Laboratory video recordings and underwater visual observations combined to reveal activity rhythm of red-spotted grouper and banded wrasse, and their natural assemblages

摘要: The diel activity rhythm of red-spotted grouper Epinephelus akaara was studied both in captivity and the wild. Behavior solitary (58 to 397 mm total length) a tank video recorded using infrared illuminators under 11L/10D two 1.5-h twilight transition periods, compared that banded wrasse Halichoeres poecilopterus, typical diurnal fish. Underwater observations SCUBA were also conducted their natural habitat reveal behavioral together with visual census adjacent fish crustacean assemblages. Red-spotted showed strong nocturnal regardless body size as opposed strongly wrasse. Activity groupers waters high at dawn dusk, low noon, only few individuals observed night. Visual revealed abundance species richness highest lowest night, intermediate dusk. opposite trend found Absence night may reflect feeding migration away from study area. Alternatively, crepuscular wild is suggested be an adaptation feed on small fishes shift between daytime nighttime rest and/or crustaceans show pattern.