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  • OPEN ACCESS
    The many pathways of climate change affecting coastal ecosystems: a case study of western Vancouver Island, Canada
    FACETS • Vol. 10 • pp. 1 - 18
    Climate change threatens marine ecosystems with known effects on marine life, including changes in metabolic rates, survival, and community structure. Based on a structured literature review, we developed a conceptual “pathways of effects” model that summarizes how three stressors associated with climate change (warming, acidification, and storms) affect functional species groups on the West Coast of Vancouver Island, Canada. We identified 155 distinct pathways from the three stressors through 12 categories of biological effects ranging from changes in the biochemistry of individual organisms to effects on community composition. Most species groups were affected by several climate stressors and via many pathways, although individual studies generally considered only a small fraction of relevant pathways. These effects depended on the species of interest and geographical location, highlighting the importance of local research. Climate change stressors exert complex, sometimes contradictory effects that vary across ecological scales. For example, some stressors that adversely affected a species in laboratory studies appeared beneficial in community-scale field studies. Pathways of effects models are helpful tools to summarize scientific studies across ecological scales. Compiling them in standardized databases would allow researchers and practitioners to search across species and regions to better support ecosystem-based management and environmental impact assessment.
  • OPEN ACCESS
    The decline of walleye populations: an ecological tipping point?
    FACETS • Vol. 10 • pp. 1 - 17
    Walleye/ogaa (Sander vitreus (Mitchill)) (hereafter, walleye; ogaa = Ojibwe translation) populations have historically supported important multi-use, harvest-oriented fisheries. Despite intensive management, walleye populations have declined in the midwestern United States raising concerns about the sustainability of the species. Numerous factors have been implicated in walleye population declines, including climate change, habitat loss, invasive species, species-interactions, production overharvest (i.e., harvest consistently exceeding annual production), and changing angler behaviors. These factors have negatively influenced natural recruitment and contributed to depensatory recruitment dynamics. I provide a review and perspective suggesting that the current trajectory of walleye populations is at or nearing an ecological tipping point. Although fish populations are often considered compensatory (i.e., negatively density-dependent), current walleye populations appear prone to depensation (i.e., positive density dependence). My review and perspective suggest that a compensatory management perspective for walleye is misaligned. A change in management towards a depensatory resource focus using ecosystem-based fisheries management and the recognition of walleye fisheries as social–ecological systems is needed for conservation. If compensatory management ensues, walleye persistence will likely be further threatened because many drivers of change are outside of managerial control, and those commonly used within managerial control have seemingly been ineffective for sustaining or rehabilitating naturally reproducing walleye populations.
  • OPEN ACCESS
    Protection of seabed sediments in Canada's marine conservation network for potential climate change mitigation co-benefit
    FACETS • Vol. 10 • pp. 1 - 14
    Marine conserved areas (MCAs) can provide a range of ecological and socio-economic benefits, including climate change mitigation from the protection and enhancement of natural carbon storage. Canada's MCA network is expanding to encompass 30% of its Exclusive Economic Zone by 2030. At present, the network aims to integrate climate change mitigation by protecting coastal vegetated blue carbon ecosystems (saltmarsh, seagrass, kelp). Here, we argue that incorporating unvegetated seabed sediments could bring similar benefits. Seabed sediments can store and/or accumulate high densities of organic carbon, and due to their large spatial extent, contain carbon stores orders of magnitude larger than coastal vegetated habitats. We estimate that currently designated MCAs encompass only 10.8% of Canada's seabed sediment organic carbon stocks on the continental margin, and only 13.4% of areas with high carbon densities. Proposed MCAs would cover an additional 8.8% and 6.1% of total stocks and high carbon areas, respectively. We identify an additional set of high-priority seabed areas for future research and potential protection, ranking their importance based on carbon stocks, proxies for lability, and ecological/biological significance. The incorporation of seabed sediments into MCA networks could support climate change mitigation by preventing future releases of stored carbon.
  • OPEN ACCESS
    Evaluation of a decade of management of a North American aquatic invasive species (Nitellopsis obtusa) highlights scale-dependent effectiveness and monitoring gaps
    FACETS • Vol. 10 • pp. 1 - 14
    Nitellopsis obtusa (starry stonewort) is an invasive macroalga subject to substantial control efforts in the Midwestern United States; however, there has not been systematic evaluation of treatment effectiveness. We synthesized management approaches and outcomes using monitoring performed over a decade-long period across 38 lakes in Indiana, Wisconsin, and Minnesota. Copper-based algaecide treatments were the primary means of control, followed by physical removal methods or combination treatments. Control efforts and associated monitoring data varied by spatial scale, as did surveyors’ N. obtusa sampling methods. At the largest (whole-lake) scale, we found no evidence that algaecide treatments were slowing expansion or reducing abundance of N. obtusa within infested lakes. At smaller, within-lake scales, we found that algaecide and physical treatments could reduce N. obtusa frequency and biomass, but outcomes were highly variable. At the smallest scales, hand pulling was an effective containment strategy for small, localized populations that were detected early. These results highlight the need to set realistic goals for N. obtusa control and develop improved management techniques. There were also critical gaps in monitoring that limited our ability to evaluate treatment effectiveness. In particular, increased monitoring of unmanaged reference lakes and untreated areas within managed lakes is needed.
