Hydrological observations made in January 1984 in the region near Cape Farewell, New Zealand, are described and previously published observations reviewed. It is shown that upwelling depends on the existence of the intermittent Westland Current, and is intensified by an onshore wind. Such a wind induces a fall in sea level near Cape Farewell, and the resulting favourable sea surface slope accelerates deep water over the bathymetric rise inshore of Kahurangi Shoals. The hydraulic response of the thermocline, coupled with a coastal convergence of the bottom Ekman flow, produce a strong upwelling source near Kahurangi Point. M90020

The distribution of temperature, salinity, dissolved inorganic nutrients, and chlorophyll a is described along a transect in Pelorus Sound, as are phytoplankton populations and zooplankton biomass. River water contributed dissolved inorganic nutrients to Pelorus Sound; silicon was a conservative property. Pelorus Sound was a sink, and the open sea a source for nitrate-nitrogen. Havelock Arm and Cook Strait water appeared to be a source for ammonium-nitrogen. Winter cooling at the head of Kenepuru Sound produced highdensity water which sank at the confluence with Pelorus Sound; this is a mechanism (in addition to internal tides) whereby low-salinity high-nutrient water is mixed downwards. Phytoplankton biomass was dominated by diatoms in July 1981. Zooplankton biomass in outer Pelorus Sound in May 1982 was dominated by Amelia aurita. The distribution of chlorophyll a is discussed in relation to the input of river water, inorganic nutrients, and variations in zooplankton grazing pressure. The proposition that more mussel farms would result in long-term food limitation of cultured mussel production is discussed.

Seventeen species of dinoflagellate resting cysts have been recorded for the first time in New Zealand. Isolated from sediments at 93 locations in the Marlborough Sounds, these were Gonyaulax spinifera, G. grindleyi, G. polyedra, G. digitalis, Gonyaulax sp., Protoperidinium subinerme, P. pentagonum, P. conicum, P. oblongum, P. leonis, P. cf punctulatum, P. cf. conicoides, Peridinium stellatum, Peridinium sp., Scrippsiella trochoidea, Polykrikos schwartzii, and Diplopsalis sp. here possible their identities were confirmed by hatching experiments yielding live motile cells. Greatest cyst concentrations and species diversity were found in Kenepuru Sound and Tennyson Inlet. These areas may be more likely to harbour toxic species causing paralytic shellfish poisoning (PSP) or diarrhetic shellfish poisoning (DSP) if these were to appear in the future.

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