MEPS 129:127-139 (1995)  -  doi:10.3354/meps129127

Distribution, biomass and community structure of megabenthos of the Gulf of Carpentaria, Australia

Long BG, Poiner IR, Wassenberg TJ

To describe the megabenthos communities in the Gulf of Carpentaria, Australia, beam trawls were taken from a systematic grid of 107 stations sampled during November and December 1990. Over 476500 individuals were collected, weighing over 1700 kg and representing more than 840 species from 150 families. The mean biomass was 15.9 kg trawl-1, the average number of species was 59.8 trawl-1 and the average number of individuals was 4405 trawl-1. The main taxa in terms of biomass were spatangoida (60.5%), porifera (13.7%), zoantharia (7.3%), bivalvia (2.8%), and decapoda (2.8%); they included 12, 102, 10 and 198 species respectively. The megabenthos species were mainly scavengers/carnivores (345), suspension-feeders (331), deposit-feeders (121) and a few herbivores (37). Most species were classed as mobile (496) with lesser numbers classed as sessile species (334). Two deposit-feeding spatangoids accounted for 59% of the biomass but were sampled at only 9 stations. Classification and ordination using species presence or absence data indicated that there were 2 main communities in the Gulf: a community located in predominantly sandy sediments along the eastern and southeastern margins of the Gulf that comprised mainly sessile suspension-feeding sponges, zoantharians, pennatulaceans, bivalve molluscs and ascidians; and a community located in the muddier sediments in the central and western Gulf that comprised mainly deposit-feeding spatangoids and sand dollars. However, sessile suspension-feeders were also found in the central Gulf wherever suitable substrata were present.

Megabenthos . Gulf of Carpentaria . Australia . Community structure

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