Canadian Water and Wastewater Association

This paper reports on a series of laboratory experiments designed to evaluate a mechanism for the voluntary provision of public good. The public good is provided if the total contributions meet or exceed a threshold and all contributions are returned if the public good is not provided. The members of the group all know the threshold, the incomes, and the valuations assigned the public good by all other members. The results support the prediction that this mechanism will yield Pareto efficient outcomes and suggest that economic agents adopt strategies which form equilibria satisfying certain refinements to the Nash equilibrium.

Changes in Lake Superior's fish community are reviewed from 1970 to 2000. Lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis) stocks have increased substantially and may be approaching ancestral states. Lake herring (Coregonus artedi) have also recovered, but under sporadic recruitment. Contaminant levels have declined and are in equilibrium with inputs, but toxaphene levels are higher than in all other Great Lakes. Sea lamprey (Petromyzon marinus) control, harvest limits, and stocking fostered recoveries of lake trout and allowed establishment of small nonnative salmonine populations. Natural reproduction supports most salmonine populations, therefore further stocking is not required. Nonnative salmonines will likely remain minor components of the fish community. Forage biomass has shifted from exotic rainbow smelt (Osmerus mordax) to native species, and high predation may prevent their recovery. Introductions of exotics have increased and threaten the recovering fish community. Agencies have little influence on the abundance of forage fish or the major predator, siscowet lake trout, and must now focus on habitat protection and enhancement in nearshore areas and prevent additional species introductions to further restoration. Persistence of Lake Superior's native deepwater species is in contrast to other Great Lakes where restoration will be difficult in the absence of these ecologically important fishes.

We review the status of the Lake Huron fish community between 1970 and 1999 and explore the effects of key stressors. Offshore waters changed little in terms of nutrient enrichment, while phosphorus levels declined in inner Saginaw Bay. Introduced mussels (Dreissena spp.) proliferated and may have caused a decline in Diporeia spp. This introduction could have caused a decline in lake whitefish (Coregonus clupeaformis) growth and condition, with serious repercussions for commercial fisheries. Bythotrephes, an exotic predatory cladoceran, and other new exotics may be influencing the fish community. Sea lampreys (Petromyzon marinus) remained prevalent, but intensive control efforts on the St. Mary's River may reduce their predation on salmonines. Overfishing was less of a problem than in the past, although fishing continued to reduce the amount of lake trout (Salvelinus namaycush) spawning biomass resulting from hatchery-reared fish planted to rehabilitate this species. Massive stocking programs have increased the abundance of top predators, but lake trout were rehabilitated in only one area. Successful lake trout rehabilitation may require lower densities of introduced pelagic prey fish than were seen in the 1990s, along with continued stocking of hatchery-reared lake trout and control of sea lamprey. Such reductions in prey fish could limit Pacific salmon (Oncorhynchus spp.) fisheries.

Four different types of equilibrium are possible within a two‐player model of society where only armed self‐enforcement of property rights is possible. The main underlying parameters are the total resource endowment and the initial distribution of this endowment between the players. The parameter space is partitioned into regions in which the respective types of equilibrium occur The equilibrium types involve positive arms expenditure by, respectively, neither player the richer player, and both players; the latter case involves a sub‐type in which the poorer player's entire endowment is expended on arms. (JEL D30, D72, D74)

