Marine and Freshwater Research

Inclusion of a social perspective in conservation research in addition to the natural sciences can lead to a more holistic and far-reaching result. Yet, few studies cross borders to be truly multidisciplinary. This perspective addresses previous calls for collaborating authors to share their experiences and considers the existing limitations and ways forward to support multidisciplinary research in conservation science.

CO₂ concentration in freshwater environments is rising, but is also poorly understood, particularly when compared to in marine environments. We sought to test predation success of a common freshwater fish in elevated CO₂, and found that even very high concentrations of CO₂ did not affect predation success. With little research having investigated biological and ecological outcomes of high CO₂ in freshwater, our work suggests a difference in expectations from elevated CO₂ marine biota and systems.

This study provides important limnological data collected in the semi-arid Eastern Cape Karoo region of South Africa before hydraulic fracturing impacts. It was found that depression wetlands and rivers had distinct physicochemical signatures, whereas dams exhibited variable characteristics that were similar to those of either rivers or depression wetlands. These data are important as baseline for long-term monitoring of freshwater ecosystems in the region.

A rapid assessment of paperbark (Melaleuca spp.) decline in permanent freshwater wetlands of the Djelk Indigenous Protected Area, northern Australia, was conducted by scientists and local Aboriginal Rangers. The decline was significantly correlated with poor water quality (high electrical conductivity, turbidity, ammonium), which, in turn, was correlated with feral buffalo activity, suggesting an indirect effect of buffalo on paperbark health.

Hydro-engineering constructions such as groynes change hydromorphology of rivers and affect their aquatic biota. Investigation of odonate fauna from the River Oder, Poland, revealed that groynes increased the abundances, species richness and diversity of dragonflies by creating the mosaics of heterogeneous habitats inhabited by species with particular preferences. The presence of groynes may be essential to the restoration or stabilisation of the populations of certain species and to renaturalisation processes in large rivers.

We evaluated the sensitivity of 12 ecological indicators that characterise fish abundance, body size and trophodynamics with respect to temporal scales. The study explicitly accounted for trophic interactions in the responsiveness and detectability of the indicators, by using a size-spectrum model. The results demonstrated the essential non-linear relationship between EIs and fishing pressures and highlighted potential misinterpretation of indicator temporal dynamics.

Water quality in Lake Roxen, Sweden, is improving, but an expected development towards larger predatory fish is missing. Cormorant diet, recovery of tagged fish, gill-nets surveys and commercial-fishery catches were used to describe the potential effects of cormorant predation. Results indicated that cormorants and fisheries may both be responsible for the lack of recovery. Cormorant predation keeps recruitment high, but the number of fish that reach large sizes remains low.

Microhabitat preferences of caddisfly species in four rivers in north-western Spain were analysed, namely, macrophytes, moss, pebbles and sand. Significant differences in the abundance of seven species (Drusus bolivari, Glossosoma privatum, Larcasia partita, Micrasema longulum, M. servatum, M. gr. moestum and Sericostoma sp.) were found among substrates, confirming that they have substrate preferences.

In many coastal tropical streams, omnivorous shrimp and aquatic insects cause the breakdown of leaf material that falls into the stream. To investigate the relationships between omnivorous shrimp, aquatic insects and leaf breakdown, we excluded either shrimp alone or shrimp and insects from leaf packs by creating electric fields. Leaves broke down fastest when shrimp, but not insects, were excluded, indicating that shrimp are potential predators of insects that are the principal processors of leaves in this stream ecosystem.

Sources of organic matter within the Río de la Plata estuary were investigated by stable isotopic analysis. Upper reaches were highly influenced by terrestrial and freshwater sources, lower reaches were mostly influenced by marine organic matter, and marsh habitats did not supply sediments into the estuary. El Niño events influenced the spatial dynamics of sources within the estuary.

Organisms such as stingrays may vary their habitat selection based on a variety of environmental factors, and their location can indirectly provide insight into the distribution of both their prey and their predators. The purpose of this study was to determine whether tidal stage and diel period affected the movements of Atlantic stingrays (Dasyatis sabina); and we found that they consistently used tidal currents to access their habitat, but only varied habitat selection with diel period in the winter. These movements may affect the probability of a stingray encountering predators, competitors and prey.

