HEAT INCREMENT OF FEEDING IN STELLER SEA LIONS, EUMETOPIAS-JUBATUS

The heat increment of feeding (HIF) was measured in six captive, juven ile Steller sea lions (Eumetopias jubattus), fed meals of either 2 or 4 kg of herring. HIF was calculated as the post-prandial increase in m etabolism above baseline levels, and was measured using open circuit ( gas) respirometry. It averaged 12.4 +/- 0.9% (SE) of ingested energy i ntake for the 4-kg meal trials, and 9.9 +/- 0.9% for the 2-kg meal siz e. The effect lasted 8-10 hr for the larger meal size. Metabolism peak ed 3.7 hr after feeding, and was 2.13 times higher than baseline level s. For the 2-kg meal size, the effect lasted 6-8 hr, with metabolism p eaking 2.8 hr after ingestion at 1.76 times baseline levels. Our estim ates of HIF for Steller sea lions are at the lower end of estimates fo r terrestrial mammals, and are consistent with estimates for other mar ine mammals. (C) 1997 Elsevier Science Inc.