1987/09/01 by Olav T. Oftedal, Sara J. Iverson, Daryl J. Boness · 5 citations
Environmental Science · #Fish Ecology and Management Studies #Marine animal studies overview #Physiological and biochemical adaptations
paper · doi:10.1086/physzool.60.5.30156130
crossref issued 1987/09/01 · crossref published 1987/09/01 · crossref published-print 1987/09/01 · openalex publication_date 1987/09/01 · crossref created 2016/01/07 · crossref deposited 2018/04/07 · openalex created_date 2025/10/10 · crossref indexed 2026/07/30 · openalex updated_date 2026/07/30
Isotope dilution was used to measure milk intake of 43 California sea lion pups on San Nicolas Island, California, from 1982 to 1984. Deuterium concentration was monitored in serial blood samples collected at about 5-day intervals for 3 wk after isotope administration. Estimated milk intakes differed significantly between male (723 ± 31.0 g ․ day⁻¹) and female (609 ± 24.0 g ․ day⁻¹) pups but did not increase from the first to second month postpartum. On a metabolic size basis (weight0.83), gross energy intakes did not differ between male and female pups but did differ between years, apparently as a consequence of the 1983 El Niño. The mean energy intakes (kcal ․ day⁻¹) of sea lion pups in the first (61 · W0.83) and second (308 · W0.83) months were high relative to terrestrial species. Regression of energy intake on growth rate predicted that maintenance energy requirements (kcal ․ day⁻¹) were also high (168 and 252 · W0.83 in the first and second months). The fact that California sea lion pups devote a large proportion of energy to maintenance rather than to growth or to blubber deposition may reflect both the energetic demands of an aquatic environment and limitations in the ability of lactating females to increase the rate of energy transfer to pups.