This study presents the first detailed information on movement patterns in Australian waters for the poorly known false killer whale (Pseudorca crassidens). We satellite tracked four individuals over ~3–4 months, in coastal waters of the Northern Territory, finding total dispersal distances of ~5000–8000 km over that period. Prior to this study, information deficiencies meant that this species was largely unconsidered in conservation planning and management in Australian coastal waters; the information obtained in this study will allow this deficiency to be remedied.

In this study the causes and rates of blacktip reef shark (Carcharhinus melanopterus) mortality during gill-net capture were assessed. The results demonstrated that juvenile blacktip reef sharks are more likely to die during capture than adults. If populations decrease in the future, fisheries regulations designed to conserve the species should focus on reducing juvenile encounters with gill-nets.

We hypothesised that Phormidium biofilms better use sediments as a nutrient resource than diatoms, and thus Phormidium proliferations would increase with forestry cover in the catchment affecting river ecosystem functioning. Cover of Phormidium increased with the proportion of forestry in the catchment, and river ecosystem metabolism increased with this abundance, suggesting that pine forestry promotes ecological changes along the New Zealand rivers.

Physical processes that determine the spatial distribution of Zostera seagrass in Port Phillip Bay, Australia, were investigated by examining the links between seagrass abundance and broadscale hydrodynamic (waves, currents), physical (light, depth, salinity and temperature) and catchment (nutrient and suspended sediment concentrations) processes. The present study found that the distribution of seagrass meadows is principally constrained by two physical thresholds, namely, wave height or exposure and light. The former excludes seagrasses from colonising wave-exposed coastlines, whereas the latter directly determines the depth profile of seagrasses through its influence on light availability.

This study used underwater cameras to examine how the width of fringing mangrove habitats affected the composition and use patterns of the fish assemblage using mangrove edge habitats in an urbanised estuary on the flooding tide. Both wide and narrow mangroves were found to be viable habitats for estuarine fish.

Jellyfish often carry other animals with them as they swim through coastal waters, yet ecological data on these relationships are scarce. The relationship between a large jellyfish and an associated isopod and anemone was studied over 2 years. The isopod was prevalent on the jellyfish nearly year round, whereas the anemone occurred less often and only between autumn and spring.

Over 30 years of provisioning has led to a predictable aggregation of southern stingrays in Grand Cayman, which is visited by over one million people annually. Despite the economic importance of this aggregation, there had never been a formal assessment of the aggregation. Using previous tagging data and structured censuses, we describe the dynamics of this popular wildlife tourism destination.

The Australian bass is a long-lived native fish. Little is known of the timing of flows important for recruitment of the species in the south of its range. We found recruitment was related to high flows in spring and increasing water temperatures at the time. Lower rainfall and higher temperatures in the region may result in prolonged periods of recruitment failure over the medium to longer term.

Mangrove seedlings planted along an artificial tidal creek at Port Hedland, Australia, showed 18% survival after 3 years. Large numbers of seedlings had recruited naturally into the site. Seedling survival was affected by tidal elevation, but not by creek bank design or erosion protection. Given the right environmental conditions, mangroves will re-establish naturally, although recovery may take >10 years in this semi-arid region.

Because predation risk and food quality are crucial in ecological communities, it is important to understand their combined effects to freshwater invertebrates, namely aquatic insect larvae, which are considered important links in freshwater food webs. Leaf decomposition decreased under predator presence, impairing insect larvae growth, this effect being exacerbated when Eucalyptus globulus, a widespread invasive species, was given as a food source.

During a routine environmental monitoring in the Bahía Blanca Estuary, a temperate and eutrophic ecosystem on the Argentine coast, a parasitic infection was documented on phytoplankton. The host-specific infection on diatoms co-occurred with an extreme precipitation period in the region. Afterwards, the phytoplankton composition and size structure shifted towards dominance of smaller species.

We have developed an approach to assess sea-level rise effects on socio-ecological systems, using Yellow Water wetland on Kakadu National Park as a case study. Sea-level rise will cause profound changes in the Park, but it may also provide an opportunity to bring together Indigenous and non-Indigenous knowledge towards a commonly perceived threat. Strategies that facilitate Indigenous people’s participation in research and monitoring programs are needed to improve understanding of impacts and enhance adaptive capacity.

Distance decay was used as a descriptor of the compositional variation in diatom community similarity over six reservoirs (São Paulo, Brazil). Similarity decreased with distance between habitats and seasons, but the results were not statistically significant for surface sediment assemblages. Diatom communities were controlled more by limited dispersal, probably as a result of the water quality and scale of the study area.

