Details of the mesoscale variability of the Leeuwin Current are determined from a study of NOAA satellite advanced very high resolution radiometer images over the period 1984–1985 for the area between Shark Bay and Cape Leeuwin on the west coast of Australia. At most times during the selected period there are large wavelike protrusions along the current. During at least three separate periods these appear as a set of three or four roughly equally spaced meanders, or wave crests. Each meander diverts the warm water far offshore of the shelf break, where the core of the southward current is otherwise normally found. Their amplitude generally grows in time, and the anticyclonic motions in the meanders are usually accompanied by cool cyclonic circulations between the meanders. Large meanders are more than 200 km across. Although the flow is unsteady and fronts sometimes translate at speeds of up to 0.8 m s−1, the meanders do not move along the coast and can be followed through the images for 30 to 60 days. These features represent very major diversions to the southward flow in the Leeuwin Current and result in large fluctuations in local current velocity and sea surface temperature. On this scale, the structure of the flow has many features in common with that observed in laboratory experiments with coastal currents driven by steady thermal forcing. Smaller billow structures are also apparent along the strongest temperature fronts in the satellite images.

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Tailor is a key finfish resource in Western Australia and is heavily exploited, but there has been no information either on the location and timing of spawning of the species in these waters or on the subsequent distribution and movements of the larvae. The present study has reviewed the literature to elucidate where tailor typically spawn and in which salinities and water temperatures they are most likely to be found. These data have then been collated with new data on the biology of juvenile and adult tailor in Western Australia, and on the salinities, temperatures and water movements off the coast. This has enabled a hypothesis to be developed delineating where spawning is likely to occur in this region and where the larvae are distributed. It is proposed that spawning occurs in inner-shelf waters between spring and autumn. Eggs and larvae are most likely to be transported to coastal nursery areas by wind-driven northward coastal currents that predominate during the main spawning period.

An airborne infrared scanner was used to map fronts and wakes that occurred at New South Wales headlands and islets. The major front was interpreted as consisting of warm water flowing southward to Point Plomer and then separating from the coast at a 60� angle. Cooler southern water flowed northward to the front and was probably entrained into it. Visual observation from the air showed a colour change and breaking waves at the front. A system of cool northward flowing littoral currents appeared to occur independently of the offshore currents. The relation of the front to the overall East Australian Current system could be interpreted from data obtained by the NOAA-6 satellite and a research vessel at the time.

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