Morphological predictors of swimming speed performance in river and reservoir populations of Australian smelt Retropinna semoni.

Dam construction is a major driver of ecological change in freshwater ecosystems. Fish populations have been shown to diverge in response to different flow velocity habitats, yet adaptations of fish populations to river and reservoir habitats created by dams remains poorly understood. We aimed to evaluate divergence of morphological traits and prolonged swimming speed performance between lotic and lentic populations of Australian smelt Retropinna semoni and quantify the relationship between prolonged swimming speed performance and morphology. Prolonged swimming speed performance was assessed for 15 individuals from each of three river and two reservoir populations of R. semoni using the critical swimming speed test (Ucrit ). Body shape was characterized using geometric morphometrics, which was combined with fin aspect ratios and standard length to assess morphological divergence among the five populations. Best subsets model-selection was used to identify the morphological traits that best explain Ucrit variation among individuals. Our results indicate R. semoni from river populations had significantly higher prolonged swimming speed performance (Ucrit = 46.61 ± 0.98 cm s-1 ) than reservoir conspecifics (Ucrit = 35.57 ± 0.83 cm s-1 ; F1,74 = 58.624, Z = 35.938, P < 0.001). Similarly, R. semoni sampled from river populations had significantly higher fin aspect ratios (ARcaudal = 1.71 ± 0.04 and 1.29 ± 0.02 respectively; F(1,74) = 56.247, Z = 40.107, P < 0.001; ARpectoral = 1.85 ± 0.03 and 1.33 ± 0.02 respectively; F(1,74) = 7.156, Z = 4.055, P < 0.01). Best-subset analyses revealed Ucrit was most strongly correlated with pectoral and caudal fin aspect ratios (R2 adj = 0.973, AICc = 41.54). Body shape, however, was subject to a three-way interaction among population, habitat and sex effects (F3,74 = 1.038. Z = 1.982; P < 0.05). Thus sexual dimorphism formed a significant component of unique and complex variation in body shape among populations from different habitat types. This study revealed profound effects of human-altered flow environments on locomotor morphology and its functional link to changes in swimming performance of a common freshwater fish. While past studies have indicated body shape may be an important axis for divergence between lotic and lentic populations of several freshwater fishes, fin aspect ratios were the most important predictor of swimming speed in our study. Differences in body morphology here were inconsistent between river and reservoir populations, suggesting this aspect of phenotype may be more strongly influenced by other factors such as predation and sexual dimorphism.

Abiotic drivers of activity in a large, free-ranging, freshwater teleost, Murray cod (Maccullochella peelii).

The allocation of time and energy to different behaviours can impact survival and fitness, and ultimately influence population dynamics. Intrinsically, the rate at which animals expend energy is a key component in understanding how they interact with surrounding environments. Activity, derived through locomotion and basic metabolism, represents the principal energy cost for most animals, although it is rarely quantified in the field. We examined some abiotic drivers of variability in locomotor activity of a free-ranging freshwater predatory fish, Murray cod (Maccullochella peelii), for six months using tri-axial accelerometers. Murray cod (n = 20) occupied discrete river reaches and generally exhibited small-scale movements (<5 km). Activity was highest during crepuscular and nocturnal periods when water temperatures were warmest (19-30°C; January-March). As water temperatures cooled (9-21°C; April-June) Murray cod were active throughout the full diel cycle and dormant periods were rarely observed. Light level, water temperature and river discharge all had a significant, non-linear effect on activity. Activity peaked during low light levels, at water temperatures of ~20°C, and at discharge rates of ~400 ML d-1. The temporal changes observed in the behaviour of Murray cod likely reflect the complex interactions between physiological requirements and prey resource behaviour and availability in driving activity, and highlight the importance of empirical field data to inform bioenergetics models.

Adaptive Management of Environmental Flows.

