Search

Losses of river complexity and viable habitat has led to negative effects on Atlantic salmon. With the rapid population decline of Atlantic salmon, there has been an increase in river restoration and salmon reintroduction projects, and an understanding of substrate is a vital component in the restoration of these habitats. However, the isolation and/or inaccessibility of many of these rivers make the collection of this information challenging and expensive based on conventional survey approaches. This study looks at the feasibility and accuracy of conducting substrate analysis using low-cost uncrewed aerial vehicles (UAV) at seven transects through macroscale river habitat (riffles, runs and pools) on the Upper Salmon River located in Fundy National Park near Alma, New Brunswick, Canada. Using ArcGIS, a supervised classification was conducted separating the dry and submerged substrate for higher accuracy. An object-based image analysis was conducted in PCI for delineation of substrate size. Small ideal spawning substrate was found to be concentrated in slower flowing pools while large substrate was concentrated in faster flowing riffles. The substrate analysis was conducted with an accuracy of 79% for dry substrate and 86% for submerged substrate, demonstrating the potential of UAV use in salmon habitat analysis.

Marine spatial planning (MSP) is a management tool that could help mitigate the conflict that exists between the American lobster (Homarus americanus) fishery and the net-pen salmon aquaculture industry in the Canadian Maritime provinces. We developed adult American lobster species distribution models (SDMs) for use in MSP in Liverpool, Nova Scotia, through remote sensing data collection methods. A single-beam echo sounder was used to collect bathymetry and seafloor substrate data, and an aerial drone collected lobster presence data through the georeferenced photography of lobster trap buoys. The SDMs display trends in lobster presence likelihood that correspond with established patterns of habitat selection in adult lobsters. The areas where lobsters are predicted to have the highest likelihood of presence are sections of hard and rocky substrate, though that association is confounded by depth. The uncertainty of the SDMs was quantitatively assessed and the importance of explicitly analysing the effects of scale and resolution of spatial data are highlighted.

The objective of this study was to estimate the impact of infestation pressures on the abundance of the parasitic sea louse, Lepeophtheirus salmonis, in the Bay of Fundy, New Brunswick (NB), Canada, using the Fish-iTrends database for the years 2009-2018. Infestation pressures were calculated as time-lagged weighted averages of the abundance of adult female (AF) sea lice within a site (internal infestation pressure: IIP) and among sites (external infestation pressure: EIP). The EIP weights were calculated from seaway distances among sites and a Gaussian kernel density for bandwidths of 5 to 60 km. The EIP with a bandwidth of 10 km had the best fit, as determined with Akaike's information criterion, and historical AF sea lice abundance. This estimated dispersal distance of 10 km was similar to previous studies in Norway, Scotland and in New Brunswick. The infestation pressures estimated from empirical AF sea lice abundance within and among sites significantly increased the abundance of AF sea lice (p

The health and welfare of farmed fish are highly dependent on environmental conditions. Under suboptimal conditions, the negative impact on welfare can cause changes in fish behaviour. Acoustic tags can provide high resolution and high frequency data to monitor fish positioning within the cage, which can be used to infer swimming behaviour. In this study, implanted acoustic tags were used to monitor the three-dimensional positioning of Atlantic salmon (Salmo salar) at a commercial farm in Nova Scotia, Canada. The one-month study period allowed the characterisation of background behaviour and changes in behaviour in relation to different environmental conditions, namely, water characteristics in terms of dissolved oxygen and temperature caused by the fall overturn, storm conditions, and feeding activity. The three-dimensional position of 15 fish was recorded using high temporal resolution (3 s). Fish movement was characterised by calculating four fish variables: distance from the centre of the cage [m], depth [m], velocity [ms−1], and turning angle [°]. The population swam in a counterclockwise swimming direction around 4 ± 2 m depth at an average speed of 0.61 ± 0.38 ms−1. After the fall overturn, the population moved significantly towards cage centre while decreasing velocity, and non-significant differences in depth and turning angle were observed. During feeding periods, a significant increase in depth and velocity, as well as a reduction in turning angle were observed. The storm event did not cause any significant change in the four fish variables. While some of the behavioural changes were difficult to assess with respect to causation, the high resolution, high frequency data provide unique detailed positioning information to further our understanding of the swimming behaviour of farmed fish.

Wild lobster (Homarus americanus) abundance was monitored before, during, and after salmon (Salmo salar) aquaculture production in a bay on Grand Manan Island, New Brunswick, Canada, in an 8-year survey, 2008 to 2015. Diver transects and free-area spot-dives were used to measure the carapace length and determine sex (including berried state) of each lobster encountered both inside (farm) and outside (reference) the lease boundaries. In pairwise comparisons of each sampling date, there was no significant difference between the number of lobsters inside the salmon farming area versus a nearby reference site and no significant difference in the number of berried females inside or out of the farm lease area. Combining data from all lobster surveys (farm and reference sites) indicated an increase over 8 years, similar in slope to the increase of the trap fishery in Lobster Fishing Area (LFA) 38. These results indicate that the fish farm had no obvious impact on lobster density at any point in the salmon production cycle and that inshore lobster abundance followed trends similar to those of the general fishery of LFA 38.

