ABSTRACT
The two sea star species Astropecten aranciacus and Astropecten bispinosus were expected to aggregate at an artificial Drey patch. This artificial prey patch consisted of an area of 616 m2 on the sandy bottom of Costa Colostrai (SE - Sardinia, Italy). As additional prey the mussel Cerastoderma edule was used, the prey biomass being six time higher than on a control area of the same size. During a period of 20 days the number of the individuals of the two species was recorded daily by means of SCUBA diving.
