Visual census, photographic records and the trial of a video network provide first evidence of the elusive Sicyopterus cynocephalus in Australia

Opportunistic encounters with an elusive large-bodied sicydiine goby in a single plunge pool led us to photograph and deploy three video cameras to detect individuals in that pool. Subsequently, a catchment-wide search indicated that the species, eventually identified as Sicyopterus cynocephalus, was confined to the single pool where it was originally detected. A network of ten video cameras was then deployed to estimate the number of individuals of that species and of a congener, S. lagocephalus, by non-destructive means. This study provides the first record of S. cynocephalus in Australia, and showcases the synergy of active snorkel searches and a remote camera network in counting individuals of two sympatric species of Sicyopterus

Inter-decadal variation in diadromous and potamodromous fish assemblages in a near pristine tropical dryland river

Freshwater ecosystems are both incredibly biodiverse and highly threatened globally. Variation in environmental parameters including habitat and flow can substantially affect many ecological processes within riverine aquatic communities, but the ties between such parameters and ecology are neither well studied nor understood. In highly variable tropical dryland river systems, assessing such relationships requires data collection over inter-decadal time scales, which is not typically permitted on development schedules driven over short periods (including election and funding cycles). Here, we used seine net sampling data collected over an 18-year period in the tropical dryland Fitzroy River, Western Australia, to assess how environmental and temporal factors including habitat, seasonality, and inter-annual variation in wet season magnitude affect the community assemblage structure, recruitment, and growth of aquatic species in dryland rivers. Results demonstrated that macrohabitat (main channel vs floodplain creek) and the magnitude of wet season rains and resultant flooding both had a substantial influence on biotic communities, alongside seasonal and diel variation. The magnitude of wet season flooding (measured as river discharge volume) had the greatest impact on assemblage composition within floodplain creek habitats and was a significant driver of recruitment rates and growth of recruits and adults of several species examined. This study highlights key considerations for conserving dryland river systems and constituent biota. Specifically, these are maintaining (a) rhythmicity of flow within each year, (b) diversity of flow volume between years, and (c) a variety of habitat types including ephemeral, semi-permanent, and permanent shallow floodplain and deeper main channel pools, in order to support a diverse array of generalist and specialist diadromous and potamodromous fishes

Validating variation in radio-signal strength as an index of aquatic fauna activity

Abstract. Studying biological rhythms of activity and determining the external factors that influence behaviour of animals can be challenging in many aquatic habitats. We investigated the validity of using variations in radio-signal strength to quantify changes in activity of radio-tagged aquatic fauna on a small spatial scale under controlled conditions in the field. We monitored short-term activity (<1 min) of two aquatic species, rainbow trout (Oncorhynchus mykiss) and Murray River crayfish (Euastacus armatus), that differ markedly in their primary mode of movement. Simultaneous video monitoring confirmed that active and inactive periods for both species could be accurately determined by radio-telemetry, as were specific behaviours exhibited by trout. We were also able to quantify activity based on different radio-tag (coil and trailing whip antennas) and receiving antenna configurations (yagi and gap-loop antennas); however, we recommend use of control tags to provide reference data. Variation in radio-signal strength represents a valid means of monitoring activity of moderately site-attached aquatic species

Amphidromy Links a Newly Documented Fish Community of Continental Australian Streams, to Oceanic Islands of the West Pacific

BACKGROUND: Indo-Pacific high island streams experience extreme hydrological variation, and are characterised by freshwater fish species with an amphidromous life history. Amphidromy is a likely adaptation for colonisation of island streams following stochastic events that lead to local extirpation. In the Wet Tropics of north-eastern Australia, steep coastal mountain streams share similar physical characteristics to island systems. These streams are poorly surveyed, but may provide suitable habitat for amphidromous species. However, due to their ephemeral nature, common non-diadromous freshwater species of continental Australia are unlikely to persist. Consequently, we hypothesise that coastal Wet Tropics streams are faunally more similar, to distant Pacific island communities, than to nearby faunas of large continental rivers. METHODS/PRINCIPAL FINDINGS: Surveys of coastal Wet Tropics streams recorded 26 species, 10 of which are first records for Australia, with three species undescribed. This fish community is unique in an Australian context in that it contains mostly amphidromous species, including sicydiine gobies of the genera Sicyopterus, Sicyopus, Smilosicyopus and Stiphodon. Species presence/absence data of coastal Wet Tropics streams were compared to both Wet Tropics river networks and Pacific island faunas. ANOSIM indicated the fish fauna of north-eastern Australian coastal streams were more similar to distant Pacific islands (R = 0.76), than to nearby continental rivers (R = 0.98). MAIN CONCLUSIONS/SIGNIFICANCE: Coastal Wet Tropics streams are faunally more similar to distant Pacific islands (79% of species shared), than to nearby continental fauna due to two factors. First, coastal Wet Tropics streams lack many non-diadromous freshwater fish which are common in nearby large rivers. Second, many amphidromous species found in coastal Wet Tropics streams and Indo-Pacific islands remain absent from large rivers of the Wet Tropics. The evolutionary and conservation significance of this newly discovered Australian fauna requires clarification in the context of the wider amphidromous fish community of the Pacific

Recruitment of a critically endangered sawfish into a riverine nursery depends on natural flow regimes