Carrying Capacity (CC) has emerged as a potential tool to sustainably manage human activities such as aquaculture. However, interdisciplinary and integrated frameworks for holistic CC assessments are still missing. The goal of this study was to generate expert consensus on best evaluative practices for holistic CC assessments of ocean-based salmon aquaculture. To achieve this goal, a 3-round Delphi study was conducted with 21 aquaculture and carrying capacity experts from around the world. Experts emphasized that the holistic CC process should i) engage all stakeholders in the process, ii) consider the combination of social, political, ecological, and economic aspects, iii) respond to changes over time, iv) consider multiple spatial and temporal scales, and v) be understandable and clear to all stakeholders involved. Furthermore, the expert panel emphasized the need for a cyclical and dynamic process that allows for the incorporation of feedback in the planning stages, embracing adaptive management. Due to the early stages of truly holistic assessments, the experts recognized challenges related to knowledge uncertainties and lack of approaches to integrate socio-economic data with ecological and physical data, potential conflicts arising from a multi-stakeholder process, and ill-equipped governance structures. The proposed guidelines and framework could help address some of the conceptual and procedural barriers to implementing holistic assessments into decision-making and may position CC as a useful decision-support tool for governments seeking sustainable aquaculture management.

We sought to understand factors associated with refusal of adjuvant radiotherapy in endometrial cancer and its impact on outcomes.Data from the National Cancer Database for patients who underwent surgery for nonmetastatic endometrial cancer between 2004 and 2015 were pooled. The Pearson χ test and multivariate logistic regression analyses were used to assess demographic, clinical, and treatment factors. Inverse probability of treatment weighting was used to account for differences in baseline characteristics. Kaplan-Meier analyses and doubly-robust estimation with multivariate Cox proportional hazards modeling were used to analyze overall survival (OS).We identified 4739 of 80,803 patients (5.9%) who refused radiotherapy. Factors associated with refusal were: no insurance (relative risk [RR]=1.66, P0.01), Medicare (RR=1.42, P0.01), living50 miles from treatment (RR=1.34, P0.01), Charlson-Deyo Comorbidity Scores of 1 (RR=1.16, P0.01) or ≥2 RR=1.38, P0.01), age above 60 years (RR=1.28, P0.01), International Federation of Gynecology and Obstetrics (FIGO) stages IIIA (RR=1.63, P0.01) and IIIC (RR=1.65, P0.01) disease, papillary (RR=1.69, P0.01) and clear cell histology (RR=1.64, P0.01). Factors associated with radiation therapy receipt included: Hispanic race (RR=0.61, P0.01), income$63,000 (RR=0.89, P=0.044), undergoing chemotherapy (RR=0.17, P0.01), FIGO stages IB (RR=0.81, P0.01) and II (RR=0.70, P0.01) disease, and lymphadenectomy (RR=0.79, P0.01). After weighting, 5-year OS was significantly lower with refusal (74.3% vs. 79.7%, P0.01). This survival decrement was maintained across FIGO stages.We identified characteristics associated with radiation refusal, including socioeconomic barriers, advanced disease stage, and histology. Refusal of radiotherapy conferred decreased OS across FIGO stages.

Visually-based approaches using techniques such as sediment surface images as well as sediment profile imaging (SPI) have been applied previously in the assessment of benthic impacts of organic enrichment. New visually-based benthic health indices (VBH and Surface Index) that integrate various visual properties was developed for muddy and sandier sediments, respectively. Visual indices were compared to the existing sulfide-based thresholds often used in environmental monitoring programs (EMPs). We utilized both techniques as well as geochemical indicators of eutrophication to detect benthic impacts at shallow shellfish and finfish farms in Nova Scotia, Canada. The visual indices were able to capture a non-sulfidic anaerobic condition in the sediments missed by the current sulfide-based system. Our results indicate that as presently configured, the visual based index will provide a more stringent standard in the EMPs that currently rely on a sulfide-based classification system, and thus affect regulatory judgement.

The need to employ management strategies that recognize ecosystem services and their trade-offs is considered a cornerstone for the implementation of an Ecosystem Approach to Aquaculture (EAA), yet it is unclear how to operationalize these concepts. Here, the role of certification and sustainable seafood ranking programs (sustainability schemes) in maintaining ecosystem services and supporting an EAA was explored. The representation of ecosystem services within sustainability scheme criteria, as well as the attributes of those criteria, were assessed using marine salmon aquaculture as a case study. Criteria reflected a range of ecosystem services and support reducing pressure on those services. However, consideration of the resilience capacity of ecosystem services, recognition of enhancements to ecosystem services, and attributes that support cost-benefit analysis of salmon farming appear to be limited within sustainability scheme criteria. Overall, the farm-scale assessment approach of many sustainability schemes appears to be incongruent with the broader spatial perspective required to operationalize EAA.

In marine ecosystems, oceanographic processes often govern host contacts with infectious agents. Consequently, many approaches developed to quantify pathogen dispersal in terrestrial ecosystems have limited use in the marine context. Recent applications in marine disease modeling demonstrate that physical oceanographic models coupled with biological models of infectious agents can characterize dispersal networks of pathogens in marine ecosystems. Biophysical modeling has been used over the past two decades to model larval dispersion but has only recently been utilized in marine epidemiology. In this review, we describe how biophysical models function and how they can be used to measure connectivity of infectious agents between sites, test hypotheses regarding pathogen dispersal, and quantify patterns of pathogen spread, focusing on fish and shellfish pathogens.

