MACROBENTHIC ASSEMBLAGES OF THE CONTINENTAL-SHELF AND UPPER SLOPE OFFTHE WEST-COAST OF SOUTH ISLAND, NEW-ZEALAND

Benthic macrofaunal samples were taken at 30 stations on the continent al shelf and upper slope (32-1120 m) off the west coast of South Islan d, New Zealand, southeastern Tasman Sea (c. 41-43 degrees S, 169-172 d egrees E). The area receives a high input (increasing southward) of ri ver-borne sediment, so fine-grained sediments characterise the shelf a nd uppermost slope. Most samples were dominated by polychaetes (mean o f 36% of individuals), with bivalves and amphipods usually the next mo st abundant major taxa (mean of c. 10-11% of individuals). Polychaetes , molluscs and peracarid crustaceans together accounted for c. 77% of species collected. Four main station groups were identified by multiva riate analysis: (1) 4 stations at 32-51 m on silty sand characterised by Sthenelais cf. chathamensis, Nephtys sp., Aglaophamus macroura, Par aprionospio sp., Ampharete kerguelensis, Diplocirrus sp. (all Polychae ta), Austrofusus glans (Gastropoda) and Maorimactra ordinaria (Bivalvi a); (2) 12 stations at 87-297 m on sandy mud characterised by Aglaopha mus verrilli, Lumbrineris ?brevicirra, Paraprionospio coora, Diplocirr us sp. (all Polychaeta), Poroleda lanceolata: (Bivalvia) and Ampelisca chiltoni (Amphipoda); (3) 3 stations at 195-248 m on sand at the nort hern end of the study area where characterising species were Ottonella affinis (free-living Bryozoa) and Chloeia inermis (Polychaeta:); and (4) 10 stations at 477-1120 m on sandy mud where good discriminators w ere Apseudes diversus (Tanaidacea) and Ophiozonella stellamaris (Ophiu roidea). Mean biomass estimates for the four station groups were 79, 4 0, 35, and 6 g wet wt m(-2) respectively. Ordination of polychaete gen era indicated similarities between shallow (< 500 m water depth) west coast samples and directly comparable samples from the Chatham Rise ea st of the South Island, whereas deeper (> 500 m) west coast samples we re more disparate.