This study has increased our understanding of how isotopes of carbon and nitrogen are incorporated into different tissues of consumers within a freshwater food chain. The study identified that isotopic ratios of these elements vary significantly between tissues, but strong correlations between muscle and shell suggest that the shell can be used as an alternative for muscle in certain circumstances.

This is the first study to investigate mucus as a potential new and useful material in elasmobranch dietary studies using stable isotope analysis. Mucus collected from giant manta rays was indicative of a broader short-term diet during aggregation periods in Ecuador, in comparison to muscle, which suggested long-term diet is more conservative. Both mucus and muscle support that giant manta rays predominately feed on zooplankton at a secondary consumer trophic level.

The influence of environmental variables on shark catch in the bather-protection program along the South African East Coast was investigated for 11 species. Results suggested that measurable, predictable relationships exist between environmental conditions and presence and, consequently, catch of shark species in this program. Understanding these relationships could be useful to mitigate against unwanted catch and to further reduce risk for bathers.

The degradation of freshwater ecosystems is a threat to biodiversity. We evaluated the influence of water quality on the occurrence of a threatened mammal, the Neotropical otter in a river basin under different degradation levels. We found the Neotropical otter to be tolerant to human-altered environments; however, beyond a certain threshold of water-quality degradation, its persistence is at risk.

Invertebrate diversity in subterranean groundwater calcretes of central Western Australia is influenced by periodic rainfall events. After rainfall, taxonomic richness in boreholes increased, as shown by an 11-year survey. Taxonomic groups such as small crustaceans (copepods, amphipods) and dytiscid beetles were the common groups, increasing in numbers during these rainfall periods. An understanding of invertebrate diversity patterns and how they vary temporally will provide information for the management of these groundwater ecosystems.

This study examined two approaches to ageing Pacific spiny dogfish and inter-laboratory variability. Age estimates from dorsal fin spines (historical method) did not agree with age estimates from vertebrae (new method) for older fish, suggesting the new method is not appropriate for fish aged over 10 years. However, inter-laboratory variability was improved using the new method. Results suggest further investigation of the new method is warranted.

The analyses performed showed the following effects of the P. antipodarum invasion on the macroinvertebrate community of a temperate mesotrophic lake: a definite increase in the total macroinvertebrate biomass, a significant increase in the local macroinvertebrate family richness and diversity, a shift in the community composition from crustacean- to gastropod-dominated.

The present study examined the effects of nudibranch predation on behaviour of the geographically restricted and potentially threatened soft coral species Dendronephthya australis. Observations clearly demonstrated the negative impact of predation on feeding ability of this soft coral and suggested that interactions with additional anthropogenic stressors may increase mortality risk for this important habitat-forming species.

The response of different phytoplankton functional approaches to environmental variability over time was evaluated in a large subtropical shallow lake. Dissimilarity in phytoplankton functional composition was related to nutrient and light conditions, even though the sensitivity of the approaches seemed to differ with regard to environmental variability. The functional group composition of phytoplankton sensu Reynolds et al. (https://doi.org/10.1093/plankt/24.5.417) seemed to be the most effective system in describing environmental variability in Lake Mangueira, in southern Brazil, over the long term.

This review is the first on Bythograeidae, documenting the state of our knowledge regarding their taxonomy, evolution, ecology, morphology and physiology (i.e. osmoregulation, oxygen consumption, sulfide and metal detoxification, temperature tolerance). We also report on recent progress in maintaining bythograeids in an artificial ex situ environment.

Warm sea temperatures affected the Great Barrier Reef in the summer of 2016, causing severe coral bleaching in northern and central reef regions. Southern reef areas were thought to escape bleaching; however, herein we report minor coral bleaching around the Keppel Islands (14 sites). Approximately 21% of corals were mildly affected, with Pocillopora and some Acropora appearing sensitive. No mortality was observed. This study contributes to the long-term records of disturbance and recovery dynamics in the Keppel Islands.

The concentration and optical properties of dissolved organic matter (DOM) of lakes provide clues as to the water sources and in-lake microbial and photochemical processes. The present study is the first broad-scale survey of DOM from Patagonian lakes (Chile and Argentina) across a strong west–east precipitation gradient. We conclude that this set of lakes provides a convenient observational system to investigate the effects of contemporary climate change.