BACKGROUND: We compared injury incidence and mechanisms among youth, high school (HS), and National Collegiate Athletic Association (NCAA) boys’ and men’s lacrosse athletes for the 2014–2015 to 2016–2017 lacrosse seasons. METHODS: Multiple injury surveillance systems were used to capture 21 youth boys’, 22 HS boys’, and 20 NCAA men’s lacrosse team-seasons of data during the 2014–2015 to 2016–2017 seasons. Athletic trainers reported game and practice injuries and athlete exposures (AEs). Injuries included those occurring during a game and/or practice and requiring evaluation from an athletic trainer and/or physician. Injury counts, rates per 1000 AEs, and injury rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated. RESULTS: The injury rate in youth was higher than those reported in HS (10.3 vs 5.3 per 1000 AEs; IRR = 2.0; 95% CI: 1.6–2.4) and the NCAA (10.3 vs 4.7 per 1000 AEs; IRR = 2.2; 95% CI: 1.9–2.5). When considering time loss injuries only (restricted participation of ≥24 hours), the injury rate in youth was lower than those reported in HS (2.0 vs 2.9 per 1000 AEs; IRR = 0.7; 95% CI: 0.5–0.95) and the NCAA (2.0 vs 3.3 per 1000 AEs; IRR = 0.6; 95% CI: 0.4–0.8). The concussion rate in youth was higher than those in HS (0.7 vs 0.3 per 1000 AEs; IRR = 2.4, 95% CI: 1.1–5.2) and the NCAA (0.7 vs 0.3 per 1000 AEs; IRR = 2.1, 95% CI: 1.2–3.7). Injuries at the youth, HS, and NCAA levels were most commonly associated with stick contact, inflammatory conditions (including bursitis, tendonitis, and other unspecified inflammation), and noncontact mechanisms, respectively. CONCLUSIONS: Although the time loss injury rate was lowest in youth boys’ lacrosse, the concussion rate was the highest. Injury prevention approaches should be specific to the mechanisms associated with each level of play (eg, equipment skill development in youth).

Bivalve aquaculture requires the alteration of natural populations of filter-feeders by artificially increasing their density. A bivalve farm could have negative consequences for the ecosystem if the filtration pressure of stocked biomass surpasses the capacity of the system to replenish the depleted resources. The concept of ecological carrying capacity, understood as the magnitude of aquaculture activity in a given area that can be supported without leading to unacceptable changes in the aquatic environment, is commonly used to inform management and regulatory decisions of bivalve aquaculture. In this study, a hydrodynamic model has been coupled to an ecological model that simulates the main dynamics of organic seston to evaluate the effects of bivalve aquaculture on seston supply and assess ecological carrying capacity. The spatially-explicit model allows the identification of areas where organic seston could be reduced beyond precautionary thresholds of ecosystem resilience. The model has been applied to three coastal embayments in Nova Scotia (Canada) that differ in water circulation and inlet/coastal complexity. The outcomes of the model suggest that the current aquaculture operations in Sober Island, Wine Harbour, and Whitehead are within the ecological carrying capacity of the ecosystem for bivalve aquaculture. The simulation of additional hypothetical stocking scenarios had demonstrated the relevance of local water circulation to the ecological carrying capacity of the system, and consequently for aquaculture operations. Accordingly, the placement of leases in areas with optimal circulation should be considered for planning purposes. The capability of the model to explore hypothetical scenarios could be used as a tool to guide management decisions in regard to site selection for new aquaculture sites.

Finfish aquaculture is a source of dissolved nutrients, which can impact water quality in the wider environment. Therefore, the potential effects of dissolved nutrient loading must be considered if management is to transition towards an Ecosystem Approach to Aquaculture. In this study, the dissolved nitrogen dispersion pattern from a rainbow trout farm in Port Mouton (Nova Scotia, Canada) was simulated and evaluated in the context of potential toxicity for a foundation seagrass species. A range of scenarios defined under a precautionary approach were simulated using a fully spatial hydrodynamic model. These worst-case scenarios predicted a maximum nitrogen concentration at any moment of the day of 7.5 μM, which is below the expected toxicity threshold for seagrass. Further scenarios demonstrated that the increased dispersion caused by the wind could drop these values by 45–50% in the vicinity of the farm, suggesting the relevant role of wind forcing in nitrogen dispersion. This outcome suggests that the decline of seagrass reported in some parts of Port Mouton bay are unlikely to have been triggered by dissolved nutrients discharged from the farm. This case-study demonstrates the value of ecosystem modelling to make science-based and transparent decisions to implement an ecosystem approach to aquaculture.

Open ocean fish farming involves containment of cultured animals under environmental conditions influenced by seasonal variation and water quality. Recently, an important area of research focus has been on water quality monitoring to improve aquaculture management. The development of novel sensors that report in real-time is critical to improve the monitoring capacity of farms, while increasing the understanding of the dynamics of environmental variables. In this study, commercially available, real-time dissolved oxygen and temperature sensors were distributed in the center of 19 cages at a commercial Atlantic salmon (Salmo salar) farm located within Shelburne Bay, Nova Scotia (Canada) and four reference sites. The site had an average depth of 15 m, while the cages consisted of nets 10 m deep. The dense deployment allowed for insight into the spatial and temporal variability of dissolved oxygen throughout the farm. Tide was determined to have the most significant impact on dissolved oxygen levels, with its influence varying depending on cage location within the farm. As waters flow from one end of the farm to the other, driven by tidal advection, fish behaviour and physiology, as well as flow restriction from cage infrastructure reduce oxygen levels in cages downstream. This results in oxygen concentrations out of phase on opposite ends of the farm, with higher oxygen levels at one end of the farm (i.e. 8.24 ± 0.29 mg L−1) and lower oxygen levels at the other (i.e. 5.38 ± 0.34 mg L−1) at any given phase of the tidal cycle. As Atlantic salmon become stressed and exhibit a reduced appetite at oxygen levels below 4–6 mg L−1, depending on temperature, it is important to accurately monitor the entirety of the farm. This study examined the patterns and drivers, specifically tide, of dissolved oxygen throughout a commercial salmon farm to understand the oxygen dynamics and make informed decisions that impact fish growth and welfare.

