CAUSES OF SEAL PUP MORTALITY 



Malnutrition, hookworm disease, trauma, 

 multiple hennorrhage-perinatal complex, and 

 microbial infections of various kinds caused 

 most of the pup deaths on three studyareas on 

 St. Paul Island in 1968. These and miscel- 

 laneous causes of death among pups are dis- 

 cussed in this section. 



From 4 July to 15 August 1968, 379 dead 

 pups were collected from catwalks on study 

 areas at Reef and Northeast Point Rookeries 

 (figs. 5 and 6). Of these dead pups, 3Z4 were 

 autopsied and 55 were discarded because of 

 advanced post mortem degeneration. An addi- 

 tional 34 pups that had died on the study areas 

 before we began our research in 1968 were 

 also discarded when the areas were first 



cleared on 4 and 5 July. We know, however, 

 that few pups die from malnutrition before 

 17 July, and we can safely assume that none of 

 the 34 pups died from hookworna disease be- 

 cause the earliest deaths from this cause have 

 been observed about 17 July in past years. 

 Twenty-one dead pups that we discarded after 

 5 July were unsuitable for examimation be- 

 cause of extremely rapid putrefaction, probably 

 preceded by bacterial infection. Emaciated 

 pups deteriorate relatively slow, and hookworm 

 disease can usually be recognized in spite of 

 post mortem change. Thus, we would have 

 discarded few pups that died from these causes. 

 The cause of death was not determined for 12 

 of the 324 pups examined, but we know these 

 animals did not die of malnutrition or hook- 

 worm disease. Therefore, the proportions of 



1-igure 5.— Seal pup mortality study areas 1 and 2, Reef Rookery, St. Paul Island, mid-July 1968. 



Figure 6.~Seal pup mortality study area 3, Northeast Point Rookery, St. Paul Island, mid-July 1968. 



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