Streams under reference conditions are necessary for the evaluation and monitoring of the conservation status of aquatic ecosystems of a region. In this study we demonstrated that a hydrological unit does not constitute a homogeneous entity in terms of environmental variables and biological composition. The results of the study will improve and facilitate the selection of reference sites for biomonitoring programs and for managing Neotropical savanna streams.

Although mailing of live or dead organisms is forbidden in Brazil, smugglers use the postal service to transport aquarium species throughout the country. To assess this illegal practice, confiscations comprising native (including species threatened with extinction) and non-native organisms were performed. Brazilian authorities must intensify package inspections, especially in the south-eastern region, because seizures seem to mitigate the illicit transportation of aquarium species to some extent.

The age and growth of the banded guitarfish (Zapteryx exasperata) from Baja California Sur, Mexico, was estimated for the first time based on growth band counts in its vertebrae. Larger sizes than those reported in the literature were observed for both females (103-cm total length, TL) and males (92 cm TL). Similarly, females lived longer than males (22.6 v. 19.6 years respectively).

Mangroves are one of the most widely distributed types of plants that grow along the coast of Australia. Low winter temperatures and frost are thought to limit the stature and productivity of mangroves in Victoria. Because air and water temperatures will increase markedly over coming decades, it is likely that Victorian mangroves will be among the first plant communities to be noticeably affected by climate change in coastal south-eastern Australia.

Scarcity of iron limits phytoplankton growth in approximately two-thirds of the world’s oceans. Hydrothermal plumes have recently gained recognition as a long-range source of iron to the deep oceans that, importantly, may also affect surface ocean phytoplankton growth in some regions. This review brings into focus current understanding of hydrothermal systems and their contribution to the global oceanic iron budget.

In this study we investigated the behaviour of cyanobacteria by determining phycocyanin and chlorophyll concentrations using spectroradiometric and fluorometric data. The spectral analyses could only detect phycocyanin at higher concentrations. For lower concentrations, phycocyanin was detected from fluorometric measurements. Therefore, remote sensing complemented by fluorometric analysis seems an effective method for monitoring cyanobacteria in Brazilian inland waters.

Climate change modified the spatial distribution of two sympatric Mediterranean fishes. Does this change have indirect effects on trophic niches and trophic interactions between the two species of fish? The two species have different trophic niches and do not interact for food, regardless of forcing of climate change.

The Cooloola Patterned Fens are a unique wetland in south-eastern Queensland and are potentially at risk from water extraction for the nearby town. Statistical analysis of regional water-chemistry data was used to determine the groundwater source that the ecosystem depends on. The fens were found to use perched aquifer water, whereas local creeks are connected to the deeper regional aquifer.

Amphidromous fish live and spawn in streams, but are widely believed to have an oceanic larval period, resulting in wide dispersal and connective populations. In this study we show that when an alternative larval habitat (i.e. a lake or wetland) is present, freshwater larval rearing is the dominant process sustaining many populations. The retention of larvae in lakes has implications for the dispersal, connectivity and management of amphidromous fish.

The present study examined the dry-season meso-habitat use by the amphidromous shrimp species, Macrobrachium spinipes, in northern Australia. We found that habitat use changed considerably first, with ontogeny, and, second, with the annual colonisation of habitats with algae and macrophytes as the dry season progressed. The study has provided significant insights into the changes in use of key riverine habitats throughout the dry season by an ecologically important species

In a recent paper in Marine and Freshwater Research, Nichols et al. called for a reinvestment in national-scale bioassessment in Australia. We agree that the absence of national-scale bioassessment impedes the ability to detect slow-acting impacts such as climate and land-use change. We argue that a reinvigorated national program should go beyond bioassessment and assess river resilience, including the social and ecological parameters that influence river health.

Hydrodynamics drive the export of estuarine-derived primary production and nutrients to adjacent, less-productive offshore waters. The present study quantified estuary-to-coast fluxes of detritus and nutrients by sampling the water at the mouth of a small temperate estuary. These types of studies are important to determine the ecosystem services provided by temperate estuaries.

Conventional river models typically ignore the effects of groundwater-storage change on river flow, and, hence, predicted declines in river low flows during drought periods are likely to be compromised. The present study undertakes statistical analysis of low flows in the Namoi River, and highlights implications for river modelling more broadly. The results showed the importance of adopting models that explicitly account for groundwater processes when modelling such river systems.