Context Recent injury-surveillance data for collegiate-level cross-country athletes are limited. Objective To describe the epidemiology of National Collegiate Athletic Association (NCAA) men's and women's cross-country injuries during the 2009–2010 through 2013–2014 academic years. Design Descriptive epidemiology study. Setting Aggregate injury and exposure data collected from 25 men's and 22 women's cross-country programs, providing 47 and 43 seasons of data, respectively. Patients or Other Participants Collegiate student-athletes participating in men's and women's cross-country during the 2009–2010 through 2013–2014 academic years. Main Outcome Measure(s) Injury rates; injury rate ratios (RRs); injury proportions by body site, diagnosis, and apparatus; and injury proportion ratios were reported with 95% confidence intervals (CIs). Results The Injury Surveillance Program captured 216 injuries from men's cross-country and 260 injuries from women's cross-country, leading to injury rates of 4.66/1000 athlete-exposures (AEs) for men (95% CI = 4.04, 5.28) and 5.85/1000 AEs for women (95% CI = 5.14, 6.56). The injury rate in women's cross-country was 1.25 times that of men's cross-country (95% CI = 1.05, 1.50). Most injuries affected the lower extremity (men = 90.3%, women = 81.9%). The hip/groin-injury rate in women (0.65/1000 AEs) was higher than that in men (0.15/1000 AEs; RR = 4.32; 95% CI = 1.89, 9.85). The ankle-injury rate in men (0.60/1000 AEs) was higher than that in women (0.29/1000 AEs; RR = 2.07; 95% CI = 1.07, 3.99). Common diagnoses were strains (men = 19.9%, women = 20.4%) and inflammation (men = 18.1%, women = 23.8%). The majority of injuries were classified as overuse (men = 57.6%, women = 53.3%). Conclusions Consistent with prior research, injury distributions varied between male and female athletes, and the injury rate among females was higher. Understanding the epidemiology of these cross-country injuries may be important for developing appropriate preventive interventions.

Coastal embayments are dynamic open systems characterized by multiple sedimentary environments with specific biogeochemical properties, which instead are influenced by physicochemical and biological processes (e.g., hydrodynamics, carbon deposition, abiotic-chemical reactions, macrofaunal and microbial activity). In this study, a novel approach that combines benthic habitat mapping, empirical measurements, and multivariate analysis was used 1) to determine the variability of benthic primary production, respiration, and denitrification in different sediment types; and 2) to examine how sediment nutrient fluxes are influenced by organic content, porosity, salinity, temperature, depth, light availability, habitat, and sediment type. Of the total observed variance in benthic metabolic activity, 12.6%–66.5% was accounted for by these variables. Results highlight the important role of benthic diversity and their contribution to energy and matter cycling in coastal sediments. Consideration of these factors is key for the prediction of benthic processes at scales relevant for coastal management and valuation of associated ecosystem services.

Accurate maps representing seagrass spatial distribution are essential components for effective monitoring and management of coastal vegetated habitats. Satellite and acoustic remote sensing provide valuable spatial data for seagrass mapping, though few studies have evaluated the complementarity of these methods. In this study, the complementarity of seagrass mapping was assessed through comparison of acoustic and satellite remote-sensing data sets. QuickBird® satellite imagery representing the seagrass landscape of the Richibucto estuary, New Brunswick, Canada, was classified through an object-based procedure and evaluated against a single-beam sonar data set. Acoustic percentage cover values were classified into binary presence/absence format through the application of a decision threshold, allowing comparison with satellite data using the error matrix and derived metrics. Though the binary satellite classification resulted in relatively high accuracy compared with independent ground reference data, agreement between satellite and acoustic data sets was limited. Local differences in seagrass prevalence and patchiness affected classification accuracy, highlighting the potential for under-or overestimating seagrass cover when applying bay-scale classification to areas with different landscape structure. These results emphasize the importance of landscape context in seagrass mapping. Satellite and acoustic remote sensing were seen to fundamentally differ in their depiction of the landscape. Comparison of multiple remote-sensing methods allowed for assessment of complementarity as well as ecologically relevant insight to seagrass spatial dynamics, with implications for mapping and monitoring of seagrass habitats.

Intertidal landscapes are highly complex and dynamic habitats that exhibit variability over a range of spatial and temporal scales. The spatial arrangement of structure-forming biogenic features such as seagrasses and bivalves influences ecosystem function and the provision of important ecosystem services, though quantification and monitoring of intertidal landscape structure has been hindered by challenges collecting spatial data in the coastal zone. In this study, an intertidal landscape mosaic of eelgrass ( Zostera marina) and blue mussels ( Mytilus edulis) was observed using low-altitude aerial photography from a balloon-mounted digital camera platform. Imagery representing seagrass-bivalve landscape structure was classified and analysed using multiple metrics of landscape composition and configuration at the patch scale and the landscape scale. Patch-scale imagery was compared to a previously collected dataset in order to track temporal changes in seagrass patch metrics over a 26-month period. Seagrass and bivalve patches exhibited distinct spatial patterning at different spatial scales. At the patch scale, the change in seagrass metrics was consistent with patch border expansion at the expense of patch density and integrity. These methods demonstrate a novel approach for collecting high-resolution spatial data that could also be valuable to physical geographers dealing with similar fine-scale landscapes. The application of spatial metrics at multiple spatial scales quantified elements of the configuration and composition of a seagrass-bivalve habitat mosaic and allowed for the tracking of patch metrics through time to depict landscape change. Continued development of landscape metrics within intertidal habitats will increase understanding of the ecological function of these areas with benefits to management and monitoring of ecosystem health.