Nosema ceranae is a microsporidian fungus that parasitizes the midgut epithelial cells of honey bees, Apis mellifera. Due to the role that midgut microorganisms play in bee health and immunity, food supplementation with prebiotics and probiotics may assist in the control of N. ceranae. The dietary fiber prebiotics acacia gum, inulin, and fructooligosaccharides, as well as the commercial probiotics Vetafarm Probotic, Protexin Concentrate single-strain (Enterococcus faecium), and Protexin Concentrate multi-strain (Lactobacillus acidophilus, L. plantarum, L. rhamnosus, L. delbrueckii, Bifidobacterium bifidum, Streptococcus salivarius, and E. faecium) were tested for their effect on N. ceranae spore loads and honey bee survivorship. Bees kept in cages were inoculated with N. ceranae spores and single-dose treatments were administered in sugar syrup. Acacia gum caused the greatest reduction in N. ceranae spore numbers (67%) but also significantly increased bee mortality (62.2%). However, Protexin Concentrate single-strain gave similarly reduced spore numbers (59%) without affecting the mortality. In a second experiment, multiple doses of the probiotics revealed significantly reduced spore numbers with 2.50 mg/mL Vetafarm Probotic, and 0.25, 1.25, and 2.50 mg/mL Protexin Concentrate single-strain. Mortality was also significantly reduced with 1.25 mg/mL Protexin Concentrate single-strain. N. ceranae-inoculated bees fed 3.75 mg/mL Vetafarm Probotic had higher survival than N. ceranae-inoculated bees, which was similar to that of non-inoculated bees, while N. ceranae-inoculated bees fed 2.50 mg/mL Protexin Concentrate single-strain, had significantly higher survival than both N. ceranae-inoculated and non-inoculated bees. Protexin Concentrate single-strain is promising as it can reduce N. ceranae proliferation and increase bee survivorship of infected bees, even compared to healthy, non-infected bees.

Preterm and term transitional milks of human subjects and mature milks of human subjects, non-human primates and non-primates were analysed for free amino acids (AA) using precolumn phenylisothiocyanate derivatization and liquid chromatography. Differences in free AA between three types of human milk were small. Milks of pinnipeds (seals and sea lions) contained the highest levels of total free AA (8634-20,862 mumol/l), while the milks of cows and sheep had the lowest levels of total free AA (1061-1357 mumol/l). The milks of human subjects, chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla), elephants (Elephas maximus), horses and pigs had intermediate levels of total free AA (3069-7381 mumol/l). Glutamic acid was the most abundant free AA in milks of human subjects (1339-2157 mumol/l), non-human primates (423-2528 mumol/l), elephants (1332 mumol/l), horses (1119 mumol/l), and cows (349 mumol/l). Taurine was the most abundant free AA in milks of pinnipeds (5776-13,643 mumol/l), pigs (1238 mumol/l), goats (1150 mumol/l) and sheep (341 mumol/l). Taurine was the second most abundant free AA in milks of human subjects and non-human primates, while histidine was the second most abundant free AA in milks of pinnipeds. Milks of each species had a distinctive free AA pattern which may reflect the relative importance of the free AA during early postnatal development.

Abstract We developed indices of lake trout Salvelinus namaycush status in the main basin of Lake Huron (1973–2010) to understand increases in the relative abundance of wild year-classes during 1995–2010. Sea lamprey Petromyzon marinus wounds per 100 lake trout declined from 23.63 in 2000 to 5.86–10.64 in 2002–2010. The average age-7 lake trout catch per effort per recruitment (CPE/R; fish·305 m of gill net−1·million stocked yearlings−1) increased from 0.56 for the 1973–1990 year-classes to 0.92 for the 1991–2001 year-classes. Total CPE (fish/305 m of gill net) declined from 16.4 fish in 1996 to 4.1 fish in 2010, but the percentage of age-5 and younger lake trout steadily decreased from more than 70% before 1996 to less than 10% by 2009. The modal age in gill-net catches increased from age 5 before 1996 to age 7 by 2005. The average adult CPE increased from 2.8 fish/305 m of gill net during 1978–1995 to 5.34 fish/305 m of gill net during 1996–2010. The 1995–2010 year-classes of wild fish were more abundant than previous year-classes and were associated with the relatively high adult abundance during 1996–2010. Until the 2002 year-class, there was no decline in age-7 CPE/R; until 2008, there was no decline in adult CPE. Low survival of the 2002 and 2003 year-classes of stocked fish was related to the event of alewife Alosa pseudoharengus population collapse in 2003–2004. Lake trout in the main basin of Lake Huron are undergoing a transition from a hatchery stock to a wild stock, accompanied by an increased uncertainty in delayed recruitment. Future management should pay more attention to the protection of wild recruitment and the abundance of the spawning stock. Received April 20, 2011; accepted December 30, 2011

