ABSTRACT

Somatic growth was compared between Strongylocentrotus droehachiensis on a diet of kelp and kelp covered with the bryozoan, Membranipora membranacea. Efficiency and technique involved in capturing mobile prey was investigated in the laboratory. Urchins were offered live gammarid amphipods and monitored in terms of numbers eaten, as well as capturing technique. Gut contents of urchins collected in the field were analyzed to support laboratory findings. Urchins fed a mixed diet of plant and animal foods grew faster than urchins on a diet of pure algae. S. droehachiensis was effective at capturing and ingesting mobile prey. Gut contents of urchins collected in the field supported laboratory findings that non-algal foods can comprise a significant part of the diet of S. droehachiensis in the Gulf of Maine.