Temperature affects nearly all biological rates and consequently is fundamental to individual development time and timing of phenological events. One example is the duration of the pelagic larval stage of mussels, which is crucial for determining the magnitude and timing of recruitment, as well as population dispersal patterns. Understanding the impact of temperature on the rate of larval development is key to predicting the timing of settlement and optimizing mussel seed collection. Advising mussel farmers on Prince Edward Island about the ideal timing for collector deployment is one of the goals of the Mussel Monitoring Program (MMP). In this study we examine the relationship between the phenology of larval development based on MMP data, and satellite measurements of sea surface temperature. The analyses indicated that the first day of the year on which 10 –20% of the pool of mussel larvae reached 250 mm could be predicted using the thermal integral measure growing degree-days. While this finding confirmed the importance of temperature for mussel larval phenology, the effect of other environmental variables such as phytoplankton quantity and quality cannot be dismissed.

A spatially explicit coupled hydrodynamic-biogeochemical model was developed to study a coastal ecosystem under the combined effects of mussel aquaculture, nutrient loading and climate change. The model was applied to St Peter's Bay (SPB), Prince Edward Island, Eastern Canada. Approximately 40 % of the SPB area is dedicated to mussel (Mytilus edulis) longline culture. Results indicate that the two main food sources for mussels, phytoplankton and organic detritus, are most depleted in the central part of the embayment. Results also suggest that the system is near its ultimate capacity, a state where the energy cycle is restricted to nitrogen-phytoplankton-detritus-mussels with few resources left to be transferred to higher trophic levels. Annually, mussel meat harvesting extracts nitrogen (N) resources equivalent to 42 % of river inputs or 46.5 % of the net phytoplankton primary production. Under such extractive pressure, the phytoplankton biomass is being curtailed to 1980's levels when aquaculture was not yet developed and N loading was half the present level. Current mussel stocks also decrease bay-scale sedimentation rates by 14 %. Finally, a climate change scenario (year 2050) predicted a 30 % increase in mussel production, largely driven by more efficient utilization of the phytoplankton spring bloom. However, the predicted elevated summer temperatures (> 25 A degrees C) may also have deleterious physiological effects on mussels and possibly increase summer mortality levels. In conclusion, cultivated bivalves may play an important role in remediating the negative impacts of land-derived nutrient loading. Climate change may lead to increases in production and ecological carrying capacity as long as the cultivated species can tolerate warmer summer conditions.

The success of shellfish aquaculture as well as its sustainability relies on adjusting the cultured biomass to local ecosystem characteristics. Oyster filter-feeding activity can control phytoplankton concentration, reaching severe depletion in extreme situations, which can threaten ecological sustainability. A better understanding of oyster–phytoplankton interaction can be achieved by constructing ecosystem models. In this study, a fully-spatial hydrodynamic biogeochemical model has been constructed for the Richibucto Estuary in order to explore oyster carrying capacity. The biogeochemical model was based on a classical nutrient–phytoplankton–zooplankton–detritus (NPZD) approach with the addition of a Dynamic Energy Budget (DEB) model of Crassostrea virginica. Natural variation of chlorophyll was used as a benchmark to define a sustainability threshold based on a resilience framework. Scenario building was applied to explore carrying capacity of the system. However, the complex geomorphology of the Richibucto Estuary and the associated heterogeneity in water residence time, which is integral in estuarine functioning, indicate that the carrying capacity assessment must be specific for each area of the system. The model outcomes suggest that water residence time plays a key role in carrying capacity estimations through its influence on ecological resistance.

The filtration activity of cultured mussels may exert a strong control on phytoplankton populations. Given that phytoplankton constitutes the base of marine food webs, carrying capacity in shellfish aquaculture sites has been commonly studied in terms of phytoplankton depletion. However, spatial and temporal variability of phytoplankton concentration in coastal areas present a methodological constraint for using phytoplankton depletion as an indicator in monitoring programs, and necessitates intensive field campaigns. The main goal of this study is to explore the potential of different bivalve performance indices for use as alternatives to phytoplankton depletion as cost-effective indicators of carrying capacity. For that, a fully spatial hydrodynamic–biogeochemical coupled model of Tracadie Bay, an intensive mussel culture embayment located in Prince of Edward Island (Canada), has been constructed and scenario building has been used to explore the relationship between phytoplankton depletion and bivalve performance. Our underlying premise is that overstocking of bivalves leads to increased competition for food resources, i.e. phytoplankton, which may ultimately have a significant effect on bivalve growth rate and performance. Following this working hypothesis, the relationships among bay-scale phytoplankton depletion and three bivalve physiological indices, one static, condition index, and two dynamic, tissue mass and shell length growth rates, have been simulated. These three metrics present methodological advantages compared to phytoplankton depletion for incorporation into monitoring programs. Although significant correlations among phytoplankton depletion and the three physiological indices have been observed, shell length growth rate is shown as the most sensitive indicator of carrying capacity, followed by tissue mass growth rate and then by condition index. These results demonstrate the potentiality of using bivalve physiological measurements in monitoring programs as indicators of ecosystem status.