A wild lemon shark (Negaprion brevirostris) was observed to expel an ingested foreign object through its body wall, over a minimum period of 435 days. We observed this lemon shark at a recreational diving feeding site off the coast of Jupiter (FL, USA) on 12 occasions between 6 December 2014 and 14 December 2016. Following expulsion, we observed this lemon shark recovered and in apparent healthy condition.

Atmospheric nuclear testing added the radioisotope caesium-137 to the global environment. We sampled depressional wetland soils across three regions of the United States (Southeast, Atlantic Coast, and Midwest) and quantified accumulated sediment, carbon, nitrogen and phosphorus compounds in wetland soil since ‘peak caesium’ deposition in 1964. Substantial accumulation occurred, with only phosphorus differing by region. Depressional wetland management is, thus, important for landscape-scale sediment, nutrient and carbon dynamics.

Reduced turbulence and aeration can affect stream ecosystems, but their effects can differ from the surface to subsurface habitats, and depend, among other things, on sediment size and the availability of organic matter (OM). A microcosm experiment showed that lack of aeration reduced OM consumption, especially on the surface, and sediment size caused differences in performance between the two invertebrate species studied, namely mayfly (Habroleptoides) and stonefly (Capnioneura).

The Asian water monitor is widespread on the island of Sri Lanka. The present study was a 7-month survey within a 5-km stretch at an urban riverscape in Sri Lanka. The most monitor sightings were made in aquatic habitats. Given variable sighting frequencies of distinct life history stages across different major habitat types, it is likely that there is substantial age-structured niche partitioning among these monitors.

Reducing invasion rates of aquatic species is an important conservation concern. In this study we investigated whether zooplankton assemblages in ponds subject to fish releases from aquaculture facilities are affected by ‘hitchhiking’ species from these farms, and found differences between ponds with and without carp releases. Management is required to prevent unintentional introductions of invertebrate from aquaculture facilities from which fish are released.

Zooplankton play an important role in transferring energy from primary producers to upper trophic levels. By investigating epipelagic mesozooplankton community and hydrographic features of the Dongsha Atoll, we found that temporal pattern of mesozooplankton community is likely to be more dependent on physical variable than on primary production due to the semi-enclosed topography. Abundant decapod larvae and fish eggs confirmed the importance of the pelagic–benthic coupling in the tropical reef ecosystem.

Tissue metal concentrations are used as indicators of metal contamination. In some marine snails, high background copper concentrations can mask small but biologically significant copper uptake. The present study used isotopically enriched copper to measure copper uptake in a marine snail. Biomarkers were used to measure the copper-induced stress response. Measuring isotopically enriched copper allowed links to be established among exposure, uptake and response.

We analysed the taxonomic and trophic diversities of Mayfly in ponds and streams of floodplains in the Cerrado and Amazon–Cerrado transition. The largest diversities occurred in the transition between biomes, which can be related to the ecotone tension. There was no significant difference between the two types of ecosystems, probably because of the high water connectivity during the rainy season.

Field surveys revealed that newly recruited giant sea anemones grew rapidly, then slowed their growth and shrank near the end of their lifespans, at rates that depended on their fish symbionts. Populations were highly dynamic, with estimated turnover times of only 3–5 years. These anemones appeared to be short lived relative to their fish symbionts, leading to species-specific implications for their conservation management.

The blind side of the brill (Colistium guntheri) is usually white without any coloured patterns. The discovered specimen from Manukau harbour, Auckland, was unusual and showed broad melanic patches running mainly at the base of the dorsal and anal fins on its blind side. Such a case has not been reported from any of the flatfish species collected from New Zealand before and, therefore, it is an interesting and important record for fisheries sector in general.

Mobile acoustic camera transects were used to determine the distribution of fish within a small estuary. Fish distribution was found to be linked to water depth for two size classes. This study demonstrates the usefulness of conducting mobile acoustic camera transects in shallow estuaries to determine distribution and relative abundance of fishes.

In all, 976 fish from 133 species, collected in Moreton Bay, Queensland, were examined for the presence of larval trypanorhynch cestodes. Nine species of cestodes were found, providing new host and geographical records. Comparison of the cestode fauna with that of coral reef fish indicated that the fauna in Moreton Bay was less diverse but was dominated by similar species.

The seagrass Zostera muelleri is abundant in estuaries in Australia and is under pressure from coastal developments. We studied sulfide intrusion in the seagrass along a gradient of anthropogenic impact in Wallis Lake estuary and found high sulfide intrusion when inputs of organic matter from phytoplankton were high. The seagrass was, however, efficient in oxidizing the sediments, which may explain lack of negative effect of sulfide intrusion.

