Size, mass, and occurrence of gastroliths in juvenile Steller sea lions (Eumetopias jubatus)

Abstract

Gastroliths, or stones found in the digestive tract of some pinnipeds, were gathered (n = 128) from temporarily captive juvenile Steller sea lions (n = 23, Eumetopias jubatus) at the Alaska SeaLife Center and characterized by their size and mass. Blubber depth and season were significant predictors of gastrolith mass and also positively associated with larger animals. From this, we conclude that they are likely actively ingested for a functional use rather than incidental.