Daily activity pattern of Astropecten aranciacus (Echinodermata: Asteroidea) and two related species under natural conditions

Abstract

Daily activity patterns of Astropecten aranciacus, A. bispinosus and A. jonstoni were investigated by means of SCUBA diving. The three species generally showed two peaks of activity, at dawn and dusk. However, the activity pattern was variable, depending upon site, depth and season. Two populations of A. aranciacus showed only one daily peak at certain times of the year. These peaks were at night in one case, at noon in the other. Light appears to be an important factor governing the activity pattern. © 1978 Biologischen Anstalt Helgoland.