TAG RECOVERIES 



In 1967, four tagged females and two males are identified from checkmarks applied at the 



and two females that had lost their tags were time of tagging, 



collected (table 30). Seals that lose their tags 



Table 30. — Tag recoveries from fur seals collected pelagically 

 by the United States off Washington in 1967 



[Figures in parentheses indicate animals that had lost] 

 tags; they are included in the totals. 



Age 



Year 



of 



tagging 



Tag 

 series 



Seals 

 tagged 



Tag 

 recovery 



a 



Seals collected ir 



each age group 



1/ 



Years 



Number Number Number Number Number 



1/ Table does not include seals born in years when no tagging 

 was done, or year classes from which no tagged seals were taken. 



SIZE 



Mean lengths and weights are given for 

 pregnant and nonpregnant females collected 

 in 1967 in tables C-9 to C-12, and for males 

 in tables C-13 and C-14. Standard deviations 



are shown for samples greater thanfive. Mean 

 lengths and weights of male and female fetuses 

 collected in 1967 are shown by 10-day periods 

 in table C-15. 



REPRODUCTION 



Data on the reproductive condition of females 

 collected at sea (table C-16) are used to relate 

 distribution by reproductive condition to geo- 

 graphic areas, by time, and to determine preg- 

 nancy rates. 



The youngest pregnant females taken in 1967 

 were one multiparous and three primiparous 

 5-year-old seals. 



The Standing Scientific Committee of the 

 North Pacific Fur Seal Commission (1963) has 

 defined the term "missed pregnancy" to mean: 

 "A female may miss pregnancy through failure 

 to ovulate, through failure to be impregnated, 

 or through loss of the blastocyst before im- 

 plantation." 



We define a missed pregnancy as one in 

 which the animal ovulated but did not become 

 pregnant. Animals that have no gross evidence 



of ovulation are classified as nonpregnant ani- 

 mals. The presence of a degenerating corpus 

 luteum in an ovary of a nonpregnant animal 

 indicates ovulation without pregnancy. Preg- 

 nancies that are terminated before implantation 

 may not be detectable several months later. 

 In defining reproductive condition we have no 

 estimate of the amount of error from this 

 cause. 



An increase in the proportion of missed 

 pregnancies would suggest that the population 

 was subjected to increasing stress from some 

 cause. Table 31 shows missed pregnancies in 

 females collected in 1967. 



Table 32 shows the number of female seals 

 (and percentage pregnant) taken in the eastern 

 Pacific Ocean from 1958 to 1967 and table C- 17 

 those taken off Washington in 1967. Pregnancy 



38 



