Document Type Master's Dissertation Author Kirkman, Stephen Patrick URN etd-12042006-161704 Document Title The seasonal haulout cycle of the declining southern elephant seal, Mirounga Leonina, population at Marion Island Degree MSc (Zoology) Department Zoology and Entomology Supervisor
Advisor Name Title Dr M N Bester Committee Chair Keywords
- elephant seals
Date 1999-10-01 Availability unrestricted AbstractData recorded from annual tagging and regular tag resightings of southern elephant seals at Marion Island, permitted the investigation of temporal variation in the terrestrial haulout cycle of this species, and estimation of participation levels in the little understood resting haulout phase, that could be related to age, sex, and sexual status. Primigravid females moulted later, and were less inclined to rest, than nulligravid females of the same age, but moulted earlier than mature females, among which the mean moulting dates of respective age-classes were practically the same. It is proposed that earlier implantation among primigravid females, as a function of their returning to sea and regaining condition before parous females, resulted in the earlier mean breeding haulout date of primiparous females. The mean haulout dates of breeding and moulting males were negatively and postively correlated with ascending age, respectively. More than half of the surviving individuals of each immature age- and sex-class were observed to haul out to rest, with participation levels generally consistent from year to year, indicating chat the autumn-winter haulout represents more than simple random haulout events. It is suggested that elephant seals are faced with a trade-off between maximising their time spent foraging, and gaining valuable experience at terrestrial functioning, in their immature years.
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Please cite as follows:
Kirkman, SP 1999, The seasonal haulout cycle of the declining southern Elephant Seal, Mirounga Leonina, population at Marion Island, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-12042006-161704/ >
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