Nosema ceranae is an emerging pathogen of the western honey bee (Apis mellifera L.), and thus its seasonality and impact on bee colonies is not sufficiently documented for North America. This study was conducted to determine the infection intensity, prevalence, and viability of N. ceranae in >200 honey bee colonies during spring, summer, and fall, in a North American region. We also determined the relationship of N. ceranae infections with colony populations, food stores, bee survivorship, and overwinter colony mortality. The highest rates of N. ceranae infection, prevalence, and spore viability were found in the spring and summer, while the lowest were recorded in the fall. N. ceranae spore viability was significantly correlated with its prevalence and infection intensity in bees. Threshold to high levels of N. ceranae infections (>1,000,000 spores/bee) were significantly associated with reduced bee populations and food stores in colonies. Furthermore, worker bee survivorship was significantly reduced by N. ceranae infections, although no association between N. ceranae and winter colony mortality was found. It is concluded that N. ceranae infections are highest in spring and summer and may be detrimental to honey bee populations and colony productivity. Our results support the notion that treatment is justified when infections of N. ceranae exceed 1,000,000 spores/bee.

Fish maturation schedules vary greatly among systems and over time, reflecting both plastic and adaptive responses to ecosystem structure, physical habitats, and mortality (natural and fishing). We examined maturation schedules of commercially exploited lake whitefish ( Coregonus clupeaformis ) in the Laurentian Great Lakes (Lakes Michigan, Huron, and Superior) by estimating ages and lengths at 50% maturity, age-specific maturity ogives (age-specific probability of being mature), and probabilistic maturation reaction norms (PMRNs; a metric that accounts for effects of growth and mortality). Collectively, these estimates indicated variation in maturation schedules between sexes (i.e., males tend to mature at younger ages and shorter lengths than females) and among systems (midpoint estimates of PMRNs were smallest for Lake Michigan fish, intermediate for fish in the main basin of Lake Huron, and largest for fish in Lake Huron’s Georgian Bay and Lake Superior). Temporally, recent increases in age at 50% maturity in Lakes Huron and Michigan may primarily reflect plastic responses to decreased growth rates associated with ecosystem changes (e.g., declines of the native amphipod, Diporeia spp.). As plastic and adaptive changes in maturation schedules of fish stocks may occur simultaneously and require different management considerations, we recommend the concomitant analysis of multiple maturation indices.

BACKGROUND: Plankton are foundational to marine food webs and an important feature for characterizing ocean health. Recent developments in quantitative imaging devices provide in-flow high-throughput sampling from bulk volumes-opening new ecological challenges exploring microbial eukaryotic variation and diversity, alongside technical hurdles to automate classification from large datasets. However, a limited number of deployable imaging instruments have been coupled with the most prominent classification algorithms-effectively limiting the extraction of curated observations from field deployments. Holography offers relatively simple coherent microscopy designs with non-intrusive 3-D image information, and rapid frame rates that support data-driven plankton imaging tasks. Classification benchmarks across different domains have been set with transfer learning approaches, focused on repurposing pre-trained, state-of-the-art deep learning models as classifiers to learn new image features without protracted model training times. Combining the data production of holography, digital image processing, and computer vision could improve in-situ monitoring of plankton communities and contribute to sampling the diversity of microbial eukaryotes. RESULTS: Here we use a light and portable digital in-line holographic microscope (The HoloSea) with maximum optical resolution of 1.5 μm, intensity-based object detection through a volume, and four different pre-trained convolutional neural networks to classify > 3800 micro-mesoplankton (> 20 μm) images across 19 classes. The maximum classifier performance was quickly achieved for each convolutional neural network during training and reached F1-scores > 89%. Taking classification further, we show that off-the-shelf classifiers perform strongly across every decision threshold for ranking a majority of the plankton classes. CONCLUSION: These results show compelling baselines for classifying holographic plankton images, both rare and plentiful, including several dinoflagellate and diatom groups. These results also support a broader potential for deployable holographic microscopes to sample diverse microbial eukaryotic communities, and its use for high-throughput plankton monitoring.

