Studies on the zooplankton and hydrology of South-Eastern coastal waters of Tasmania.

The zooplankton and hydrology of the south-eastern coastal waters of Tasmania - Coastal waters off the East Coast, Inshore coastal waters and the Derwent River Estuary are investigated. THE ZOOPLANKTON : SYSTEMATICS Zooplankton species found during the studies are recorded, illustrated, and discussed taxonomically where appropriate. A brief account is given of the distribution of the 71 Pelagic Copepods, 8 Euphausids, 1 Sergestid, 11 Chaetognaths and 7 Pelagic Tunicates. Except for 2 Copepod species which are assigned to a genus, the remainder are positively identified. Amongst the species recorded, 22 Copepods are new to Australian waters whereas 38 Copepods, 1 Euphausid and 2 Chaetognaths are new records for Tasmania. Keys to the genera and species are also given. THE DISTRIBUTION OF ZOOPLANKTON OFF THE EAST COAST AND THEIR VALUE AS BIOLOGICAL INDICATORS Ten Cruises when twelve Stations were usually operated during each Cruise, totalling 89 Stations from August 1971 to May 1973 were made for surface samples off the East Coast. Thirty-five species, mainly based on their preferences for depth or temperature/salinity are selected and analysed from grouping of species and Stations by the computer program DIVINFRE . Six types of water masses involving three water masses characterized by five species-groups such as, (i) Coastal; (ii) mixed Coastal and Sub-tropical; (iii) mixed Coastal and Sub-antarctic; (iv) mixed Sub-tropical and Sub-antarctic; (v) Sub-tropica 1; and, (vi) Sub-antarc tic, are found off eastern Tasmania. iv Some literature contradictions relating to the position of the Sub-tropical Convergence and salinity of Sub-antarctic waters are discussed and it was found that the convergences oscillate along the East Coast with seasons. ZOOPLANKTON AND HYDROLOGY OF INSHORE COASTAL WATERS. Three Stations in inshore waters were operated at monthly intervals for a period of 12 months from August 1971 to July 1972, collecting samples from surface, 10m and 20m depths during day and night. Seasonal diurnal vertical distribution of most of the species and biomass for the 3 Stations are given and discussed. Seasonal zooplankton composition for the Station at the mouth of the Derwent Estuary is given. Relative composition of indicator zooplankton species groups (inshore coastal, coastal and oceanic) are used to determine the influence of estuarine and intrusion of oceanic waters to the region. The possible oceanic waters involved and effects of movement of waters on the accumulation of heavy metals in oysters found in the Derwent Estuary and adjacent waters are mentioned. Such influences are possibly the main factors affecting the seasonal cycles of the zooplankton composition and biomass. ZOOPLANKTON AND HYDROLOGY OF THE DERWENT ESTUARY Collections from two Cruises, on 1st October 1973 and 23rd April 1974 when 10 Stations extending 50 kilometres upstream were operated during each Cruise, are studied. Hydrologically, the region covers from freshwater to marine, 17 zooplankton species representing freshwater, estuarine and marine environment being found. The results are compared with those of previous and similar hydrological and ecological studies.