High species richness in the shallow marine waters of south east Australia

The benthic infauna in 3 areas along 50 km of the coast of Victoria, south-east Australia, was investigated. Grab samples (0.1 m(2)) were collected from a depth range of 11 to 51 m at 12 to 14 sites within each area. Sediments at the sample sites were medium to coarse sand. The distribution of the fauna was related to depth and sediment type. Numbers of individuals and species increased as depth increased and as sediments became more poorly sorted. Species diversity, H-1, increased as sediments became more poorly sorted. Species diversity and evenness, J(1), were greatest at intermediate values for mean grain size. The fauna was extremely species rich. The 104 samples (= a total sample area of 10.4 m(2)) yielded 60 258 individuals and 803 species. Few species were highly abundant and 51% of species collected are apparently undescribed. The data show that species richness may be as high in shallow water as in the deep sea.