The freshwater sawfish (Pristis pristis) was recently listed as the most Evolutionarily Distinct and Globally Endangered (EDGE) animal. The Fitzroy River in the remote Kimberley region of north-western Australia represents a significant stronghold for the species, which uses the freshwater reaches of the river as a nursery. There is also mounting pressure to develop the water resources of the region for agriculture that may substantially affect life history dynamics of sawfish in this system. However, the relationship between hydrology and population dynamics of freshwater sawfish was unknown. We used standardized catch data collected over 17 years to determine how wet season volume influences recruitment of freshwater sawfish into their riverine nursery. Negligible recruitment occurred in years with few days of high flood levels (above 98th percentile of cease-to-flow stage height), and relatively high recruitment occurred in years with 14 or more days of high flood levels. This relationship is indicative of a distinct boom-or-bust cycle, whereby freshwater sawfish rely almost entirely on the few years with large wet season floods, and the brief periods of highest water levels within these years, to replenish juvenile populations in the Fitzroy River nursery. This has direct implications for sustainable water resource management for the Fitzroy River basin in order to preserve one of the last known intact nursery habitats for this globally threatened species

Pebbled places preferred by people and pipefish in a World Heritage protected area

Although the ecological impacts of recreational activities in clear tropical streams are occasionally acknowledged and addressed, frequently they remain unmanaged, despite the fact that such streams are highly sought-after destinations for leisure pursuits. Here, we provide a case study on the ecological characteristics of the Indo-Pacific freshwater pipefish Microphis leiaspis Bleeker, 1854, which is a habitat specialist with little available information aside from its reproductive biology and the downstream migration patterns of its larvae. Drawing from our collective experiences, we describe the distribution and habitat of Microphis leiaspis and examine the potential impacts of various small-scale human activities on its livelihood, including those occur- ring within protected areas. In particular, we document incidental observations of human disturbances to adult Microphis leiaspis habitat in clear freshwater streams located within the Australian Wet Tropics (AWT) World Heritage Area. Using these observations as a foundation, we conceptualize human interactions with this species in the AWT streams and more broadly across the tropical Indo-Pacific Ocean. Microphis leiaspis occurs in the lower-mid course of short-steep-coastal-streams, in association with pebble fields, where it feeds on microscop- ic benthic invertebrates. We observed three distinct human behaviours in the pipefish habitat within the AWT, including stone-stacking, the construction of boulder-cobble dams, and stone-skimming. Additionally, we report on other small-scale human activities that may potentially impact this pipefish species in streams across Pacific Island nations and select coastal regions of continents. Our recommendation is to promote a ‘leave no trace’ approach to the public, which can be effectively communicated by key individuals such as indigenous custodi- ans, national park managers, locals, and tourism operators. This approach aims to minimize rock movement by people, thereby aiding in the protection of diadromous pipefish and other aquatic species residing in short-steepcoastal-streams

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Yellowfin bream, Acanthopagrus australis, reorientate individual shells in search of prey

Yellowfin bream, Acanthopagrus australis (Family Sparidae), were observed, photographed, and filmed grasping and manoeuvring benthic objects, primarily bivalve shells, and also gastropod shells, pebbles, leaves, sticks and macroalgae while searching for prey, based on four consecutive snorkelling sessions in an eastern Australian estuary. Observations were made during daily high-tide periods when yellowfin bream are known to forage most intensively, and only a few of the bream present at the site exhibited the novel behaviour. The discriminate object-shifting behaviour of this important fisheries species represents a nuance in yellowfin bream feeding ecology and highlights an additional microhabitat role that oyster reef carbonate production plays beyond the immediate reef

Growth, maximum daily ration and intraspecific cohabitation of the moray Gymnothorax polyuranodon (Muraenidae)in a freshwater aquarium

Some predominantly marine fish families include a small proportion of species that are obligate freshwater inhabitants, and there is accumulating evidence for obligate freshwater species within the family Muraenidae. Whether the muraenid Gymnothorax polyuranodon (Bleeker, 1854) can survive, grow and coexist over an extended period in captive freshwater conditions was tested following repeated observations of this species in freshwater streams of the Australian Wet Tropics. Changes in the body size of four individuals held in a 1200 litre freshwater aquarium revealed that yearly growth ranged from a minimum of 21.0cm total length (TL) and 2.4 times body mass to 26.5 cm TL and 3.9 times body mass. Maximum daily ration of individuals (fed worms, prawns and fish) ranged from 3.4% to 3.9% of body mass. Individuals coexisted peacefully, with only brief bouts of intraspecific aggression that included biting. While the full life cycle of G. polyuranodon remains unresolved, the current study reinforces field observations and microchemistry insights indicating that this species can occupy and grow in freshwater ecosystems, and points toward the likelihood that the species probably plays an important and previously unrecognised mesopredatory role

Cool Runnings: Antennae facilitate collective motion by a grounded group of adult antlions

[Extract] From 8 to 12 April 2020, daily observations were made of a group of adult antlions (also referred to as lacewings in Australia, Insecta: Neuroptera: Myrmeleontidae: Myrmeleontini) in an upward alignment clinging to the vertical stalk of a dead shrub (approximately 1.7–1.8 m above ground level). From the photographs, it is likely the species was Baliga australis (Banks, 1939) or a congeneric species. Initially, four individuals were aligned in single file near their nearest neighbor (or neighbors). When approached, the formation stayed in vertical alignment and rotated around the stalk to remain out of view of the circling photographer (Video S1). At times, the antlions remained still, and it was possible to photograph and film them laterally (Figure 1) and dorsally (Figure 2). Usually, during the day, the group occupied the shaded side of the stalk, before reacting to the observer. Upon closer inspection, it was clear that the antennae of each of the three lower individuals were positioned to enclose the posterior apices of the folded wings and tip of the abdomen of the individual positioned above them in sequence. Upon closer inspection, it was clear that the antennae of each of the three lower individuals were positioned to straddle the posterior folded wings of the individual positioned above them in sequence (Figure 1)