  • OPEN ACCESS
    Investigating the potential uptake of microplastic-derived carbon into a boreal lake food web using carbon-13 labelled plastic
    FACETS • Vol. 10 • pp. 1 - 9
    Microplastics degrade slowly over time, leaching carbon (C) that could be subsequently incorporated into aquatic food webs. Current estimates of microplastic degradation vary, and little is known about microplastic-derived C fate under natural environmental conditions. To investigate whether microplastics leach C that is subsequently incorporated into aquatic food webs, we added isotopically enriched microplastics to Lake 378 at the Experimental Lakes Area in Ontario, Canada. In an ∼1100 L limnocorral (in situ open-bottom enclosure), we added 99% 13C-labelled polystyrene (8–216 µm in longest dimension) at a nominal concentration of 3268 particles/L. A second limnocorral without microplastics served as a negative control. Monthly measurements of δ13C-DIC and δ13C-DOC in filtered water revealed no detectable leaching of 13C from the plastic. Compound-specific isotope analysis of δ13C in amino acids of bulk plankton and periphyton revealed a slight (0.5‰) enrichment in 13C, within the range of natural variability for these organisms. Under the natural conditions of temperate oligotrophic lakes, degradation of microplastics is likely a very slow process that was not possible to detect in this 4-month experiment. Future studies should focus on assessing degradation of microplastics under realistic field scenarios to improve estimates of degradation pathways and associated time scales.
  • OPEN ACCESS
    Naphthenic acid fraction compounds, produced by the extraction of bitumen from oil sands, alter survival and behaviour of juvenile yellow perch (Perca flavescens)
    FACETS • Vol. 9 • pp. 1 - 12
    We evaluated whether naphthenic acid fraction compounds (NAFCs) extracted from oil sand tailings adversely affect fish survival and behaviour. Following a before–after-control-impact design, we housed wild-caught juvenile yellow perch (Perca flavescens) in outdoor mesocosms to assess survival and behaviour under baseline conditions, then exposed fish to one of three treatments: negative control, 2 mg/L NAFC, or 15 mg/L NAFC. We performed behavioural assays (no-stimulus activity, food stimulus, and predator stimulus using a model bird) and assessed a comprehensive suite of endpoints (equilibrium losses, activity, shoaling, burst swimming, freezing, and space use). We found that exposure to 15 mg/L NAFCs substantially reduced fish survival and impaired fish equilibrium in all three behavioural tests. Furthermore, exposure to NAFCs impaired anti-predator behaviour: while the activity of control fish increased by two-fold in response to a predator stimulus, fish exposed to 2 or 15 mg/L NAFC did not change their activity levels after stimulation. No significant changes were observed in other behavioural endpoints. Overall, our findings suggest that a week-long exposure to NAFCs at concentrations commonly found in tailings ponds, constructed wetlands, and other mining-impacted waters may affect multiple facets of fish behaviour that could ultimately lead to reduced fitness in fish populations.
  • OPEN ACCESS
    A temporal record of microplastic accumulation in sediment cores of the Great Lakes, North America, reflects macroeconomic and regional influences
    FACETS • Vol. 9 • pp. 1 - 10
    Documented plastic pollution throughout the Laurentian Great Lakes system prompted investigation of microplastics (MPs) in sediment cores. We examined offshore sediment cores from Lake Huron (LH43) and Lake Ontario (403A) to understand temporal trends and changes in microplastic (MP) pollution in the size range 53 µm to 2 mm. MP abundances varied from 18.1 to 280.1 particles per g of dry weight sediment (N g−1 dw) in LH43, and 8.2–488.4 g−1 dw in core 403A. The 15 cm cores are equivalent to 56 years of accumulation in Lake Huron and 72 years of accumulation in Lake Ontario. Analysis of the two cores shows an increasing trend in MP accumulation from 1964 to 1989, which mirrors the global plastic production rate. Subsequent peaks and troughs in the MP abundance profiles reflect macroeconomic changes and regional controls. These results show how changing abundances of MPs in lake sediment cores can act as proxies for global perturbations in oil supply as well as national economic shifts.
  • OPEN ACCESS
    Historical gold mining increased metal(loid) concentrations in lake sediments from Nova Scotia, Canada
    FACETS • Vol. 9 • pp. 1 - 14
    Historical gold mining operations between the 1860s and 1940s have left substantial quantities of arsenic- and mercury-rich tailings near abandoned mines in remote and urban areas of Nova Scotia, Canada. Large amounts of materials from the tailings have entered the surface waters of downstream aquatic ecosystems at concentrations that present a risk to benthos. We used paleolimnological approaches to examine long-term trends in sedimentary metal(loid) concentrations, assess potential sediment toxicity, and determine if geochemical recovery has occurred at four lakes located downstream of three productive gold-mining districts. During the historical mining era, sedimentary total arsenic and mercury concentrations and enrichment factors increased substantially at all downstream lakes that received inputs from tailings. Similarly, chromium, lead, and zinc concentrations increased in the sediments after mining activities began and the urbanization that followed. The calculated probable effects of concentration quotients (PEC-Qs) for sediments exceeded the probable biological effects threshold (PEC-Q > 2) during the mining era. Although sedimentary metal(loid) concentrations have decreased for most elements in recent sediments, relatively higher PEC-Q and continued exceedance of Canadian Interim Sediment Quality Guidelines suggest that complete geochemical recovery has not occurred. It is likely that surface runoff from tailing fields, urbanization, and climate-mediated changes are impacting geochemical recovery trajectories.
