THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 



225 



independent animals are combined to present an analysis of re- 

 production in the female sea otter. The fundamental histological 

 study on which much of the present analysis of reproductive tracts 

 is based was done by Dr. A. A. Sinha under the direction of Dr. C. 

 H. Conaway (Sinha, Conaway, and Kenyon, 1966). In that study, 

 136 mature tracts taken from 1954 through 1962 were used. Some 

 material from that collection, which was not published in Sinha 

 I et al (1966), is included in the present study. It was kindly given 

 I to me by Dr. Sinha. A study of the histology of the sea otter ovary 

 was recently completed (Sinha and Conaway, 1968). 



The 1963 collections (table 46) added data from different sea- 

 sons which revealed what the earlier material did not: that there 

 is apparently a peak in frequency of births in summer. 



Samples representing certain seasons are small. More specimens 

 ' from summer, fall, and winter are needed before all phases of the 

 reproductive cycle may be based on an adequately large sample. A 

 ; long-continued field study of marked animals and a captive 

 I breeding colony would contribute valuable information on some 

 phases of the reproductive cycle. 



My discussion of various aspects of the reproductive material 

 available is followed by a statistical analysis of this material by 

 Dr. Douglas G. Chapman. 



! REPRODUCTIVE TRACTS 



From 1954 to 1963, reproductive tracts were obtained from 

 animals found dead on beaches, from animals captured (netted) 

 on beaches, and from animals shot during experimental cropping 

 studies. The adult female tracts that were collected are listed in 

 table 46. The four larger collections from 1962 and 1963 (table 46) 

 contribute the most useful material. The smaller collections and 

 individual specimens taken in other years are included where 

 useful in the following analyses. In tables 47 through 51, different 



Table 46. — Adult female sea otter reproductive tracts from Amchitka Island 



[Except those taken in 1960. These were taken in other areas of Alaska] 



Period 



Number 



Remarks 



1954-57- - 



14 



Taken at various seasons. Some from animals found 







dead. Studied by C. H. Conaway and A. A, Sinha. 



Feb.-Apr. 1959 



14 



Most were netted on beaches, several found dead. 







Studied by Conaway and Sinha. 



Jan,-July 1960..... 



4 



Shot (FWS). Studied by Conaway and Sinha. 



Jan .-Feb. 1962 



88 



Shot (ADFG). Studied by Conaway and Sinha. 



Oct. 1962 



14 



Shot (ADFG). Studied by Conaway and Sinha. 



Mar.-Apr. 1963 



125 



Shot (ADFG). Studied by Kenyon. 



July- Aug. 1963 



19 



Shot (ADFG). Studied by Kenyon. 



Total 



278 





