What to expect when you're expecting (larvae): The effects of four algal diets on the development of ​Pisaster ochraceus ​larvae

Abstract

Echinoderm larvae, particularly those of class Asteroidea, are well-studied in a variety of fields ranging from marine ecology to developmental biology. Larvae are useful study organisms in that they are generally easily accessible and can be raised in large numbers at minimal cost. A proper diet is essential for raising larvae to metamorphosis and through the juvenile stage. This study investigates the effects of four algal diets on ​Pisaster ochraceus ​larvae in their bipinnaria stage: ​Rhodomonas sp.,​ ​Dunaliella tertiolecta,​ ​Isochrysis sp.,​ and a combination of the three. Larval size was quantified sixteen days post-fertilization by measuring the maximum larval length, maximum larval width, maximum gut width, and right enterocoel length. Only the maximum larval width proved to be significantly different due to the diet treatments, with the D.tertiolecta​ treatment growing the widest. One replicate of the combined diet treatment yielded larvae with a fused enterocoel, indicating an advanced stage of development, likely due to a decreased larval density as a result of high mortality. Although largely inconclusive, this study offers further insight into the effects of different algal diets on developing echinoderm larvae.