  • OPEN ACCESS
    Ideal free distributions form across a regulatory boundary in the Northwest Atlantic Fisheries Organization (NAFO) Division 4X and 5Z groundfish fisheries
    FACETS • Vol. 9 • pp. 1 - 9
    We used isodars, developed from the ideal free distribution (IFD), to predict the distribution of fishing effort across regulatory boundaries in the south-western Scotian Shelf’s haddock fishery. Our analysis was focused around the boundary between Northwest Atlantic Fisheries Organization’s Divisions 4X and 5Z. While effort within 4X was related to the standardized catch value and effort experienced along the 4X–5Z boundary, most effort predictions across the boundary were also accurate. Accuracy of these cross-boundary isodars suggests that a high degree of movement across the boundary meets the IFD assumption of free movement and thus, effort on one side of the boundary is related to fishing success on the other side of the boundary. Fisheries management strategies should adopt a broad view that encompasses adjacent regulatory regions to understand where vessels may choose to fish when multiple regulatory regions are accessible. In fisheries where isodars describe effort distributions across a regulatory boundary, the relative abundance of the underlying fish population could be better indicated by effort distribution among regulatory regions than by catch rates.
  • OPEN ACCESS
    River influence on mercury bioaccumulation in the coastal food web of Eeyou Istchee, James Bay, Canada
    FACETS • Vol. 9 • pp. 1 - 13
    Spatial patterns of bioaccumulated mercury were evaluated in coastal marine food webs of east Hudson Bay and east James Bay in the boreal subarctic of Canada. Two marine species, blue mussels (Mytilus edulis) and common eider ducks (Somateria mollissima) that consume mussels, were collected by a regional community-based monitoring network established in five communities. Stable isotope tracers (carbon, nitrogen, sulfur, and mercury) were measured to evaluate environmental drivers of mercury spatial patterns. Mercury concentrations of blue mussels and common eiders were twofold and fivefold higher, respectively, on the James Bay coast near the community of Chisasibi compared to sites in east Hudson Bay. Liver and muscle mercury concentrations of eiders from James Bay are among the highest values reported for the circumpolar subarctic and Arctic. Multiple lines of evidence (mercury spatial patterns, crustal elements in blue mussels, and mercury isotope values of common eiders) suggest elevated mercury in the coastal food web of east James Bay may be due to mercury loading from the La Grande River, which drains one of the largest hydroelectric developments in the world. These findings highlight the importance of further research on environmental processes linking large rivers to mercury bioaccumulation in northern coastal food webs.
  • OPEN ACCESS
    Assessing climate change vulnerability in Canadian marine conservation networks: implications for conservation planning and resilience
    FACETS • Vol. 9 • pp. 1 - 15
    Marine protected areas (MPAs) are critical in safeguarding biodiversity and ecosystem functions under climate change. The long-term effectiveness of these static conservation measures will depend on how well they represent current and future ocean changes. Here, we use the Climate Risk Index for Biodiversity to assess the vulnerability representation of marine ecosystems within the Canadian marine conservation network (CMCN) under two divergent emissions scenarios. We found that MPAs best represent climate vulnerability in Atlantic Canada (85% representativity overall, and 93% in the Gulf of Saint Lawrence under low emissions), followed by the Pacific (78%) and Arctic (63%; lowest in the Eastern Arctic (41% under high emissions) regions). Notably, MPAs with lower climate vulnerability are proportionally overrepresented in the CMCN. Broad-scale geographic targets employed in the Scotian Shelf-Bay of Fundy network planning process achieve over 90% representativity of climate vulnerabilities, underscoring the importance of ensuring habitat representativity and geographic distribution in conservation planning to enhance climate resilience, even if not explicitly prioritized. Moving towards Canada’s target to protect 30% of its waters by 2030, prioritizing representativity and designation of MPAs in currently underrepresented climate-vulnerable regions may be crucial to enhancing the resilience of the CMCN amidst an ever-changing climate.
  • OPEN ACCESS
    Evaluating the design of the first marine protected area network in Pacific Canada under a changing climate
    FACETS • Vol. 9 • pp. 1 - 18
    Marine protected area (MPAs) networks can buffer marine ecosystems from the impacts of climate change by allowing species to redistribute as conditions change and by reducing other stressors. There are, however, few examples where climate change has been considered in MPA network design. In this paper, we assess how climate change considerations were integrated into the design of a newly released MPA network in the Northern Shelf Bioregion in British Columbia, Canada, and then evaluate the resulting network against projected physical and biogeochemical changes and biological responses. We found that representation, replication, and size and spacing recommendations integrated into the design phase were met in most cases. Furthermore, despite varying degrees of projected changes in temperature, dissolved oxygen, and aragonite saturation across the MPA network, suitable habitat for demersal fish species is projected to remain in the network despite some redistribution among sites. We also found that mid-depth MPAs are particularly important for persistence, as fish are projected to move deeper to avoid warming in shallower areas. Our results highlight that a representative MPA network with adequate replication, that incorporates areas of varying climate change trajectory, should buffer against the impacts of climate change.
