some of these families probably persist into deeper shelf water being joined by some of the upper slope taxa such as the squalidae thus depth too as a proxy for other physicochemical parameters such as temperature salinity etc the shelf communities are probably quite distinct from those on the slope as described generally by longhurst and pauly thus the association of demersal fish communities with particular substratum types has not been demonstrated in the wio other than in a general sense by bianchi and by fennessy in press in a south african study with limited scope