Alternatives to the antibiotic fumagillin for the control of Nosema ceranae, a gut parasite of the honey bee, are needed. The prebiotics eugenol, chitosan, and naringenin and the probiotic Protexin® (Enterococcus faecium) provided in sugar syrup or protein patty either in spring or fall were evaluated for their effects on N. ceranae infection, colony population, honey yield and winter survivorship using field colonies. In the first year, spring treatments with eugenol, naringenin, and Protexin® significantly reduced N. ceranae infection and increased honey production, while Protexin® also increased adult bee populations and chitosan was ineffective. Fall treatments increased survivorship and decreased N. ceranae infection the following spring. In the second year, selected compounds were further tested with a larger number of colonies per treatment and only protein patty used in the spring and sugar syrup in the fall. Protexin® and naringenin significantly decreased N. ceranae infections and increased the population of adult bees after spring treatment, but did not affect honey yields. There were no differences between treatments for colony winter mortality, but surviving colonies that had been treated with Protexin® and naringenin were significantly more populated and had lower N. ceranae spore counts than control, non-treated colonies. Protexin® and naringenin were the most promising candidates for controlling N. ceranae and promoting honey bee populations, warranting further investigation. Future research should investigate the optimal colony dose and treatment frequency to maximize colony health.

HYPOTHESIS: The cochlear A-value measurement exhibits significant inter- and intraobserver variability, and its accuracy is dependent on the visualization method in clinical computed tomography (CT) images of the cochlea. BACKGROUND: An accurate estimate of the cochlear duct length (CDL) can be used to determine electrode choice, and frequency map the cochlea based on the Greenwood equation. Studies have described estimating the CDL using a single A-value measurement, however the observer variability has not been assessed. METHODS: Clinical and micro-CT images of 20 cadaveric cochleae were acquired. Four specialists measured A-values on clinical CT images using both standard views and multiplanar reconstructed (MPR) views. Measurements were repeated to assess for intraobserver variability. Observer variabilities were evaluated using intra-class correlation and absolute differences. Accuracy was evaluated by comparison to the gold standard micro-CT images of the same specimens. RESULTS: Interobserver variability was good (average absolute difference: 0.77 ± 0.42 mm) using standard views and fair (average absolute difference: 0.90 ± 0.31 mm) using MPR views. Intraobserver variability had an average absolute difference of 0.31 ± 0.09 mm for the standard views and 0.38 ± 0.17 mm for the MPR views. MPR view measurements were more accurate than standard views, with average relative errors of 9.5 and 14.5%, respectively. CONCLUSION: There was significant observer variability in A-value measurements using both the standard and MPR views. Creating the MPR views increased variability between experts, however MPR views yielded more accurate results. Automated A-value measurement algorithms may help to reduce variability and increase accuracy in the future.

BACKGROUND: Documenting an indication when prescribing antimicrobials is considered best practice; however, a better understanding of the evidence is needed to support broader implementation of this practice. OBJECTIVES: We performed a scoping review to evaluate antimicrobial indication documentation as it pertains to its implementation, prevalence, accuracy and impact on clinical and utilisation outcomes in all patient populations. ELIGIBILITY CRITERIA: Published and unpublished literature evaluating the documentation of an indication for antimicrobial prescribing. SOURCES OF EVIDENCE: A search was conducted in MEDLINE, Embase, CINAHL and International Pharmaceutical Abstracts in addition to a review of the grey literature. CHARTING AND ANALYSIS: Screening and extraction was performed by two independent reviewers. Studies were categorised inductively and results were presented descriptively. RESULTS: We identified 123 peer-reviewed articles and grey literature documents for inclusion. Most studies took place in a hospital setting (109, 89%). The median prevalence of antimicrobial indication documentation was 75% (range 4%-100%). Studies evaluating the impact of indication documentation on prescribing and patient outcomes most commonly examined appropriateness and identified a benefit to prescribing or patient outcomes in 17 of 19 studies. Qualitative studies evaluating healthcare worker perspectives (n=10) noted the common barriers and facilitators to this practice. CONCLUSION: There is growing interest in the importance of documenting an indication when prescribing antimicrobials. While antimicrobial indication documentation is not uniformly implemented, several studies have shown that multipronged approaches can be used to improve this practice. Emerging evidence demonstrates that antimicrobial indication documentation is associated with improved prescribing and patient outcomes both in community and hospital settings. But setting-specific and larger trials are needed to provide a more robust evidence base for this practice.