  • OPEN ACCESS
    Estimating size-at-harvest from Indigenous archaeological clamshell assemblages in Coastal British Columbia
    FACETS • Vol. 9 • pp. 1 - 15
    Shellfish have supported Indigenous lifeways on the Pacific Coast of North America for millennia. Despite the ubiquity of clamshells in archaeological sites, shell size measurements are rarely reported due to a lack of applicable basis for generating size estimates from fragmentary remains. We present a linear regression-based method for determining shell length from hinge and umbo measurements of littleneck (Leukoma staminea; n = 239), butter (Saxidomus gigantea; n = 274), and horse (Tresus nuttallii; n = 92) clams using both contemporary and archaeological shells collected from three regions in coastal British Columbia, Canada. We examine the accuracy of these size estimations, which indicate that 83%–97% of the variability in dorsal shell length is predicted by umbo thickness and hinge length. Hinge length generated higher R2 values yet exhibited greater intra- and inter-observer error. While the predicted dorsal length for each species differed by region, this size difference was smaller than intra- and inter-observer error, suggesting broad applicability for these simple measurements. We applied these formulae to a Tseshaht First Nation archaeological clamshell assemblage (n = 488) on western Vancouver Island spanning 3000 years and observed profiles that resemble contemporary legal size limits, which suggests the sustained use and maintenance of local shellfisheries. The accuracy of these regression models for determining shell length from fragments highlights the utility of this approach as a basis for assessing past shellfish management practices.
  • OPEN ACCESS
    Seasonal patterns and key chemical predictors of dissolved greenhouse gases in small prairie pothole ponds
    FACETS • Vol. 9 • pp. 1 - 18
    Shallow ponds can provide ideal conditions for production of greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), and thus are important to include in global and regional GHG budgets. The Canadian Prairie Pothole Region contains millions of shallow natural ponds, and we investigated GHG dynamics in 145 ponds across the region. Ponds were consistently supersaturated with CH4, often supersaturated with CO2 (57% occurrence), and often undersaturated with N2O (65% occurrence). Spring measurements showed higher N2O saturation (p = 0.0037) than summer, while summer had higher CH4 (p < 0.001) and CO2 (p = 0.023) saturation than spring. Ponds exhibited large physicochemical variation, yet sulfate concentration and pH were strong predictors of dissolved CH4 and CO2, respectively. No predictor was identified for N2O. The link between sulfate and CH4 has important implications as dissolved CH4 in low sulfate (<178 mg L−1) systems was much more responsive to changes in temperature. This research fills an important knowledge gap about the GHG dynamics of prairie pothole ponds and the role of water chemistry for diffuse GHG release. Our work can also be used in ongoing efforts to describe ecosystem services (or disservices) assigned to ponds in this agriculture-dominated region.
  • OPEN ACCESS
    Climate bottlenecks off Newfoundland and Labrador for Atlantic cod in relation to eastern Canadian marine protected areas
    FACETS • Vol. 9 • pp. 1 - 31
    Climate change presents challenges for marine area-based conservation measures through altered habitat and associated species range shifts. We conducted statistical downscaling for the eastern Canadian coastal domain over a range of global climate models, focusing on habitat suitability for Atlantic cod (Gadus morhua), a numerically depressed, but ecologically, economically, and culturally important species in this region. We examined cod egg survival, juvenile growth, and spawning habitat suitability, combining these into one habitat index to compare within-closure habitat suitability for multiple life stages through time. Areas of high cod egg habitat suitability are projected to shift northward and increase across all area closures studied, while optimum juvenile habitat shifts north and eastward, increasing in almost all closures except the south. Spawning habitat as a function of temperature and oxygen will likely decrease through time across the entire region, but less in northern locations. Overall cod habitat is forecasted to decline in the south of the region while increasing at central and northern latitudes, highlighting the importance of existing and developing northern shelf area closures. While warming will bring temperatures closer to optimum levels for cod in this cold-water system, oxygen limitation will become more prevalent in the south of the region and should be monitored as an important ocean health indicator.
