Age structure and diel activity of pouting on the Poole Bay artificial reef

Abstract

Predominantly (86·6%) juvenile (<191 mm) pouting Trisopterus luscus formed inactive, nonfeeding schools around artificial reef units in Poole Bay, Dorset, during daylight hours and the position of the schools was related to differing tidal conditions. At current speeds >0·3 m s−1, the pouting congregated close to the reef units, remained low in the water column and maintained position. At current speeds <0·1 m s−1, the schools were more dispersed, further away from reef units and higher in the water column. This tidally‐related behaviour is thought to be related to energy conservation during the daylight hours, when the pouting utilize the lee of reef units during strong tidal currents. Between 15 and 30 min after dusk the majority of pouting left the artificial reef, and returned 45–60 min before dawn. A brief mark‐recapture programme, using 0‐ to 1‐group pouting, confirmed that a proportion of the pouting tagged were present on the artificial reef up to 5 days after marking, suggesting that the site was being used to some extent as a home reef. The nocturnal foraging pattern may be related to the availability of prey species.