Estuarine ecosystems are highly sensitive not only to projected effects of climate change such as ocean warming, acidification, and sea-level rise but also to the incidence of nor'easter storms and hurricanes. The effects of storms and hurricanes can be extreme, with immediate impact on coastal geomorphology and water circulation, which is integral to estuarine function and consequently to provision of ecosystem services. In this article, we present the results of a natural estuarine-scale experiment on the effects of changes in coastal geomorphology on hydrodynamics and aquaculture production. A bay in Prince Edward Island, Canada, was altered when a nor'easter storm eroded a second tidal inlet through a barrier island. Previous field and modeling studies allowed a comparison of prestorm and post-storm circulation, food limitation by cultured mussels, and aquaculture harvest. Dramatic increases in mussel production occurred in the year following the opening of the new inlet. Model studies showed that post-storm circulation reduced food limitation for cultured mussels, allowing greater growth. Climate change is expected to have severe effects on the delivery of marine ecosystem services to human populations by changing the underlying physical-biological coupling inherent to their functioning.

Eelgrass (Zostera marina) is an important feature of coastal ecosystems in Atlantic Canada, providing a suite of valuable ecosystem services. These services, and its sensitivity to stressors, have prompted efforts to characterize the spatial and temporal dynamics of eelgrass landscapes in order to facilitate management and monitoring of coastal ecosystem health. Current methods for broad-scale mapping of eelgrass rely on aerial remote sensing and may not be appropriate in certain types of landscapes, particularly in turbid waters and areas lacking distinct boundaries. This study takes a novel approach to the quantification and analysis of seagrass landscape structure at multiple spatial scales using acoustic data and local spatial statistics. Data from a single-beam acoustic survey in Richibucto, New Brunswick, Canada were analyzed with geostatistical techniques and the Getis-Ord Gi* local spatial statistic in order to detect statistically significant zones of high and low cover in an estuarine seagrass bed. Results showed distinct and significant patterns in seagrass cover at multiple spatial scales within a region of apparently continuous spatial cover. Boundaries between areas of high and low cover were also detected. This study demonstrates how acoustic data and local spatial statistics can be used to quantify landscape pattern and to further the application of landscape techniques in the marine environment.

Shellfish aquaculture implies the placement of artificial structures in the coastal environment and the alteration of natural bivalve populations, which calls for the establishment of legislative regulatory frameworks based on an ecosystem approach. One of the challenges for policy makers is the need to monitor the effectiveness of management actions. In this study, a meta-analysis across different bays, covering a large spatial scale in Atlantic Canada, was performed to test the response of two potential indicators of aquaculture intensity: (1) the bivalve growth using both Dynamic Energy Budget (DEB) and Scope For Growth (SFG) approaches, and (2) the bivalve condition index (CI = (meat weight/shell weight) × 100). Our underlying premise was that overstocking of bivalves leads to increased competition for food resources, which might ultimately have a significant effect on bivalve growth performance and the CI. Bivalve growth performance for cohorts of Mytilus edulis and Crassostrea virginica were simulated by combining satellite remote sensing (temperature and chlorophyll) with individual based models using both DEB and SFG approaches. These models were calibrated for each cohort, by adjusting the half-saturation coefficient of the food ingestion function term ( X K ), which is a common parameter related to feeding behavior in both approaches. A significant correlation between X K and lease coverage (lease area/bay area, dimensionless) was found for M. edulis . However, because of unrealistic X K values in some M. edulis cohorts and the lack of consistent simulations for C. virginica precluded using X K as a reliable indicator of aquaculture intensity. By contrast, according to the observed results CI emerged as a good indicator of aquaculture intensity for both species. A General Additive Model (GAM) for C. virginica provided a regression that included the initial dry meat weight as a linear term and the lease area as a non-linear term, explaining a total deviance of 59.9% in describing final CI values. The GAM for M. edulis included only non-linear terms, lease coverage, and lease area, explaining a total deviance of 61.0%. Since the CI theoretically integrates the effects of changing trophic conditions over time, the good relationship between the CI and lease/bay characteristics provides a scientific framework for its use as a reliable ecological indicator of aquaculture intensity. From an applied perspective, this finding is of relevance because the CI is easy to measure and is widely available in government and industry datasets.

Bivalve suspension-feeding can produce horizontal gradients of particulate suspended matter, or seston, which may impair bivalve growth among other impacts to the coastal ecosystem. We proposed a method to assess the concentration of seston at different locations along a shellfish farm by means of measurements of the depth-averaged diffuse attenuation coefficient of downwelling irradiance at 490 nm, K, from at least two autonomous buoys equipped with a vertical array of irradiance sensors. Two approaches were compared. First, horizontal gradients of chlorophyll plus phaeopigments (Chl) were calculated from K using an empirical algorithm derived from water samples. In the second approach, gradients of particulate suspended matter were calculated after correcting K for the attenuation due to water and riverine colored dissolved organic matter (CDOM), estimated from continuous in situ measurements of salinity. The method was assessed in a mussel farm in Ship Harbour (Nova Scotia, Canada). The proposed method is relatively insensitive to the angular distribution of downwelling irradiance, biofouling, frame-shading, and wave focusing; but it cannot be easily applied in places with strong and sustained sediment resuspension. This method can complement and validate current modeling studies of seston depletion, and it can assist managerial activities and legislative requirements of shellfish aquaculture. This method can also be used to assess gradients of other ecologically relevant substances (i.e., CDOM, phytoplankton, and seston) in applications associated with sewage discharges, river runoff, harmful algal blooms, suspension-feeding invasive bivalves, and other horizontally variable phenomena in the coastal ocean.