  • OPEN ACCESS
    The long-term effects of water resource development on blood mercury levels and the trophic ecology of Namew (lake sturgeon, Acipenser fulvescens)
    FACETS • Vol. 9 • pp. 1 - 13
    Water resource development can alter the movement and ecology of sturgeons. We studied total (THg) and methylmercury concentrations in whole blood sampled non-lethally from namew (Moose Cree L-dialect, lake sturgeon, Acipenser fulvescens), an endangered and culturally important subsistence fish. Namew were sampled from two tributaries within the Moose Cree Homeland: the Lower Mattagami River (an impacted system with four hydroelectric generating stations) and the North French River (a reference system that is free-flowing system with no development). Results indicated namew from the North French River had higher blood [THg] than those from the Mattagami River. Further modeling showed that trophic position was the primary driver of these differences, with North French namew having the highest nitrogen isotope ratios. Based on further isotope modeling, crayfish were major components of namew diet at all sites, while other prey items differed between sites. Specifically, namew with unobstructed access to the lower watershed had notably more enriched isotope values when compared to the freshwater benthic macroinvertebrates sampled, implying that other prey not captured herein may contribute to their diets and [THg]. Overall, we found differences in namew’s trophic ecology but no elevation in blood mercury levels at a site impacted by hydroelectric operations 60+ years post-impoundment.
  • OPEN ACCESS
    Modelling the dispersion of infectious salmon anemia virus from Atlantic salmon farms in the Quoddy Region of New Brunswick, Canada and Maine, USA
    FACETS • Vol. 9 • pp. 1 - 19
    Pathogen dispersal from infected aquaculture sites into the surrounding ocean poses risks of infection to wild and farmed species, but is difficult to predict. This study aimed to build a framework using an ocean circulation and a particle tracking model in conjunction with a dynamic infection model and a virus inactivation model to simulate the dispersal of the infectious salmon anemia virus (ISAV) from Atlantic salmon farms. Simulated particles were released from hypothetically infected farms and advected by modelled currents. Inactivation of viral cohorts by ambient ultraviolet radiation and natural microbial communities was simulated during advection. Simulations showed that ISAV concentration varied spatiotemporally with the progression of the outbreak, current speed and direction, tidal elevation amplitude, and environmental decay. Connectivity among aquaculture sites varied in relation to seaway distances, though simulations showed that connectivity can also be asymmetrical between farm sites. Sensitivity analyses showed that the dispersal of ISAV was moderately sensitive to uncertainty associated with the viral decay model, highlighting the importance of obtaining accurate estimates of inactivation rates of ISAV. This framework provides an approach to simulate waterborne viral transmission that considers the biology and epidemic features of significance for pathogens and the dynamic conditions of the ocean.
  • OPEN ACCESS
    Effect of acclimation temperature on thermal tolerance between American lobster (Homarus americanus) collected in different lobster fishing areas in Atlantic Canada
    FACETS • Vol. 9 • pp. 1 - 9
    The American lobster fishery is the most economically significant commercial fishery in Atlantic Canada and takes place in waters that are warming due to climate change. Lobster are poikilotherms that tolerate a wide range of seasonal temperatures with an optimal range of 12–18 °C. Lobster in the Canadian Maritimes may be naturally acclimated to a wide range of temperatures and thus, could have a wide range of thermal tolerance that may be distinct across regions. The present study used non-invasive open-source tools to explore differences in thermal tolerance in real time between geographically separated lobster populations from around the Canadian Maritimes. Lobsters were acquired from six lobster fishing areas in the Canadian Maritimes and acclimated to either warm (15 °C) or cold (5 °C) water for two weeks before the onset of thermal trials. Geographic origin was not a significant predictor of estimated thermal maximum, while acclimation temperature was a significant predictor. These results suggest that thermal tolerance is more strongly linked to acclimation temperature than to geographic region.
  • OPEN ACCESS
    Transport does not influence maximum metabolic rate or thermal tolerance of endangered redside dace (Clinostomus elongatus)
    FACETS • Vol. 9 • pp. 1 - 9
    Reintroduction is an important tool in the conservation and recovery of aquatic species at risk. However, components of the reintroduction process such as transportation have the potential to induce physiological stress and the extent to which preparatory techniques can mitigate this stress is poorly understood in small-bodied fishes. To address this concern, we studied the effect of transport on two fitness-related performance measures: maximum metabolic rate and thermal tolerance in redside dace (Clinostomus elongatus), an imperilled small-bodied stream fish native to eastern North America. Prior to transportation, we manipulated the body condition of redside dace over a 12-week period, by providing either low (1% of their total body mass) or high (2% of their total body mass) rations. The goal of this manipulation was to influence body condition, as higher body condition can enhance physiological performance. Subsequently, redside dace were transported for varying durations: 0, 3, and 6 h. Following transportation, we measured maximum metabolic rate (µmol/h) and thermal tolerance (CTmax, °C). Our results indicate that neither transport nor body condition had a significant effect on maximum metabolic rate or thermal tolerance (CTmax). These findings provide preliminary evidence that redside dace can physiologically tolerate transport based on the endpoints measured and this information may possibly be extended to other small-bodied fish, for which information is lacking.
