THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 325 



sion should not be disturbed if nearby but vacant habitat is to be 

 repopulated. 



HABITAT STUDIES 



Studies of abundance of food species should be undertaken where 

 sea otters are abundant and where they are sparse. It has been 

 observed in several areas that sea otters are capable of overutiliz- 

 ing food resources. In a heavily utilized area, for example Am- 

 chitka, underwater exclosures large enough for a diver to enter 

 could be established to evaluate the status of food organisms during 

 a long period in exploited and unexploited areas. During the 

 Amchitka study period (1955-63), it appeared that a large sea 

 otter population was at that time overexploiting its habitat. Body 

 weights of otters were less than those of otters*from sparse popu- 

 lations, and the pelage of Amchitka otters appeared "poor" com- 

 pared to that of otters from a sparse population. Under the con- 

 dition of a depleted habitat, population manipulation may be 

 necessary for a period of years before habitat recovery occurs 

 and animals having optimum body size and pelage are produced. 



TRANSPi^ANT STUDIES 



Capturing, holding, and transporting sea otters is complicated 

 and expensive. The results of experimental transplants are not 

 yet evaluated. Why the transplant of seven healthy, subadult otters 

 to St. Paul Island, Alaska, apparently failed ultimately to survive, 

 in spite of survival after the animals were released, is not known 

 (see Transplant Attempts). Repeated observations of the small 

 Samalga-Umnak population indicate that a small isolated popula- 

 tion grows slowly. Studies and transplant experiments undertaken 

 by the State of Alaska and now in progress should yield valuable 

 information. It appears probable that in certain areas and when 

 a significant number of otters may be moved, transplanting may 

 prove to be a valuable management device. 



