Mesozooplankton community composition and structure were examined throughout the D’Entrecasteaux Channel, Huon Estuary and North West Bay, Tasmania, from November 2004 to October 2005, the data represented by this record was collected on the 07/12/2004
The composition of the mesozooplankton community was typical of inshore, temperate marine habitats, with seasonally higher abundance in summer and autumn and lower numbers in winter and spring. Copepods were the largest contributors to total abundance across all seasons and stations, while cladocerans and appendicularians were proportionally abundant in spring and summer. The faecal pellets of these three main groups, along with those of krill and amphipods, also contributed significantly to material recovered from sediment traps. Meroplanktonic larvae of benthic animals showed short-term peaks in abundance and were often absent from the water column for long periods. Spatially, North West Bay and the Channel had a higher representation of typically marine species, including Calanus australis and Labidocera cervi, while truly estuarine species, such as the copepod Gladioferens pectinatus, were more important in the Huon Estuary.
Maintenance and Update Frequency: notPlanned
Statement: Zooplankton were sampled monthly at 4 – 5 sites from November 2004 to October 2005. Five sites were usually sampled, except in cases where weather conditions precluded sampling site 10. A dual Bongo net (mesh size 200 m and mouth diameter 0.75 m) was towed at 3 knots for 3 minutes. The net was deployed to 20 m. After the tow the nets were washed thoroughly with sea water and the catch collected in the closed cod-end. The zooplankton were preserved with 10% formaldehyde and stored until sorted. A flow meter (General Oceanics) attached to the net enabled the determination of the amount of water filtered through the net and thus zooplankton abundance could be expressed on a per m3 basis.
As part of the FRDC project entitled A whole-of-ecosystem assessment of environmental issues for salmonid aquaculture (FRDC number 2004/074; Aquafin CRC project number 4.2(2)), studies of mesozooplankton were initiated in 2004 when it was recognised that they play a critical role in the fate of nutrient cycling within the pelagic environment. The inclusion of zooplankton into the Aquafin CRC study began during Phase 2, with the commencement of regular sampling for mesozooplankton in October 2004 and grazing studies in September 2005. Few studies have examined the distribution of mesozooplankton in temperate Australian estuaries, and there is a particular dearth of studies from recent times. Until this study of the Huon Estuary and D’Entrecasteaux Channel we lacked even rudimentary baseline information concerning zooplankton biodiversity and their distributions in space and time in that region.