  • OPEN ACCESS
    The effect of riffle restoration on the recovery of endangered Nooksack Dace (Rhinichthys cataractae sp. cataractae)
    FACETS • Vol. 9 • pp. 1 - 15
    The Nooksack Dace (Rhinichthys cataractae sp. cataractae) is a federally endangered riffle specialist endemic to the lower Fraser Valley of British Columbia, Canada, with historic population declines associated with riffle loss from stream dredging, channelization, and excessive sediment inputs. To assess the effectiveness of riffle restoration as a recovery strategy, gravel and cobble riffles were constructed in two replicate tributaries of the Nooksack River as a before-after-control-impact experiment, measuring dace abundance, substrate composition, and invertebrate biomass before and one year after restoration. Nooksack Dace density increased significantly in cobble (but not gravel) treatments relative to control riffles. Dace abundance was strongly associated with increased availability of interstitial refuges rather than substrate effects on invertebrate prey abundance, suggesting that interstitial space limits adult dace abundance. Young-of-the-year dace were not observed in one of the two restored streams despite riffle restoration, indicating increased dace density due to aggregation in higher-quality restored riffles. This recruitment limitation indicates persistence of a population bottleneck at an early life history stage that is not addressed by successful restoration of adult riffle habitat.
  • OPEN ACCESS
    Bull kelp (Nereocystis luetkeana) growth rates as climate stress indicators for Canada’s Pacific coast
    FACETS • Vol. 9 • pp. 1 - 19
    Primary producers’ growth rates are ideal bioindicators of changing climate due to their sensitivity to environmental conditions. On the Central Coast of British Columbia, we assessed growth rates of Nereocystis luetkeana, a canopy-forming annual kelp, by assessing baseline variability in growth rates and their response to environmental conditions of over 600 individuals and across three sites (2016–2019). Optimal growth rates for blades and stipes (∼13–14 cm/day) occurred within a narrow range of local environmental conditions. Growth decreased at temperatures > 10 °C, below 1 µm/L nitrate concentration, and surface light availability reduced blade growth at low and high levels (daily light integral or DLI <20 and >40 mol/m2/day). Spatiotemporal variability in these environmental drivers co-occurred with differences in growth rates, suggesting that local conditions strongly influenced growth. In particular, temperature and nutrients were un-coupled seasonally in this region, with more variable responses in growth over the primary growing season (May to September). Overall, the sensitivity of the growth rates of this annual kelp to changing climatic conditions suggests that it is a useful bioindicator for management and marine planning efforts (e.g., restoration and aquaculture) across its species range and provides a feasible metric for monitoring.
  • OPEN ACCESS
    Bigmouth Buffalo (Ictiobus cyprinellus) migratory behaviour and seasonal home range overlap are functions of geographic space in a fragmented riverscape
    FACETS • Vol. 9 • pp. 1 - 17
    In temperate rivers, where environmental conditions vary seasonally, many fishes migrate among summer, spawning, and winter habitats. Dams disrupt these migrations, limiting access to habitat and potentially affecting populations. Bigmouth Buffalo (Ictiobus cyprinellus) is a species of fish with at-risk populations in central Canada. The impact of dams on the extent of Bigmouth Buffalo migration and the overlap between summer and winter home ranges is unknown. Here, we assessed the migratory history of 80 Bigmouth Buffalo tagged with acoustic transmitters in the Red River (USA and Canada), a large binational waterway regulated by semi-passable dams. We sought to understand when and why Bigmouth Buffalo migrate, and how river use varies seasonally. Following more than 6 years of data collection, we found that the degree and probability of overlap between winter and summer home ranges varied by river section between barriers. Importantly, overlap was lowest in the longest continuous river section where well-defined migratory behaviours were observed. The results of this study reveal previously unknown details about Bigmouth Buffalo migration, demonstrate the consequences of river fragmentation on geographic space use, and highlight the importance of river connectivity to fish migration.
  • OPEN ACCESS
    Marine ecozones represent a major gap in Canadian DNA barcoding efforts
    FACETS • Vol. 9 • pp. 1 - 11
    Because of Canada’s large size, it is impractical to obtain a comprehensive perspective on biotic change through morphological approaches. DNA metabarcoding offers a potential path, but its application requires access to a well-parameterized DNA barcode reference library. This study presents the current state of DNA barcode coverage for Canadian animals, highlighting progress, identifying gaps, and providing recommendations for future research. Our analysis indicates that many of the known species (100 000 terrestrial and 6000 marine) in the Canadian fauna possess DNA barcode coverage, but there are important gaps geographically and taxonomically. We summarize DNA barcode coverage for the species in freshwater, marine, and terrestrial environments by ecoregion, finding that 95.6% of the 2.3 million Canadian barcode records derive from terrestrial ecosystems. Although the density of barcode records per 100 km² is 13x higher for terrestrial than aquatic environments (22.4 vs. 1.7), coverage for 58% of marine species is available (54% for annelids, 52% for arthropods, 88% for chordates, 39% for echinoderms, and 46% for molluscs). By revealing data-deficient areas and taxonomic groups, this study offers a roadmap for expanding the DNA barcode library for the Canadian fauna as an essential foundation for the scalable biosurveillance initiatives that inform biodiversity conservation efforts.
