This study found that fish kills tended to occur when prolonged dry periods were followed by rapid and intensive rainfall after summer flood events. Summer floods can generate large volumes of hypoxic floodwater caused by rapid decomposition of floodplain organic matter. We suggest that estuarine fish migrate upstream during drier periods to follow the salt wedge and become trapped upstream during summer floods when hypoxic floodwaters discharge, resulting in fish kills.

Chrysosporum ovalisporum, a potentially toxic cyanobacterium unusual in temperate Australian fresh waters, occurred as a major bloom in the Murray River in 2016. Potential causes of the bloom were assessed, with water management within the headwater reservoir and higher water temperatures resulting from extremely hot summer weather being most likely. Similar blooms are likely in the future under forecast global warming.

Estuary perch are a long-lived estuarine-dependant fish. We found year class strength of the species was positively related to high flows over the spawning season and the austral winter, in addition to cooler annual temperatures in general. Climate change predictions of lower rainfall and higher temperatures in south-east Australia may result in prolonged periods of recruitment failure in the region.

This study evaluated the effects of heat stress on rainbow trout. Heat stress altered expression of heat shock protein family A (Hsp70) member 5 (HSPA5) mRNA, suggesting that HSPA5 plays a role in protecting tissues against damage caused by heat stress, with serious tissue damage occurring at temperatures above 24°C. The data can provide a reference for heat-resistant breeding programs and the aquaculture of cold-water fish.

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.

This study shows that illegal and non-selective glass eel (Anguilla anguilla) fishing in estuaries has considerable effects on both target and non-target species, hampering the functioning of the estuarine ecosystem, including its nursery function. The magnitude of the effect of these illegal practices was related to hydrological cycles, with higher catches in periods of higher river flow.

This study was undertaken to understand the abundance and seasonal recruitment patterns of freshwater eels in the western South Pacific, Fiji Islands. There are three species of freshwater eels in the region that recruit throughout the year with large intermittent recruitment periods. A robust understanding of freshwater eels is required to effectively use and conserve this resource.

This study investigated the feeding habits of the spirlin (Alburnoides bipunctatus) in a tributary of the River Vistula (Poland). The species consumed insects with an ontogenetic change in the proportion of the main taxonomic groups of prey in the diet. Small spirlin (juveniles) preferred chironomid larvae, whereas larger individuals (adults) showed a preference for Coleoptera, which can be attributed to the shift from benthic to open water feeding.

Tidal cycles and spatial and seasonal variations in salinity have a marked effect on the foraging and feeding patterns of fishes in tropical estuaries. Herein we demonstrate that a pufferfish species feeds the most during spring tides, and that its diet varies the most in more saline areas in the Amazon coastal zone.

This study investigated the downstream catadromous spawning migrations of congolli (Pseudaphritis urvillii), and subsequent juvenile recruitment, in the River Murray, Australia. During a period of freshwater scarcity, complete closure of tidal barrages obstructed migrations from freshwater habitats. In the subsequent spawning season, operation of a navigation lock facilitated passage past the barrages, and access to marine spawning habitats. In association, recruitment increased significantly. This illustrated the potential impact of tidal barriers on migrations and population dynamics of catadromous fish.

In this study, using total phosphorus data, we tested 12 phytoplankton-based diversity and biovolume metrics as indicators of water quality in a Neotropical lake over a 1-year study period. We also examined the effects of environmental variations and heterogeneous distributions of phytoplankton on metrics performance. Two metrics (the Phytoplankton Assemblage Index and the Cyanobacteria Bloom Index) were the most reliable; some variables, such as temperature and conductivity, may affect water quality estimation, and these two metrics are robust in the face of heterogeneous phytoplankton distribution.

This study describes the feeding patterns in a high-diversity Neotropical estuary and simulated the effect of resource loss on the fish community. Modelling results suggested that promoting diversity of resources, abiotic conditions and local feeding patterns increased food web robustness to human-mediated disturbances. The results also supported the notion that an improved understanding of food web structure can provide key insights to guide future research and policies.

Caves are peculiar and unknown systems, especially with regard to the invertebrate aquatic community. This study reveals that insect community patterns are driven by the physicochemical characteristics of the water, hydraulic features of the channel and substrate characteristics. The findings suggest that assemblages in each cave may reflect their local variability, and silting would likely have deleterious effects on aquatic insect communities.

Dive surveys of floating docks throughout southern California were used to quantify the spatial and temporal dynamics of fouling organisms. Non-native species were more abundant throughout the region and quickly dominated simulated novel artificial habitat, although community composition was more variable. These results are a first step in development of quantitative mitigation measures to offset impacts from this disturbance.

B. inops in the eastern Mediterranean Sea occurs preferentially, but not exclusively, inside submerged caves and exhibits photosynthetic activity. After transferring this sponge between the inside and outside of a submerged cave, we observed better performance with the inside-to-outside transfer than vice versa. These results suggest that: (1) submerged caves may supply sponges for artificial propagation (e.g. aquaculture); and (2) the sponge-associated photosynthetic micro-organisms may be active even under dim light conditions.

Summary. The first confirmed record of the moonfish, Mene maculata, and the crimson snapper, Lutjanus erythropterus, in Omani waters is reported. Fish specimens were collected using gill-net on the coast of Muscat City, Oman. The study reports on the largest recorded specimen of M. maculata. It also reports on the presence of a sustainable population of both species in the Oman Sea, Sultanate of Oman.