
TY  - JOUR
A1  - Hill, Nicole A. 
A1  - Blount, Craig 
A1  - Poore, Alistair G. B. 
A1  - Worthington, Duncan 
A1  - Steinberg, Peter D. 
T1  - Grazing effects of the sea urchin <emph type="2">Centrostephanus</emph> <emph type="2">rodgersii</emph> in two contrasting rocky reef habitats: effects of urchin density and its implications for the fishery
JF  - Marine and Freshwater Research
JO  - Mar. Freshwater Res.
Y1  - 2003
VL  - 54
IS  - 6
SP  - 691
EP  - 700
KW  - barrens habitat, fringe habitat, grazing patterns.
UR  - https://doi.org/10.1071/MF03052 
N2  - The sea urchin Centrostephanus rodgersii plays an important role in determining the abundance and composition of benthic macroalgae in New South Wales. Centrostephanus rodgersii is commonly found in areas devoid of foliose algae (termed &#39;barrens habitat&#39;), which abruptly change into areas rich in foliose algae (termed &#39;fringe habitat&#39;). Complementary experiments were used to investigate the impact of C. rodgersii grazing on algal assemblages at a range of densities in the barrens and fringe habitats. Although 33% of the natural density of C. rodgersii maintained barrens areas relatively free of foliose algae, only densities exceeding natural densities within barrens habitat cleared areas dominated by macroalgae. The impact of grazing was not linearly related to density in either habitat, which suggests that both the barrens and fringe habitats are stable and will persist unless there is a dramatic decrease in urchin densities in barrens areas or a large influx into fringe areas. These findings have significant implications for the commercial harvesting of C. rodgersii. They imply that reducing urchin densities in barrens habitats, or translocating urchins from barrens to fringe habitats in order to improve roe quality, will not significantly alter the algal assemblage of either habitat in the short term (less than 3 months). 
ER  -