We employed a partitioning framework to investigate the contribution of turnover and nestedness to β diversity patterns in non-arboreal amphibians from southern Pantanal ecoregion. In the grasslands, β diversity is driven essentially by turnover. In the savannas, both turnover and nestedness contributed similarly to β diversity. Species turnover was associated with altitude and factors that induce spatial patterns.

The present study investigated the effects of exposure to high CO₂ levels on the early development of three commercially important fish species. The results reveal reduced hatching rates under high CO₂ levels, but suggest species-specific responses and different ways of coping with this stressor during early development. Future studies will investigate the long-term effects of high CO₂ throughout the life cycle.

Environmental drivers affect the entanglements of humpback whales (Megaptera novaeangliae) and common dolphins (Delphinus delphis) in the gill-nets of the Gold Coast Shark Control Program. Entanglements primarily occurred during calm sea state conditions, with M. novaeangliae entanglements highest in September and D. delphis highest in June. Other significant variables influencing entanglements also include rainfall, spring tides and the East Australian Current.

This study examined the mortality rate of silvers eels passing through a small hydropower station in a river from the southern Baltic area using acoustic telemetry. During the experiment, no direct mortality occurred as a result of passage through the turbine; however, a few individuals exhibited migration delay as a result of injuries or passage trauma.

This study investigated the feasibility of using an artificial neural network (ANN) as a tool to accurately forecast cyanobacteria counts and microcystin concentrations in the Dau Tieng Reservoir through environmental parameters. The sensitivity analyses conducted with the ANNs identified critical variables (i.e. total nitrogen and temperature) that have the most positive and negative effects respectively affecting cyanobacteria counts and microcystin concentrations.

Waterfalls have unique physical characteristics and harbour specialised macroinvertebrate communities, but have been the subject of few ecological studies. The present study investigated the trophic structure of waterfall assemblages. Methods included stable-isotope analysis (δ¹³C and δ¹⁵N of leaf litter and periphyton) and gut-content analysis of the most abundant macroinvertebrates. Data indicated that despite scouring velocities, waterfalls support animals with a range of diets, based on grazing or scraping, filter feeding and predation.

The effect of regrowth riparian vegetation on soil nutrients and river channels was investigated in south-east Queensland, Australia. River sections with regrowth vegetation had greater channel width complexity. In addition, degraded river sections, without regrowth vegetation, had higher soil nutrient concentrations. This study indicates that the restoration of regrowth riparian vegetation may require ongoing management to maximise nutrient retention potential.

The present study investigated benthic mollusc assemblages from Antarctica. Evidence was found of different trophic assemblages (most probably linked to the sedimentary matrix where these communities settle), as well as differences between bivalves and gastropods with regard to limiting factors: bivalves appear to be more sensitive to temperature, but gastropods are more sensitive to depth. This should be taken into account when considering effects on benthic fauna associated with climatic change and global warming.

Benthic trophic status of Uruguayan estuaries was evaluated by the biochemical composition of sedimentary organic matter (SOM). Morphological and hydrodynamic differences between habitats explained site-to-site variation in eutrophic conditions in the open or closed estuaries and meso-oligotrophic conditions in open estuaries. In autumn, the dominance of aged and more degraded SOM (low nutritional value) was evident, whereas in spring fresh and more labile SOM (high nutritional value) prevailed.

The reproductive biology of the blue shark (Prionace glauca) in the western North Pacific Ocean was investigated to contribute to future stock assessments. Results suggested that the North Pacific blue sharks has a higher productivity than previously thought, on the basis of larger fecundity and annual reproductive cycle.

We evaluated the contribution of insects to the diet of Amazonian stream fish in Pará, Brazil. The fish and insect fauna of 10 streams were sampled in the Tapajós National Forest. The fish consumed a diversity range of nutrients, confirming that most are generalists. The results of this study reinforce the importance of riparian forest in the feeding ecology of stream fish.

Otolith-based body size back-calculation with young Pacific bluefin tuna (Thunnus orientalis) from the north-western Pacific was used to test the hypothesis of growth-dependent survival and to identify critical developmental stages for survival. The results suggest that only the larvae with fast, steady growth successfully become juveniles and, hence, that growth-dependent survival in the larval stage is critical for recruitment.