A calibrated fine resolution physical-biogeochemical model coupled with a dynamic energy budget (DEB) is used to investigate the local and system scale interactions between a mussel farm and the receiving coastal ecosystem. Using a set of published parameters for the DEB, the coupled model reproduces quite accurately both the local mussel growth and its spatial distribution over the farm area. Mussel related process rates are also well reproduced, allowing the study of mussel/environment interactions. Results show the local importance of cultured mussels in the cycling of nitrogen within the cultivation area. Despite the strongly reduced influence exerted by the mussel farm at the scale of the entire system, the culture activity still has the ability to alter the structure of Grande-Entree lagoon's ecosystem. The coupled model results show that the mussel stock could be greatly increased before reaching the maximum production capacity of Grande-Entree lagoon. However, when the ecological aspect is accounted for, using model results along with objective criteria such as the depletion footprint curve, the overall carrying capacity of Grande-Entree lagoon must be significantly reduced. The coupled fine scale numerical model developed for this study gives the opportunity to assess the ecological carrying capacity of a coastal region for shellfish culture accounting for both local and system scale processes.

GREAT DESIGN EMERGES when programmatic requirements are not only satisfied but become aspects of a compelling and enduring human experience. Grant-WTW architects have devised a process—Focus Week—that helps it understand and respond to the critical experiential dimensions involved in designing a building. In this case study, Linda Hartman, with Jon Grant's input, shares a snapshot of the Focus Week methodology as it was used in the design of a dining hall for Salisbury State University, in Maryland.

In DSM-IV-TR, trichotillomania (TTM) is classified as an impulse control disorder (not classified elsewhere), skin picking lacks its own diagnostic category (but might be diagnosed as an impulse control disorder not otherwise specified), and stereotypic movement disorder is classified as a disorder usually first diagnosed in infancy, childhood, or adolescence. ICD-10 classifies TTM as a habit and impulse disorder, and includes stereotyped movement disorders in a section on other behavioral and emotional disorders with onset usually occurring in childhood and adolescence. This article provides a focused review of nosological issues relevant to DSM-V, given recent empirical findings. This review presents a number of options and preliminary recommendations to be considered for DSM-V: (1) Although TTM fits optimally into a category of body-focused repetitive behavioral disorders, in a nosology comprised of relatively few major categories it fits best within a category of motoric obsessive–compulsive spectrum disorders, (2) available evidence does not support continuing to include (current) diagnostic criteria B and C for TTM in DSM-V, (3) the text for TTM should be updated to describe subtypes and forms of hair pulling, (4) there are persuasive reasons for referring to TTM as ‘‘hair pulling disorder (trichotillomania),’’ (5) diagnostic criteria for skin picking disorder should be included in DSM-V or in DSM-Vs Appendix of Criteria Sets Provided for Further Study, and (6) the diagnostic criteria for stereotypic movement disorder should be clarified and simplified, bringing them in line with those for hair pulling and skin picking disorder. Depression and Anxiety 27:611–626, 2010. r 2010 Wiley-Liss, Inc.

Downward fluxes of organic biodeposits under suspended mussel culture cause benthic impacts such as microbial mat production. Quantifying sediment erosion in these coastal ecosystems is important for understanding how fluxes of organic matter and particulates contribute to benthic–pelagic coupling. Critical shear velocity ( u ⁎), erosion rates and particle size distributions of resuspended sediment were measured at two sites; an impacted muddy site with extensive mussel culture (site 1), and a coarser sandier site with less mussel influence (site 2), using a new method for assessing sediment erosion at Tracadie Bay, Prince Edward Island in August 2003. Shear forces were generated by vertically oscillating a perforated disc at controlled frequencies. These forces correspond to shear velocity, using a re-designed and calibrated Particle Erosion Simulator. Undisturbed sediment cores obtained by divers and grab (sub-cored using a Plexiglas™ cores) were exposed to shear stress to compare differences between collection methods. Microbial mats were present at site 1 which initially biostabilized sediment against erosion due to ‘armoring’ of the sediment, but onset of erosion was abrupt once these mats failed. Erosion sequences at site 2 (without mat cover) were smoother resulting in less material being eroded. Mean mass of material eroded was 47 and 23 g m − 2 min − 1 at sites 1 and 2 respectively. Mat area cover and shear velocity was strongly related. Critical shear velocities varied between 1.70 and 1.77 cm s − 1 , with no obvious differences between location or collection method, so sediments from these two contrasting sites had identical mean critical shear velocities. Significant differences existed in the concentrations of chlorophyll a , colloidal and bulk carbohydrates, between mats and bare sediment from site 1. Particle sizes measured by videography of resuspended sediment at different shear velocities ranged from 100 μm (the minimum diameter capable of being detected by the system), to large mat fragments of 1700 μm for both sites. These results provide evidence of the relevance of using a portable erosion device to indicate how sediment erodability is affected by mussel–microbial relationships.