Indigenous Peoples’ lives, cultures, and values are defined largely by their long-term relationships with the lands, waters, and lifeforms of their territories. Their stories, names, ceremonies, and connections with the plants and animals on which they have depended over countless generations are cornerstones of their knowledge systems, systems of governance and decision-making, traditions of intergenerational knowledge transmission, and values and responsibilities associated with natural and human domains alike. For First Nations of North America’s Northwest Coast, as for many other Indigenous Peoples, the arrival of European newcomers disrupted both the natural world and associated cultural practices in interconnected ways. The industrial exploitation of lands and resources had wide-ranging effects: traditional land and resource appropriation; impacts on culturally significant habitats by industrial-scale fishing, logging, and mining; and discrimination and marginalization contributing to resource alienation. This paper documents some experiences of Kwakwaka’wakw and other Coastal First Nations in coping with the cultural effects of environmental loss. It highlights their concern for the ecological integrity of lands and waters formerly under their stewardship but reshaped by non-Native extractive economies, and describes how these losses have affected the cultural, social, and physical health of Kwakwaka’wakw peoples up to the present time.

Migration can be a behavioural response to poor or declining home range habitat quality and can occur when the costs of migration are overcome by the benefi ts of encountering higher- quality resources elsewhere. Despite dramatic ecosystem-level changes in the benthic food web of the Laurentian Great Lakes since the colonization of dreissenid mussels, coincident changes in condition and growth rates among benthivorous lake whitefi sh populations have been variable. We hypothesized that this variation could be in part mitigated by differences in migratory habits among populations, where increased migration distance can result in an increased probability of encountering high-quality habitat (relative to the home range). Results from four Great Lakes populations support this hypothesis; relative growth rates increased regularly with migration distance. The population with the largest average migration distance also had the least reduction in size-at-age during a period of signifi cant ecosystem change and among the highest estimated consumption and activity rates. In comparison, the population with the greatest declines in size-at-age was among the least mobile, demonstrating only moderate rates of consumption and activity. The least mobile population of lake whitefi sh was supported by a remnant Diporeia population and has experienced only moderate temporal growth declines. Our study provides evidence for the potential role of migration in mitigating the effects of ecosystem change on lake whitefi sh populations.

Les conceptions de Kohlberg sur le développement moral ont suscité de nombreux travaux empiriques et théoriques qui aboutissent en définitive à une conception renouvelée de l’évolution morale au cours de la période de l’adolescence. La première partie de cet article présente les éléments principaux de cette conception, avec la prise en compte des variabilités intra-et inter individuelles et de quelques-unes des reformulations proposées après Kohlberg. Cette synthèse aboutit à deux séries d’interrogations. Tout d’abord, la perspective de Kohlberg étant essentiellement « socio-cognitive », il apparaît nécessaire de chercher à préciser quatre interprétations possibles du caractère « socio-cognitif » habituellement attribué au développement moral. Ensuite, la variabilité constatée du développement moral invite à poser la question des déterminants possibles de cette évolution et de sa différenciation. Sur ce dernier aspect, cinq directions d’analyse explicatives sont envisagées.

After two years of bidirectional selection for low and high rates of Varroa destructor population growth (LVG and HVG, respectively) in honey bee (Apis mellifera) colonies in Ontario, Canada, significant differences between the two genotypes were observed. LVG colonies had V. destructor population increases over the summer of 1.7 fold compared to 9.6 fold for HVG colonies by Generation 2. Additionally, HVG colonies had significantly higher mite infestation rates in adult bees compared to LVG colonies for both selected generations. DWV prevalence and levels were significantly higher in HVG colonies than in LVG colonies in Generation 1 but not in Generation 2. Winter mortality rates of Generation 1 colonies were significantly different at 26% and 14% for the HVG and LVG genotypes, respectively. The results of this study thus far indicate that selection for LVG may result in colonies with lower V. destructor infestation rates, lower prevalence, and levels of DWV and higher colony winter survivorship. Future work will focus on determining what mechanisms are responsible for the genotypic differences, estimating genetic parameters, and molecular analyses of the genotypes to identify candidate genes associated with resistance to V. destructor and DWV that could potentially be used for marker-assisted selection.