Adaptive management enables managers to work with complexity and uncertainty, and to respond to changing biophysical and social conditions. Amid considerable uncertainty over the benefits of environmental flows, governments are embracing adaptive management as a means to inform decision making. This Special Issue of Environmental Management presents examples of adaptive management of environmental flows and addresses claims that there are few examples of its successful implementation. It arose from a session at the 11th International Symposium on Ecohydraulics held in Australia, and is consequently dominated by papers from Australia. We classified the papers according to the involvement of researchers, managers and the local community in adaptive management. Five papers report on approaches developed by researchers, and one paper on a community-led program; these case studies currently have little impact on decision making. Six papers provide examples involving water managers and researchers, and two papers provide examples involving water managers and the local community. There are no papers where researchers, managers and local communities all contribute equally to adaptive management. Successful adaptive management of environmental flows occurs more often than is perceived. The final paper explores why successes are rarely reported, suggesting a lack of emphasis on reflection on management practices. One major challenge is to increase the documentation of successful adaptive management, so that benefits of learning extend beyond the project where it takes place. Finally, moving towards greater involvement of all stakeholders is critical if we are to realize the benefits of adaptive management for improving outcomes from environmental flows.

Adaptive Management of Environmental Flows: Using Irrigation Infrastructure to Deliver Environmental Benefits During a Large Hypoxic Blackwater Event in the Southern Murray-Darling Basin, Australia.

Widespread flooding in south-eastern Australia in 2010 resulted in a hypoxic (low dissolved oxygen, DO) blackwater (high dissolved carbon) event affecting 1800 kilometres of the Murray-Darling Basin. There was concern that prolonged low DO would result in death of aquatic biota. Australian federal and state governments and local stakeholders collaborated to create refuge areas by releasing water with higher DO from irrigation canals via regulating structures (known as 'irrigation canal escapes') into rivers in the Edward-Wakool system. To determine if these environmental flows resulted in good environmental outcomes in rivers affected by hypoxic blackwater, we evaluated (1) water chemistry data collected before, during and after the intervention, from river reaches upstream and downstream of the three irrigation canal escapes used to deliver the environmental flows, (2) fish assemblage surveys undertaken before and after the blackwater event, and (3) reports of fish kills from fisheries officers and local citizens. The environmental flows had positive outcomes; mean DO increased by 1-2 mg L-1 for at least 40 km downstream of two escapes, and there were fewer days when DO was below the sub-lethal threshold of 4 mg L-1 and the lethal threshold of 2 mg L-1 at which fish are known to become stressed or die, respectively. There were no fish deaths in reaches receiving environmental flows, whereas fish deaths were reported elsewhere throughout the system. This study demonstrates that adaptive management of environmental flows can occur through collaboration and the timely provision of monitoring results and local knowledge.

Revealing Adaptive Management of Environmental Flows.

Managers of land, water, and biodiversity are working with increasingly complex social ecological systems with high uncertainty. Adaptive management (learning from doing) is an ideal approach for working with this complexity. The competing social and environmental demands for water have prompted interest in freshwater adaptive management, but its success and uptake appear to be slow. Some of the perceived "failure" of adaptive management may reflect the way success is conceived and measured; learning, rarely used as an indicator of success, is narrowly defined when it is. In this paper, we document the process of adaptive flow management in the Edward-Wakool system in the southern Murray-Darling Basin, Australia. Data are from interviews with environmental water managers, document review, and the authors' structured reflection on their experiences of adaptive management and environmental flows. Substantial learning occurred in relation to the management of environmental flows in the Edward-Wakool system, with evidence found in planning documents, water-use reports, technical reports, stakeholder committee minutes, and refereed papers, while other evidence was anecdotal. Based on this case, we suggest it may be difficult for external observers to perceive the success of large adaptive management projects because evidence of learning is dispersed across multiple documents, and learning is not necessarily considered a measure of success. We suggest that documentation and sharing of new insights, and of the processes of learning, should be resourced to facilitate social learning within the water management sector, and to help demonstrate the successes of adaptive management.

When trends intersect: The challenge of protecting freshwater ecosystems under multiple land use and hydrological intensification scenarios.

