The estuarine fish fauna of the South Alligator River was sampled by beam trawl in both wet and dry seasons. Species richness was greatest in the lower estuary and more species were detected during the wet season. Temporal change in assemblage structure was associated with seasonal variation in discharge concordant with changes in salinity and productivity. Sciaenidae and Engraulidae dominated species richness and abundance overall although the species involved changed between seasons.

Contrasting evolutionary histories may be revealed by mitochondrial and nuclear information. Mitochondrial data suggested that the widespread sooty grunter (Hephaestus fuliginosus) comprised three separate species; however, nuclear information revealed it to be one species only. The phylogeny revealed by mitochondrial data was strongly influenced by historical hybridisation within Hephaestus. Both sources of genetic information indicated a need for a revision of Terapontidae.

Freshwater ecosystems are particularly vulnerable to the increasingly more frequent discharge fluctuations worldwide. Water depth and velocity modifications in streams affect the biota and the processes this biota is involved in. We have shown that the wet subsurface area of the stream can maintain organic matter decomposition rates along those discharge fluctuations, attenuating the effect on the total, reach scale, decomposition.

The use of different structural woody habitats, distance to bank and the interaction between habitats and distance to bank was investigated for Murray cod and trout cod in the mid Murray river, Australia. The study found that both species increased in abundance when structural woody habitat with hollows was present. However, distance to bank also played an important role in abundances, which has important relevance for stream managers.

Knowledge of natural or pre-disturbance instream woody-habitat (IWH) loads is useful to guide such restoration programs; however, such datasets are often unavailable. In the present study, natural IWH loads were mapped along 105 km of undisturbed rivers in south-eastern Australia then modelled for all major Victorian rivers. Distinct IWH-loading trends were noticeable over larger spatial scales. Eastern Victoria showed relatively lower natural IWH loads than did western Victoria.

The effects of operational water level depletion on cladocerans from two lakes bordering a Brazilian run-of-river reservoir were studied. Cladocera showed different responses depending on the connection between lake and reservoir. It is proposed that continuous application of management may lead to a shift in the steady-state equilibrium of the system and loss of diversity.

Oxygen Minimum Zones (OMZs) strongly affect the distribution of megafauna. Bathymetric and seasonal patterns of distribution of decapod crustaceans were studied on the continental slopes off the Mexican Pacific, under the largest OMZ of the world. Bathymetric patterns in community composition were related to the swimming capacity and feeding strategies, and seasonal patterns were related to the community size structure. Oxygen, temperature and food were important drivers of those patterns.

The aim of the present study was to analyse the movement, feeding and case-building behaviours of Phylloicus in the presence of a likely decapod predator, Aegla longirostri. The study demonstrated that caddisfly is able to detect the presence of the predator and modify its activities. It increases its chances of survival by building its case of more resistant materials and by reducing its movement.

The South China Sea (SCS) is an area of extensive coral reef development, yet the understanding on the coral reefs of this region is still low. We analysed the coral communities of Yongle atoll, the biggest atoll in the Xisha Islands, central South China Sea. This baseline investigation highlighted the ecological value of these reefs. They should receive much more scientific and conservation attention.

Poyang Lake is the largest fresh water lake in China. However, nitrogen levels of the lake are increasing because of industrialisation and urbanisation, threatening the stability of the overall ecosystem around the lake areas. Our study indicated that the diversity of ammonia-oxidising bacterial and archaeal communities varied among the different estuaries, and several environmental factors significantly affected those microbial diversities.

The survival and growth of ballast water-mediated phytoplankton communities was assessed, taking into account the specific growth rate, time delay for growth and initial dispersal. Most invasions appeared to fail at the initial dispersal phase. However, they could grow fast enough to overcome the initial dispersal phase if they were dispersed in highly eutrophic waters.

After significant benthic community change following a major flood event, sediment–water fluxes were measured to assess the potential of sediments to support the growth of Lyngbya majuscula. The results show that intermittent periods of oxygen depletion can trigger benthic releases of biologically significant amounts of iron that could support the initiation and growth of L. majuscula blooms.

A laboratory based feeding experiment was conducted to examine how well freshwater macro-invertebrate muscle tissues isotopic ratios reflect the variability of various diet types and diet combinations they are fed. The study provides experimental evidence of individual variability in dietary assimilation. The results help interpret the trophic ecology of individuals feeding on the same or similar diets in the food web.

The aging process in long-lived bivalves could affect metabolic variables. The aim of this study was to analyse possible changes in metabolic and morphometric variables over the lifetime of the freshwater mussel Diplodon chilensis. We propose an age-range (20–30 years old) that would be better suited for bioremediation strategies and would ensure an enhancement of the water and sediment cleansing in Patagonian freshwater bodies.

Geometric morphometrics of marine gastropods allow detecting whether the imposex incidence associated with TBT pollution (neoformation of penis in females) is related to shell-shape variation. This non-destructive technique could help monitor polluted areas without sacrificing animals through the use of gastropod shells as indicators.

The taxonomic status of mussels belonging to the genus Mytilus is explored for several Australian populations. The use of nuclear and mitochondrial genetic markers show that the majority (98.5%) of individuals are M. galloprovincialis. The analysis also revealed that southern and northern hemisphere haplotypes are present, suggesting the introduction of non-native M. galloprovincialis lineages into Australia.

Much of the CO₂ released into the atmosphere from burning fossil fuels is being absorbed by the oceans changing the pH and causing it to become more acidified. As a consequence, marine organisms are likely to exhibit many changes, with shelled organisms such as oysters being particularly susceptible. This research suggests that the local environments from which oysters originate may affect their capacity to respond to ocean acidification.

This paper provides basic information on the age, growth and maturation of S. oualaniensis in the equatorial waters of the ETPO, by using statolith microstructure analysis. The study improves our knowledge of the key life-history and population parameters for S. oualaniensis in the less studied ETPO waters and helps in the assessment and management of this important species.

Estimates of age and growth are important to fish stock assessments aimed at fishery sustainability, but for Pacific cod (Gadus macrocephalus) longevity varies by a factor of 3. One scenario describes a slow-growing fish with a lifespan exceeding 30 years, while the other is fast growing to a maximum age near 10 years. Lead–radium dating revealed that the old-fish scenario is not valid.

This study answers practical questions regarding sticky trap sampling artefacts. We evaluated whether catch rates and sex ratios of Chironomidae were affected by spraying traps with insecticide, placing traps at different heights above ground, and placing traps at different locations within a terrestrial habitat patch. Our results inform whether these variables warrant consideration in future sticky trap studies.

We investigated the photobiology of a symbiotic zoanthid inhabiting different tidal environments: subtidal, intertidal pools and intertidal areas exposed to air during low tide. Results show significant differences in symbiont cell density, pigment content and photochemical efficiency among tidal habitats. These findings suggest that aerial exposure conditions affect photochemical processes but have no dramatic consequences such as bleaching.