry into the 

 United States. The requirement that a CITES permit 

 be obtained from the appropriate Canadian authorities 

 further assures that only those bears legally taken will 

 be exported from Canada. 



The Commission concurred with the Service's 

 assessment that the only potential problem involves 

 trade in gall bladders. Although polar bear gall 

 bladders may not be as desirable as those from other 

 bear species, the number of exports over the years 

 suggests some demand exists. Therefore, the Com- 

 mission agreed with the Service's proposal to elimi- 

 nate the possibility that imports of polar bear trophies 

 into the United States will contribute to illegal trade 

 by requiring hunters to destroy the gall bladder. 

 However, the Commission suggested that it may be 



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