  • OPEN ACCESS
    A One Health perspective on recreational fisheries
    FACETS • Vol. 9 • pp. 1 - 9
    Recreational fisheries involve an intimate connection between people, individual fish, and the environment. Recreational fishers and their health crucially depend on healthy fish and ecosystems. Similarly, fish and ecosystems can be impacted by the activities of people including recreational fishers. Thus, amplified by the global interest in recreational fishing, we posit that recreational fishing is particularly suited as an empirical system to explore a One Health perspective, with a goal of creating pathways to better manage such socio-ecological systems for the benefit of people, fish, and the environment. Although zoonoses are uncommon in fishes, fish can carry pathogens, biotoxins, or contaminants that are harmful to people. When captured and released, fish can experience stress and injuries that may promote pathogen development. Similarly, when humans contribute to environmental degradation, not only are fish impacted but so are the humans that depend on them for nutrition, livelihoods, culture, and well-being. Failure to embrace the One Health perspective for recreational fisheries has the potential to negatively impact the health of fish, fisheries, people, society, and the aquatic environment—especially important since these complex social–ecological systems are undergoing rapid change.
  • OPEN ACCESS
    Recent and projected climate change–induced expansion of Atlantic halibut in the Northwest Atlantic
    FACETS • Vol. 8 • pp. 1 - 14
    With the influence of climate change on marine systems expanding, climate adaptation will be fundamental for the future of fisheries management. An exponential increase in Atlantic halibut Hippoglossus hippoglossus landings over the past decade has coincided with warming ocean temperatures. Here, we explore how historical changes in abundance have been linked to changing thermal habitat conditions and project trends with a warming climate under different emissions scenarios. From 1990 to 2018, available thermal habitat increased by 11.6 ± 7.35% and growing degree days have increased by 13.5 ± 7.86 °C·days across the region. With warming, the probability of occurrence is projected to increase up to 20.5% in Canada by 2085 under RCP 8.5 for Atlantic halibut. Our results suggest that shifting patterns of halibut distribution and abundance are linked to thermal conditions and that continued warming will likely continue to enhance habitat conditions, leading to increased abundance in the Canadian range. Collectively, these results illustrate the influence of shifting environmental conditions on population dynamics and emphasize the importance of adaptive management practices in a dynamic future climate.
  • OPEN ACCESS
    A methodology for quantifying and characterizing litter from trash capture devices (TCDs) to measure impact and inform upstream solutions
    FACETS • Vol. 8 • pp. 1 - 12
    Trash capture devices (TCDs) are a rapidly evolving tool for municipal governments, non-governmental organizations, and industries to divert litter from our waterways. Here, we introduce protocols to initiate trash trapping projects to quantify and characterize captured anthropogenic litter based on a case study using Seabins. In addition, we have introduced a network for global data collection via TCDs. Our first protocol is a visual audit of the potential site to inform the type and location for TCD deployment. Our next two protocols quantify and characterize the litter captured by TCDs: (1) a simple protocol intended for daily monitoring and (2) a detailed protocol to characterize and quantify all large debris (>3 cm) and a subset of the small debris (2 mm–3 cm) caught in the devices. Using Seabins in the Toronto Harbour to test our methodology, we found that our subsampling methodology has a 6.9% error rate. Over a 19-week period, the Seabins captured ∼85 000 pieces of small debris. Our study highlights the utility of TCDs and proposes methods to realize this utility globally. TCDs should become more widespread and utilized as a triple threat: a cleanup tool, a data collection tool, and a platform for outreach and education.
  • OPEN ACCESS
    Incorporating protected areas into global fish biomass projections under climate change
    FACETS • Vol. 8 • pp. 1 - 16
    The world has set ambitious goals to protect marine biodiversity and improve ocean health in the face of anthropogenic threats. Yet, the efficiency of spatial tools such as marine reserves to protect biodiversity is threatened as climate change shifts species distributions globally. Here, we investigate the ability of global marine reserves to protect fish biomass under future climate change scenarios. Moreover, we explore regional patterns and compare worlds with and without marine reserves. We rely on computer modeling to simulate an utopian world where all marine reserves thrive and ocean governance is effective. Results suggest that climate change will affect fish biomass in most marine reserves and their surrounding waters throughout the 21st century. The biomass change varies among regions, with tropical reserves losing biomass, temperate ones gaining, and polar reserves having mixed effects. Overall, a world with marine reserves will still be better off in terms of fish biomass than a world without marine reserves. Our study highlights the need to promote climate resilient conservation methods if we are to maintain and recover biodiversity in the ocean under a changing world.
  • OPEN ACCESS
    Evaluating community science sampling for microplastics in shore sediments of large river watersheds
    FACETS • Vol. 8 • pp. 1 - 15
    A community science project in the Ottawa River Watershed in Canada interacted with an existing volunteer base to collect sediment from 68 locations in the watershed over approximately 750 km. Ninety-one percent of the distributed kits were returned with 42 volunteers taking part in the project. After analysis, particle concentrations were relatively low compared to previous freshwater microplastic sediment research, with contributing factors including (but not limited to) the large size of the watershed, a lower population base compared to other researched freshwater watersheds, the relative size and discharge of the Ottawa River and the large seasonal fluxes experienced in the river basin. Utilising community science for sampling large freshwater watersheds demonstrated its advantages in the research, especially spatially. However, careful consideration to research design and implementation is essential for community science projects examining microplastics in freshwater sediments. Research teams should ensure they are responsible for strict quality assurance and quality control protocols, especially in the laboratory with sample preparation and processing. Nonetheless, community science is potentially an extremely useful approach for researchers to use for microplastic sampling projects over large spatial areas.