The Mackenzie River is the largest river on the North American side of the Arctic and its huge freshwater and sediment load impacts the Canadian Beaufort Shelf. Huge quantities of sediment and associated organic carbon are transported in the Mackenzie plume into the interior of the Arctic Ocean mainly during the freshet (May to September). Changing climate scenarios portend increased coastal erosion and resuspension that lead to altered river-shelf-slope particle budgets. We measured sedimentation rates, suspended particulate matter (SPM), particle size and settling rates during ice-free conditions in Kugmallit Bay (3–5 m depth). Additionally, measurements of erosion rate, critical shear stress, particle size distribution and resuspension threshold of bottom sediments were examined at four regionally contrasting sites (33–523 m depth) on the Canadian Beaufort Shelf using a new method for assessing sediment erosion. Wind induced resuspension was evidenced by a strong relationship between SPM and wind speed in Kugmallit Bay. Deployment of sediment traps showed decreasing sedimentation rates at sites along an inshore–offshore transect ranging from 5400 to 3700 g m− 2 day− 1. Particle settling rates and size distributions measured using a Perspex settling chamber showed strong relationships between equivalent spherical diameter (ESD) and particle settling rates (r2 = 0.91). Mean settling rates were 0.72 cm s− 1 with corresponding ESD values of 0.9 mm. Undisturbed sediment cores were exposed to shear stress in an attempt to compare differences in sediment stability across the shelf during September to October 2003. Shear was generated by vertically oscillating a perforated disc at controlled frequencies corresponding to calibrated shear velocity using a piston grid erosion device. Critical (Type I) erosion thresholds (u⁎) varied between 1.1 and 1.3 cm s− 1 with no obvious differences in location. Sediments at the deepest site Amundsen Gulf displayed the highest erosion rates (22–54 g m− 2 min− 1) with resuspended particle sizes ranging from 100 to 930 µm for all sites. There was no indication of biotic influence on sediment stability, although our cores did not display a fluff layer of unconsolidated sediment. Concurrent studies in the delta and shelf region suggest the importance of a nepheloid layer which transports suspended particles to the slope. Continuous cycles of resuspension, deposition, and horizontal advection may intensify with reduction of sea ice in this region. Our measurements coupled with studies of circulation and cross-shelf exchange allow parameterization and modeling of particle dynamics and carbon fluxes under various climate change scenarios.

A fully-coupled biological-physical-chemical model of a coastal ecosystem was constructed to examine the impact of suspended mussel culture on phytoplankton biomass in Tracadie Bay, Prince Edward Island, Canada. Due to the extent of mussel culture there, we hypothesised that shellfish filtration would control the concentration and distribution of phytoplankton and other suspended particles in the bay. Circulation was delineated with a tidally-driven 2D numerical model and used to drive an ecosystem model with a focus on pelagic components including phytoplankton production, nutrients, detritus, and mussels. The benthos were treated as a sink. Nutrients and seston were forced by tidal exchange and river input, with phytoplankton additionally forced by light. Boundary conditions of seston and nutrients were derived from field studies with an emphasis on the contrast between spring (high river nutrients, low temperature) and summer (low river inputs and high temperatures). Model output was used to map phytoplankton carbon over the bay for each season and in the presence of mussels and river nutrient input. Results indicate severe depletion effects of mussel culture on overall phytoplankton biomass, but no spatial pattern that can be attributed to grazing alone. Primary production generated by nutrient-rich river water created a mid-bay spike in phytoplankton that dominated the spatial pattern of chlorophyll-based carbon. Model results were validated with surveys from a towed sensor array (Acrobat) that confirmed the river influence and indicated bay-wide depletion of 29% between high and low water. Our model results indicate that the farm-scale depletion emphasised in previous studies cannot simply be extrapolated to seston limitation at the ecosystem level. (C) 2007 Elsevier B.V. All rights reserved.

Suspended mussel culture entails loading high densities of juvenile mussels into mesh socks, and hanging them from floating longlines, often resulting in intraspecific crowding, reduced growth, and mussel yield. Despite this potential bottleneck in culture, there are few data on behavioral mechanisms that regulate juvenile density and growth rate. A field experiment was conducted with culture socks to examine the effects of stocking density (High ∼800 mussels/30.5 cm; Low ∼400 mussels/30.5 cm), blue mussel species (Mytilus edulis and M. trossulus) and environment on early development of the culture population. In situ photography and direct sampling were used to generate time series of mussel size, valve gape, siphon area, shell orientation, and emergence in experimental socks at a commercial farm in Ship Harbour, Nova Scotia, Canada. Moored CTD-current meters and water sampling were used to characterize the sites. Emergence from the culture socks required 1–2 mo, with faster initial emergence in...

A field experiment was carried out to investigate the patterns of macrobenthic recolonization and to determine the effects of biodeposition on benthic communities at an intertidal oyster culture site in New Brunswick, Canada. Total organic deposition in azoic organic-free sediment trays was generally higher within the farm compared to reference sites. Two weeks after deployment of trays, total organic content had reached 1.1%. The abundance, species number, and diversity of the macrobenthic community were positively correlated with the total organic content in the experimental trays, but the correlations between community parameters and organic content were negative in the ambient sediment. The results suggest that organic matter in sediment may have positive effects on macrobenthic infauna at low levels as an additional food source but may be harmful to benthic animals at high levels. This study also indicates that location in the intertidal zone is a major parameter affecting the community structure of macrobenthic colonization.

Marine bivalves have been designated ecosystem engineers owing to their capacity to control estuarine water quality, particle dynamics, and primary production. Globally, bivalves have higher production than any other cultured animal. Large populations of natural, invasive, and cultured bivalves are suggested to cause changes in coastal ecosystem function through suspension-feeding of particles and biodeposition of waste materials. Association of bivalves with particle depletion is a trophic tenet of coastal ecosystems, but there are no previous observations of this process except at small scales. Using airborne hyperspectral remote sensing, we show direct evidence of aquaculture impacts at the ecosystem scale (kilometres), documenting significant depletion of phytoplankton through a blue mussel (Mytilus edulis) farm in eastern Canada, compared with dispersion in circulation model results without mussels. Understanding of factors controlling primary production and ecosystem processes in the coastal zone is critical in light of growing reliance on this region for development and resource extraction worldwide.