We modelled the distribution of a fish assemblage around a large artificial reef, using a rapid drop-camera survey method. We found that the reef greatly influenced fish abundance, but the effect was very localised, such that reef bottom type was a more powerful predictor than distance to reef. The drop-camera method showed promise for quantifying the fine-scale distribution of fish assemblages.

In this study, the krill assemblages off the north-west marine bioregion were investigated and related to the physical, biological and biogeochemical properties of the water column. Twenty-five krill species were identified, including new records for Australian waters. Assemblages were primarily structured by depth, but mean seawater density, dissolved oxygen, fluorescence and mesozooplankton abundance also significantly explained some of the variation in krill assemblages.

Communities living underground in cave streams are entirely dependent on movement of energy and nutrients from the surface. As a result, changes to the surface environments will alter the underground communities. We examined the differences between stream communities under agricultural and forested catchments to determine what effect agricultural activities have on underground communities in New Zealand.

The present study evaluated the population genetic structure of sandfish (Holothuria scabra) within Papua New Guinea (PNG) and more broadly northern Australia. Microsatellite-based population genetic analyses were used to determine partitioning of genetic diversity within and among subpopulations. The level of genetic substructuring among all populations sampled was low, although significant. Most of these differences were driven by distinctness of the Australian populations from those in PNG, whereby results indicated that PNG populations exhibited a panmictic stock structure.

A lionfish invasion could be dramatic for the Mediterranean Sea. Investigating sea users’ knowledge showed that the species is widely distributed along Lebanese coasts and allowed evaluating the potential of local communities to respond to this threat. Results stress the importance of civil awareness to face an issue of environmental concern in a complex socio-ecological system, such as the eastern Mediterranean.

Analysis of nitrate and ammonium concentrations at different spatiotemporal scales is important because these represent the main nutrient loadings to aquatic ecosystems in agricultural basins. Herein we provide a framework for evaluating the variation in nitrate and ammonium concentrations and their relationships with environmental and anthropogenic variables. At the landscape level, the agricultural area affected nitrate and urban affected area ammonium, whereas at the basin level road density affected both.

Macroinvertebrates are widely used for monitoring freshwater ecosystems. The use of DNA barcodes to identify macroinvertebrates has the potential to change how routine biomonitoring is conducted. Herein we discuss the need for DNA barcodes of freshwater macroinvertebrates and compare barcoding efforts within Australia with those globally. Further, we present an initial effort towards a national DNA barcode library of Australian macroinvertebrates.

Tropical seagrass meadows are commonly recognised as important habitats for juvenile fish, whereas tropical seaweed beds have rarely been investigated. The present study illustrates that the abundance of juvenile fish in seaweed beds can surpass that in seagrass meadows, also when it comes to coral reef-associated species and species used by fisheries, which underscores the need to widen the view of the tropical seascape.

Carp is the most common cyprinid species in Turkey and accounts for approximately one-fifth of total inland water aquaculture production. Carp production in Turkey has decreased in recent years. This article identifies population structure, growth and reproduction characteristics of carp in Hirfanli Dam. Changes in the carp population in this area are compared with those reported in previous studies worldwide.

The spatial distribution of phytoplankton was investigated in Pacific western boundary currents. Traditional approaches (size-fractionated chlorophyll-a and microscopic analyses) combined with single-cell analysis (using a flow cytometer) were used to analyse the whole range of phytoplankton community in the Pacific western boundary currents.

Deep sections of river channels present challenges for surveying riverine fish assemblages based on conventional techniques. Herein we demonstrate an application of underwater video for detecting multiple species of fish in shallow and deep sections of two tropical rivers and conclude that where water clarity is favourable, video provides one means by which assemblages can be investigated across the entire depth profile.

We investigated phytoplankton community structure and environmental factors of Lake Nansihu, the largest freshwater lake in north China. Seasonal fluctuations in phytoplankton community composition were recorded and their driving environmental factors were identified based canonical correspondence analysis. The results of this study will be useful in guaranteeing the water quality and ecological security of lakes in temperate regions.

The study describes the first reported instance of severe, sudden and widespread dieback of mangrove vegetation associated with an extreme weather event. Although moisture stress is largely considered the cause, the combination of relevant likely stress factors, each linked to the same extreme fluctuation in the Southern Oscillation Index, elude to a plausible connection with global climate change.