Intensification of the use of natural resources is a world-wide trend driven by the increasing demand for water, food, fibre, minerals and energy. These demands are the result of a rising world population, increasing wealth and greater global focus on economic growth. Land use intensification, together with climate change, is also driving intensification of the global hydrological cycle. Both processes will have major socio-economic and ecological implications for global water availability. In this paper we focus on the implications of land use intensification for the conservation and management of freshwater ecosystems using Australia as an example. We consider this in the light of intensification of the hydrologic cycle due to climate change, and associated hydrological scenarios that include the occurrence of more intense hydrological events (extreme storms, larger floods and longer droughts). We highlight the importance of managing water quality, the value of providing environmental flows within a watershed framework and the critical role that innovative science and adaptive management must play in developing proactive and robust responses to intensification. We also suggest research priorities to support improved systemic governance, including adaptation planning and management to maximise freshwater biodiversity outcomes while supporting the socio-economic objectives driving land use intensification. Further research priorities include: i) determining the relative contributions of surface water and groundwater in supporting freshwater ecosystems; ii) identifying and protecting freshwater biodiversity hotspots and refugia; iii) improving our capacity to model hydro-ecological relationships and predict ecological outcomes from land use intensification and climate change; iv) developing an understanding of long term ecosystem behaviour; and v) exploring systemic approaches to enhancing governance systems, including planning and management systems affecting freshwater outcomes. A major policy challenge will be the integration of land and water management, which increasingly are being considered within different policy frameworks.

Hypoxia, blackwater and fish kills: experimental lethal oxygen thresholds in juvenile predatory lowland river fishes.

Hypoxia represents a growing threat to biodiversity in freshwater ecosystems. Here, aquatic surface respiration (ASR) and oxygen thresholds required for survival in freshwater and simulated blackwater are evaluated for four lowland river fishes native to the Murray-Darling Basin (MDB), Australia. Juvenile stages of predatory species including golden perch Macquaria ambigua, silver perch Bidyanus bidyanus, Murray cod Maccullochella peelii, and eel-tailed catfish Tandanus tandanus were exposed to experimental conditions of nitrogen-induced hypoxia in freshwater and hypoxic blackwater simulations using dried river red gum Eucalyptus camaldulensis leaf litter. Australia's largest freshwater fish, M. peelii, was the most sensitive to hypoxia but given that we evaluated tolerances of juveniles (0.99 ± 0.04 g; mean mass ±SE), the low tolerance of this species could not be attributed to its large maximum attainable body mass (>100,000 g). Concentrations of dissolved oxygen causing 50% mortality (LC50) in freshwater ranged from 0.25 ± 0.06 mg l(-1) in T. tandanus to 1.58 ± 0.01 mg l(-1) in M. peelii over 48 h at 25-26 °C. Logistic models predicted that first mortalities may start at oxygen concentrations ranging from 2.4 mg l(-1) to 3.1 mg l(-1) in T. tandanus and M. peelii respectively within blackwater simulations. Aquatic surface respiration preceded mortality and this behaviour is documented here for the first time in juveniles of all four species. Despite the natural occurrence of hypoxia and blackwater events in lowland rivers of the MDB, juvenile stages of these large-bodied predators are vulnerable to mortality induced by low oxygen concentration and water chemistry changes associated with the decomposition of organic material. Given the extent of natural flow regime alteration and climate change predictions of rising temperatures and more severe drought and flooding, acute episodes of hypoxia may represent an underappreciated risk to riverine fish communities.

Gorlin's syndrome: An interesting case study and literature review.

Gorlin's syndrome, or basal cell nevus syndrome, is a relatively rare disease. It consists of a classic pentad of features comprised of multiple basal cell carcinomas, jaw cysts, calcification of the falx cerebri, pitting of the palmar and plantar surfaces and rib anomalies. A review of the clinical features, differential diagnosis, clinical work-up and current treatment is presented.

