The Sustainable Rivers Audit (SRA) is a systematic assessment of the health of river ecosystems in the Murray–Darling Basin (MDB), Australia. It has similarities to the United States’ Environmental Monitoring and Assessment Program, the European Water Framework Directive and the South African River Health Program, but is designed expressly to represent functional and structural links between ecosystem components, biophysical condition and human interventions in the MDB. Environmental metrics derived from field samples and/or modelling are combined as indicators of condition in five themes (Hydrology, Fish, Macroinvertebrates, Vegetation and Physical Form). Condition indicator ratings are combined using expert-system rules to indicate ecosystem health, underpinned by conceptual models. Reference condition, an estimate of condition had there been no significant human intervention in the landscape, provides a benchmark for comparisons. To illustrate, a synopsis is included of health assessments in 2004–2007. This first audit completed assessments of condition and ecosystem health at the valley scale and in altitudinal zones, and future reports will include trend assessments. SRA river-health assessments are expected to play a key role in future water and catchment management through integration in a Basin Plan being developed by the Murray–Darling Basin Authority for implementation after 2011. For example, there could be links to facilitate monitoring against environmental targets.

Impacts from the logging of Eucalyptus forest on stream habitat, macroinvertebrate abundance and diversity, and fish abundance were surveyed in Tasmania, Australia. Forty-five pairs of sites from 34 streams of 22.5 krn2 catchment area were each sampled once during summer in the period 1990-92. Each site pair consisted of an 'impacted' site downstream of a logging treatment and an upstream or closely matched 'paired control' site. Site pair treatments encompassed two logging methods (cable and conventional) with a range of riparian buffer strip widths (0-50 m) and included unlogged controls. Differences between site pair variables were used as test statistics for the detection of logging impacts. Logging significantly increased riffle sediment, length of open stream, periphytic algal cover, water temperature and snag volume. Logging also significantly decreased riffle macroinvertebrate abundance, particularly of stoneflies and leptophlebiid mayflies, and brown trout abundance. All effects of logging were dependent on buffer strip width and were not significantly affected by coupe slope, soil erodibility or time (over one to five years) since logging. All impacts of logging were significant only at buffer widths of <30 m. Minimum buffer widths for eliminating logging impacts on stream habitats and biota are discussed.

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SUMMARYA more complete study of reproductive behaviour is possible where observations can be made on individuals. This is especially so in a population where each individual has a succession of breeding cycles which are not synchronous with those of other individuals. Continuous records of the breeding of individual barnacles is possible in species which have a membranous base. Individuals may be grown on glass slides and the reproductive condition determined by observations through the base.Reproduction in Elminius modestus takes the form of a succession of breeding cycles or broods, each cycle being initiated by copulation, oviposition and fertilization of the eggs in the mantle cavity. Here the eggs develop, and embryos are eventually liberated through the opercular valves.The time interval occupied by a brood varies both among individuals and with the season of the year. The time of development of the embryos appears to be a function of temperature alone, but the regeneration of the ovary depends upon the nutrition and food supply. When the ovary regenerates rapidly, as in the period of rising temperature, viz. in spring and early summer, another fertilization follows closely upon liberation, but in autumn and winter the ovary may not mature for some time after liberation, with the result that a large proportion of the population do not contain egg masses. In spring and summer the fecundity is probably limited by the rate of development of the embryos; in autumn and winter by nutrition.There is a slight tendency for eggs to remain in the mantle cavity for a longer period during the falling temperatures of autumn and winter than at corresponding rising temperatures in spring and summer.

Endothelial cells lining the circulation are continuously subjected to hemodynamic forces. Because flow is known to influence constriction and relaxation of small arteries and is implicated in the localization of athherosclerotic lesions in large arteries, the role of the endothelium as a "mechanotransducer" of flow-related forces, particularly shear stresses, is of great interest.

Whereas the interannual variability of the climate and fisheries of the Northern Hemisphere has been extensively documented1, very little is known about the interannual variability in the fisheries of the Southern Pacific Region. Recent work in the Norther n Hemisphere has demonstrated the close relations between interan -nual variability in climate, the timing of events in the water column, the structure of food chains and recruitment to both marine and freshwater fisheries2,3. Forty years (1945 −85) of observations at a coastal station (Maria Island, 42°36'S, 148° 16'E) in Tasmania showed strong interannual variability in sea -surface temperatures. Maria Island is close to the region of convergence of the surface currents, on the equatorial side of the Subtrop ical Convergence (STC) water mass boundary4. The spring bloom was often extended by as much as three months in some years. Previous work4 has not offered any explanation for the observed interannual variability and does not show any links with commercial fisheries. Here we explain the reason for the interannual climatic and oceanic vari -ability in Tasmania and show the links between climate and the fisheries.

Movement between habitats in river fish assemblages is often restricted by instream structures such as culverts. The ability of diadromous common jollytail, Galaxias maculatus (Jenyns), and spotted galaxias, Galaxias truttaceus (Val.), to pass upstream through an in situ pipe culvert modified through the installation of baffles was assessed. Spoiler baffles (100 · 70 · 28 or 56 mm) were installed in three spatial arrangements along a 5.5-m section of the pipe, and individual fish passage assessed at three flow velocities (0.35, 0.70 and 1.0 m s )1 ). Common jollytails (43-169 mm fork length, FL) were 10 times more successful in passing when baffles were present than under control conditions (baffles absent). Baffle size did not influence success, which increased with the spatial complexity of the baffle arrangement. Across all velocities, common jollytails (46-132 mm FL) and spotted galaxias (55-190 mm FL) were, respectively, 86 and 73 times more successful with the most complex baffle arrangement (overall 80% success) compared with control conditions (overall 13.5% success). Success for both species decreased at higher velocities under control conditions; however, when baffles were present, this trend persisted only for common jollytails. Installing small spoiler baffles may provide a simple, cost-effective solution to passage problems at culverts. K E Y W O R D S : baffle, culvert, diadromous, fish passage, Galaxias, restoration.

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