Here, we show the effect of invasive species across whole ecological communities and the important functions they perform. By investigating sites with and without the invasive fish species Gambusia holbrooki, we found significant differences in pelagic and benthic community composition, and size distribution of zooplankton. Reductions in leaf-litter breakdown, an energy source for lake ecosystems, in invaded sites were also found.

Nitrogen and carbon isotope compositions in biological tissues are effective tracers of the source and fate of nutrients in coastal ecosystems. This study traced the time-integrated dispersion and biological uptake of sewage-derived nutrients along a tropical macro-tidal creek by measuring the isotope compositions in mangrove leaves and gastropod snail tissues.

The first Australian workshop addressing climate concerns for fisheries was held in 1991. The nine workshop recommendations are still relevant today, and while monitoring efforts have been significant and knowledge has accumulated rapidly, implementation of management and policy responses have lagged. To successfully respond to the climate change challenges to Australian fisheries over the next decade increased support for climate-ready fishery policies and programs is needed.

We sought to determine whether a montane freshwater crayfish limited to a southern Queensland (Australian) catchment experiences thermal stress under natural conditions. Laboratory-conditioned crayfish exhibited evidence of thermal stress at higher temperatures. When applied to field populations, crayfish at the lowest altitude of sampling exhibited evidence of a thermal stressor. It appears those crayfish at the lower altitude experience higher levels of environmental stress than those populating cooler, higher habitat.

In southern New Zealand, in-stream nitrogen (N) and dissolved organic carbon (DOC) concentrations increased with increasing agricultural development in high-country grassland watersheds. Weather and soil conditions mediated the amount of DOC transferred from soils into streams, but did not influence the relationship between land use and N or phosphorus (P) when stream flow rates were low to moderate.

The magpie goose is an iconic tropical species highly valued as a conservation asset and by Aboriginal people as a cultural resource. Their spatial and temporal dynamics in the Kakadu Region of Northern Australia are characterised at seasonal and decadal time scales using long-term aerial survey data. The customary harvesting practices of geese and their eggs in the region show that their cultural value extends beyond consumption of bush-food.

Sediment fluxes and sinks based on total sediment load for Magela Creek in the Australian wet–dry tropics have been constructed from detailed measurements of turbidity, suspended sand and bedload for the 10-year period from 2001–2002 to 2010–2011. The present work showed that the sediment-trap efficiency of the vegetated wetlands on lower Magela is high at ~89.5%.

Constructed wetlands could play a crucial role in integrated agro-environmental management of intensive agricultural landscapes. An experimental wetland was created within the Venetian drainage system to reduce nutrient runoff and test the adaptability of seven macrophyte species in a floating treatment wetland system. A promising depurative effect emerges from the concentration trends throughout the system. Carex spp. adapted best to the floating wetlands.

Key stream fauna in Kakadu National Park face severe threats in 100+ years associated with climate change, invasive species, and mine-site rehabilitation. Sea level rise will salt the coastal floodplains and the fauna must then rely on reduced upstream refuges vulnerable to strong swings between more intense El Niños and La Niñas. Rates and extremes of future climate change appear unprecedented, making predictions associated with past climate change unreliable.

On the Kakadu floodplains, the distribution of different plant communities varies yearly, related to flooding duration and water depth. Because these floodplains are close to the coast, they are vulnerable to saltwater intrusion as the sea levels rise. The most obvious effect of this will be the transformation from freshwater vegetation to salt-tolerant plants in susceptible areas.

Sea-level rise associated with global warming will increase across Kakadu causing widespread saltwater intrusion. We aimed to understand how soil bacteria might respond to these impacts, by sampling transects in different river zones. We found diverse bacterial communities that were sensitive to soil variables, suggesting that saltwater intrusion may affect bacterial contributions to the dynamic floodplain ecosystems of Kakadu.

The coastal floodplains of the Kakadu Region of northern Australia are highly vulnerable to future sea level rise (SLR) and extreme weather events. A hydrodynamic model was developed to simulate the frequency and extent of saltwater inundation of future SLR scenarios from 2013 to 2100 (1.1 m above mean sea level), and was used to assess potential risk to freshwater floodplains.

The effects of ash from controlled fires on macroinvertebrate communities in UK headwater streams were investigated experimentally by depositing ash onto natural stream substrata in trays placed on streambeds. Ash deposition together with stream depth altered macroinvertebrate community composition. However, changes in species composition caused by ash deposition were smaller than differences among streams, suggesting that effects of ash may be small in these streams.