Carp gudgeons are the focus of a theory to explain their biodiversity and life histories, based on developmental plasticity. However, basic data relating to their species boundaries, phylogenetic relationships, life histories and species distributions are not yet clear, have often been misinterpreted and are still in the process of being assembled, making it premature to apply more advanced evolutionary theories to this group.

High-latitude regions are likely to be sensitive to ocean warming, and anemonefishes and their host sea anemones may be a useful indicator group for identifying associated changes. We found that the southern range limits and overwintering of these iconic inhabitants are changing along the eastern coast of Australia. However, the paucity of islands and rocky islets south of our surveys, and host-usage patterns, could constrain future range extensions.

Reproduction is a key biological process that underpins the persistence and maintenance of populations. The present study assessed reproduction in two species of Great Barrier Reef (GBR) sponges: one a brooder and the other a spawner. Temperature was significant in affecting reproduction in these two sponge species. These two species were comparatively more fecund than other sponge species in the region, which may explain their apparent abundance on the GBR.

Range-wide marked declines in population over the past two decades has necessitated a clear strategy for conserving Indus dolphins. Thus, the present study reports a species tolerance threshold towards anthropogenic disturbances and suggests management interventions to conserve the identified havens of dolphins. Ecological constraint of Indus dolphins is considered to be linked to rich biodiversity, therefore assessing the anthropogenic pressure on dolphins may be a surrogate for other threatened components of sympatric freshwater biodiversity.

Summary. Ecosystem modelling has predicted that fishing for western rock lobster in deep water (50–80 m) habitats results in greater production of small-bodied invertivore fish species. To investigate this prediction, a targeted fisheries closure was proposed along the coast of Western Australia. We demonstrate that any changes in fish species are most likely to be detected in the western king wrasse (Coris auricularis), which was found to be abundant across all habitats and sites.

Litterfall and leaf decomposition represent important functional processes in small streams. We investigated how monthly variation in litterfall influences the aquatic community associated with the decomposition of leaf mixtures during 1 year in a tropical stream. We found that litterfall decreased in the period of higher rainfall intensity, and that the litter-breakdown rate was considerably higher in the warmest months.

In this study we investigated how diet composition and intestinal length of the generalist and omnivorous characid fish Bryconamericus iheringii respond to riparian degradation in Brazilian subtropical streams. Open canopies were related to longer intestines and to decreased ingestion of terrestrial plants and invertebrates, concomitant with increased ingestion of filamentous algae, macrophytes and detritus. Riparian degradation may trigger increased intestinal length of generalist fish populations by driving higher relative consumption of indigestible and low-protein food resources.

We have compared dissolved inorganic nitrogen (DIN) release from sediments of rivers and estuaries located at two different hydrologic flow regimes. The DIN releases in the sediment slurry were measured for 48 h at variable salinities, and with constant agitation. Hydrologic forcing on organic matter deposition and salinities had an important role in the sediment slurry release of inorganic nitrogen.

Risk analyses and management techniques are presented for the establishment and effects of two invasive species, smallmouth bass and chain pickerel. With their encroachment on the boundary of Kejimkujik National Park and National Historic Site, there is concern about potential ecological effects. Similar challenges for assessment and mitigation exist elsewhere, and our methods may prove illustrative for researchers and managers working under similar conditions.

Shallow reef-area fish communities of Fernando de Noronha archipelago (north-eastern Brazil) with different levels of environmental protection (no-take MPA and MPA) were compared. Differences in benthic composition, abiotic data and fish-community structure were observed in the comparison between no-take MPA and MPA. A higher diversity, richness, biomass and density of larger fishes were observed for the no-take MPA.

To help juvenile shortfin eels negotiate instream obstacles (e.g. dams), more information is required on ramp angle and what material to line fish ramps with. We found that climbing success decreased with steeper ramps and that climbing success differed between material types. Optimal juvenile shortfin eel ramps would be lined with Miradrain (plastic drainage product) and be set at an angle close to 30°.

The Atlantic needlefish (Strongylura marina) is a coastal epipelagic species inhabiting shallow coastal waters along the western Atlantic coast from Maine to Brazil. We studied the anadromy hypothesis for this species by examining the aggregation of Atlantic needlefish entering and living in Lake Mattamuskeet, the largest natural lake in North Carolina. Although we found no direct evidence of spawning, data compilation suggests that Atlantic needlefish could be using this coastal lake for reproduction.

The aim of the present study was to test the hypothesis that food chain length (FCL) in floodplain systems depends on the planktonic or benthic reliance of predators. Stable isotope analysis was used in eight waterbodies of the Middle Paraná River. The results supported the hypothesis because the planktonic reliance of predators and the relative availability of planktonic resources were correlated with FCL.

Elasmobranch species (juveniles and adults) are distributed in medium and high trophic levels, preying on numerous fish and invertebrates. These species had roles as both predator and prey in four trophic levels of the web, participating in most of the identified roles, and are highly redundant in their functions as prey and mesopredators, but not in their role as top predators.

The recent popularisation of water-based activities is expectedly responsible to increase the odds towards the occurrence of shark bites. Our investigation about the factors underlying shark hazard indicated that shark abundance and shark-bite frequency followed compatible trends off Recife. This study has provided an important insight into the possible biological drivers that regulate the distribution of shark hazard.

Lake MacLeod contains permanently inundated ponds, despite its arid location, because of a subterranean marine link. The present study investigated the effect of biogenic and terrigenous inputs on the physical, sediment and chemical characteristics of these ponds, where the smaller ponds were found to have a persistent marine signature because of their size and faster flushing times. These results have shown that, under certain circumstances, a ‘marine-like’ state can override the typical characteristics of inland water bodies.

High turbidity in reservoirs may negatively affect aquatic ecology and water infrastructure. Although many reservoirs are turbid, the origin and intra- and interannual variability of turbidity is not well understood. To examine the cause and variability of turbidity, we measured the concentration, particle size, organic content and mineralogy of suspended and benthic sediment samples from Lake Dalrymple, a large reservoir in northern dry tropical Queensland.

Stereo baited remote underwater video systems (stereo-BRUVs) were used in this study to investigate the occurrence and size of white sharks (Carcharodon carcharias) in the near-shore environment off Bennett’s Beach, in central New South Wales, Australia. Stereo-BRUVs successfully recorded 34 separate sightings of 22 individual white sharks. This study demonstrates that stereo-BRUVs are a viable, non-destructive method to obtain estimates of the size and presence of white sharks.