Abstract The parasitic mite Varroa destructor (Mesostigmata: Varroidae) is the main culprit of honey bee (Hymenoptera: Apidae) colony mortality in Ontario, Canada. Most beekeepers use synthetic acaricides to control V. destructor infestations in their colonies, but the use of these products increases the risk of V. destructor developing resistance to the active ingredients, which is a growing concern. This study sought to determine the efficacy of three synthetic acaricides approved for use in Canada for control of V. destructor infestations, amitraz (Apivar™), tau-fluvalinate (Apistan®), and flumethrin (Bayvarol®), using the Pettis test. The mite mortality rate in populations of V. destructor differed for the acaricides tested. Amitraz caused a significantly higher mite mortality rate (92%) than flumethrin (78%) and tau-fluvalinate (72%) did. Amitraz was classified as “mostly effective” (90–97%), whereas flumethrin and tau-fluvalinate were classified as “minimally effective” (< 80%) for V. destructor control in the mite populations studied. Variation in mite mortality due to acaricide exposure was observed between apiaries and regions. The results highlight the importance of periodically assessing the varroacidal activity of acaricides to inform decisions to control the parasite when implementing integrated pest management strategies.

Abstract The small hive beetle (SHB), Aethina tumida Murray (Coleoptera: Nitidulidae), is a non-native pest of honey bees ( Apis mellifera Linnaeus (Hymenoptera: Apidae)) newly introduced to Canada. The effectiveness of three in-hive traps was tested in springtime in West-Montérégie (southern Québec, Canada) and in late summer in Essex County (southern Ontario, Canada): AJ’s Beetle Eater™ (AJ’s Beetle Eater), Beetle Barn™ (Rossmann Apiaries), and Hood™ trap (Brushy Mountain Bee Farm). Traps were placed in the brood chamber of 12 colonies in West-Montérégie, and in 48 colonies in the top honey super in Essex County. In-hive traps were effective in reducing SHB populations without compromising the bee population or colony weight gain. In West-Montérégie, the Beetle Barn™ was the most effective trap during the first week, when SHB populations were high. It was less effective when honey bees sealed trap openings with propolis. In Essex County, the AJ’s Beetle Eater™ was the most effective throughout the trial. There was no difference in efficacy between the various solutions used in the Hood™ trap (mineral oil versus mineral oil and apple cider vinegar).

Honey bee viruses are serious pathogens that can cause poor colony health and productivity. We analyzed a multi-year longitudinal dataset of abundances of nine honey bee viruses (deformed wing virus A, deformed wing virus B, black queen cell virus, sacbrood virus, Lake Sinai virus, Kashmir bee virus, acute bee paralysis virus, chronic bee paralysis virus, and Israeli acute paralysis virus) in colonies located across Canada to describe broad trends in virus intensity and occurrence among regions and years. We also tested climatic variables (temperature, wind speed, and precipitation) as predictors in an effort to understand possible drivers underlying seasonal patterns in viral prevalence. Temperature was a significant positive predictor of the total number of viruses per sample, which was highest in British Columbia (mean = 5.0). Lake Sinai virus (LSV) was the most prevalent overall (at 89%) and had the highest infection intensity, at an average of 3.9 × 10 8 copies per bee. Acute bee paralysis virus was the least prevalent virus (at 4.7%) and had the lowest infection intensity (1.9 × 10 5 copies per bee). Surprisingly, including Varroa abundance as a covariate did not significantly improve model fit for any virus. All viruses, except Kashmir bee virus, varied by region, and one or more climatic variables were significant predictors for six of the nine viruses. Although climatic effects were often inconsistent among individual viruses, we show that climatic variables can be better predictors of virus intensity and occurrence than Varroa mite abundance, at least when infestation rates are low.