Ingestion of artificial diets with different textures as determined by the inert marker ytterbium oxide during culture of early-stage phyllosoma of the spiny lobster, Jasus edwardsii

Instar 1 and 2 Jasus edwardsii (Decapoda; Palinuridae) phyllosoma larvae were fed an artificial diet formulation (based on fish and mussel) consisting of three different gelatin combinations (firm, 4% inclusion; medium, 2% inclusion; and soft, no gelatin). The diet contained ytterbium oxide (Yb2O3; 1% inclusion), an inert heavy metal marker, which was used to confirm diet consumption in instar 1 and 2 phyllosoma. Over a 6-h feeding period, instar 1 phyllosoma showed a preference for the soft and medium diets as opposed to the firm diet, but this effect was not significant with instar 2. The artificial diets remained palatable over the duration of the experiments, suggesting leaching did not influence diet attractiveness. It is suggested that diets comprising softer food items such as microencapsulated pellets or gelatinous formulated diets and pastes are most suitable for early-instar phyllosoma. Furthermore, it is also suggested that Yb2O3 is a potentially useful marker for ongoing quantitative work on diet utilization in lobster larvae.