Le syndrome de Gorlin, ou naevomatose baso-cellulaire, est une maladie relativement rare. Il comprend cinq manifestations classiques, soit la présence de multiples carcinomes baso-cellulaires, de kystes maxillaires, de dépôts calcaires dans la faux du cerveau, de porokératose palmo-plantaire et d'anomalies costales. Nous passerons en revue, dans le présent article, les manifestations cliniques, le diagnostic différentiel, l'exploration clinique et le traitement actuel du syndrome.

Carpal tunnel syndrome and workers' compensation: A cross-Canada comparison.

Carpal tunnel syndrome (CTS) is the source of substantial workers' compensation claims in industrialized countries. Its pathogenesis, however, continues to be questioned. The purpose of the present study was to assess the attitudes of Canadian plastic surgeons toward Workers' Compensation Board (WCB)-supported claims for CTS and to assess patterns of resource allocation across Canada. Sixty-seven plastic surgeons were asked to read a clinical scenario and respond whether they would support a WCB claim for CTS. Provincial WCB offices were contacted and asked to provide statistics surrounding CTS claims for 1997 to 2001. Fifty-eight per cent (39 of 67) of surgeons surveyed felt that CTS should be covered as a WCB claim, while 42% (28 of 67) felt that it should not be covered by WCB. In British Columbia, 50% (six of 12) of surgeons were in support of the claim compared to 92% (11 of 12) of those from Alberta, 55% (17 of 31) of those from the Central Provinces and 42% (five of 12) of those from the Maritime Provinces. Trends of resource allocation and number of CTS claims per year are presented for the individual provinces for 1997 to 2001. An extensive literature review revealed that there is minimal to no evidence to support the view that CTS should be a compensated claim. As defined by the WCB of Canada, a compensated claim is one that "arises out of, and in the course of, employment and that results from causes and conditions peculiar to the trade, occupation or industry." The ambiguity in the beliefs of Canadian plastic surgeons in supporting CTS as a WCB claim reflects a situation where many of the decisions to cover CTS as a WCB claim are not evidence based.

Le syndrome du canal carpien (SCC) est la source d'importantes réclamations d'indemnisations de la part des travailleurs des pays industrialisés. Sa pathogenèse continue toutefois d'être remise en question. La présente étude vise à évaluer les attitudes des plasticiens canadiens par rapport aux réclamations reliées au SCC auprès de la Commission de la santé et de la sécurité du travail (CSST) ainsi que les schèmes d'attribution des ressources au Canada.Soixante-sept plasticiens ont été invités à lire un scénario clinique et à répondre s'ils soutiendraient une réclamation reliée au SCC auprès de la CSST. On a communiqué avec les bureaux de la CSST des provinces pour qu'ils fournissent des statistiques au sujet des réclamations reliées au SCC entre 1997 et 2001. Cinquante-huit pour cent (39 des 67) chirurgiens sondés pensaient que le SCC devrait être couvert par la CSST, tandis que 42 % (28 des 67) d'entre eux pensaient qu'il ne devrait pas l'être. En Colombie-Britannique, 50 % (six des 12) des plasticiens soutenaient la réclamation, par rapport à 92 % (11 des 12) des plasticiens de l'Alberta, à 55 % (17 des 31) de ceux des provinces centrales et à 42 % (cinq des 12) de ceux des Maritimes. Les tendances d'attribution des ressources et le nombre de réclamations reliées au SCC par année sont présentés pour chacune des provinces entre 1997 et 2001.Une analyse bibliographique fouillée révèle qu'il existe peu de données probantes, sinon aucune, pour soutenir une réclamation reliée au SCC. Telle qu'elle est définie par la CSST du Canada, une indemnisation découle de l'emploi et résulte de causes et de troubles propres au métier, à l'emploi ou à l'industrie. L'ambiguïté des convictions des plasticiens canadiens quant au soutien d'une réclamation reliée au SCC auprès de la CSST reflète le fait que bon nombre des décisions pour que la CSST indemnise les cas de SCC ne sont pas fondées sur des faits probants.