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

Predominantly (86.6%) juvenile (<191mm) pouting Trisopterus lucus formed in active, non-feeding schools around artificial reef units in Poole Bay, Dors et, during daylight hours and the position of the schools was related to di ffering tidal conditions. At current speeds >0.3 ms(-1) the pouting congreg ated close to the reef units, remained low in the water column and maintain ed position. At current speeds <0.1 ms(-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 t he daylight hours, when the pouting utilize the lee of reef units during st rong tidal currents. Between 15 and 30 min after dusk the majority of pouti ng left the artificial reef, and returned 45-60 min before dawn. A brief ma rk-recapture programme, using 0- to 1-group pouting, confirmed that a propo rtion of the pouting tagged were present on the artificial reef up to 5 day s 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 availabil ity of prey species. (C) 1999 The Fisheries Society of the British Isles.