Variations in the feeding of 0-group bass Dicentrarchus labrax (L.) in managed realignment areas and saltmarshes in SE England

The diets of 0-group bass Dicentrarchus labrax were investigated in SE England in the Blackwater Estuary: three managed realignment sites at Tollesbury, Abbotts Hall and Orplands; and two established saltmarshes at Tollesbury and Abbotts Hall. In Summer, small 0-group (15–30 mm) bass consumed calanoid and harpacticoid copepods predominantly and left the sites significantly fuller than on entering them (Mann–Whitney, W = 5837, P < 0.001). In Summer, large 0-group (30–59 mm) bass consumed benthic prey, predominantly Carcinus maenas, Nereis spp. and amphipods. These larger bass left Tollesbury managed realignment site, and the established saltmarshes at Tollesbury and Abbotts Hall, significantly fuller than on entry (Mann–Whitney, W = 1116, 372 and 229, respectively, all P < 0.05), unlike at the Abbotts Hall and Orplands managed realignment sites where they had less time to feed. Early site access and soft sediments for macroinvertebrates improved bass feeding opportunities. A wider range of prey was exploited by large 0-group bass in Autumn than in Summer (ANOSIM, R = 0.093, P < 0.05) including organisms associated with the vegetation such as chironomids and fulgoromorphs. Microhabitat differences influence the feeding of this recreationally and commercially important species during one of its most vulnerable life stages, however by Autumn, these site differences are mitigated by the opportunistic feeding of 0-group bass.