  • OPEN ACCESS
    The reproducibility of remotely piloted aircraft systems to monitor seasonal variation in submerged seagrass and estuarine habitats
    FACETS • Vol. 8 • pp. 1 - 22
    Seasonal variation in seagrass growth and senescence affects the provision of ecosystem services and restoration efforts, requiring seasonal monitoring. Remotely piloted aircraft systems (RPAS) enable frequent high-resolution surveys at full-meadow scales. However, the reproducibility of RPAS surveys is challenged by varying environmental conditions, which are common in temperate estuarine systems. We surveyed three eelgrass (Zostera marina) meadows in Newfoundland, Canada, using an RPAS equipped with a three-color band (red, green, blue [RGB]) camera, to evaluate the seasonal reproducibility of RPAS surveys and assess the effects of flight altitude (30–115 m) on classification accuracy. Habitat percent cover was estimated using supervised image classification and compared to corresponding estimates from snorkel quadrat surveys. Our results revealed inconsistent misclassification due to environmental variability and low spectral separability between habitats. This rendered differentiating between model misclassification versus actual changes in seagrass cover infeasible. Conflicting estimates in seagrass and macroalgae percent cover compared to snorkel estimates could not be corrected by decreasing the RPAS altitude. Instead, higher altitude surveys may be worth the trade-off of lower image resolution to avoid environmental conditions shifting mid-survey. We conclude that RPAS surveys using RGB imagery alone may be insufficient to discriminate seasonal changes in estuarine subtidal vegetated habitats.
  • OPEN ACCESS
    Balancing privacy with access to information for commercial fisheries data: A critical review of Fisheries and Oceans Canada’s “rule of five” policy
    FACETS • Vol. 8 • pp. 1 - 11
    Although Canada’s oceans are a public resource, commercial fisheries data are routinely withheld from researchers and the general public by Fisheries and Oceans Canada (DFO) due to privacy obligations. However, data can be released if considered sufficiently de-personalized through an internal guideline called the “rule of five,” under which data sources are aggregated to a threshold of five to allow for data publication or disclosure. This article provides an overview of the “rule of five,” summarizes key legislative provisions that have bearing on the “rule” and potential for its reform, and discusses the findings from two tools used to collect information on the “rule” and its use in Canada: (1) an Access to Information and Privacy request and (2) an anonymous survey conducted to evaluate the impacts of the “rule” on various stakeholders. The “rule of five” is not mandatory but rather represents a conservative approach to access to information that can be detrimental to independent researchers and the public interest in transparent fisheries data. The article concludes with recommendations to further a rebalancing of privacy and access to information, including emphasizing existing legislative exemptions that could allow for data disclosure when the “rule of five” is not met.
  • OPEN ACCESS
    Saskatchewan Condition Assessment of Lotic Ecosystems (SCALE): A multivariate tool for assessing the integrity of Northern Great Plains wadeable rivers and streams
    FACETS • Vol. 8 • pp. 1 - 31
    Human access to surface water resources in the Northern Great Plains (NGP) is challenged by availability and quality, and ecosystem health objectives for these characteristics have not been well developed. Here, we present a predictive multivariate model using the reference condition approach to inform goals for ecosystem health assessment. Benthic communities and abiotic variables were collected at 280 potential reference sites and 8 test sites, and of these, reference sites with least amount of human activity (n = 83) were classified into three community groups and summary metrics. Discriminant function analysis and cross-validation determined that stream order and ecoregion predicted 68.7% of the sites correctly, thus enabling comparison of sites with unknown condition to reference site groups. We then evaluated metrics through Test Site Analysis and stressor gradient analysis in each biological group. Beetle and amphipod fauna were found to be important for condition assessment in addition to traditional metrics of species richness, abundance, detritivory, Ephemeroptera/Plecoptera/Trichoptera dominance, and assemblage composition. These results provide least disturbed reference condition and ecological insights into land use impacts in the NGP. Ultimately, this model is an effective tool for evaluating biotic condition, enables prioritizing river management strategies, and can quantify the efficacy of mitigation measures.
  • OPEN ACCESS
    A prospective framework to support climate-adaptive fisheries in Canada
    FACETS • Vol. 8 • pp. 1 - 15
    Climate change affects virtually all marine life and is increasingly a dominant concern for fisheries, reinforcing the need to incorporate climate variability and change when managing fish stocks. Canada is expected to experience widespread climate-driven impacts on its fisheries but does not yet have a clear adaptation strategy. Here, we provide an overview of a project we are developing, the Climate Adaptation Framework for Fisheries, to address this need and support climate adaptation in Canadian marine fisheries. The framework seeks to quantitatively and flexibly evaluate species, fishing infrastructure, and the management and operation of fisheries to assess climate vulnerability comprehensively and provide outputs that can support climate adaptation planning across different sectors, agencies, and stakeholders. This new framework should allow future climate scenarios to be evaluated and identify actionable climate vulnerabilities related to the management of fisheries, creating a systematic approach to supporting climate adaptation in Canada’s fisheries.
  • OPEN ACCESS
    Climate change, species thermal emergence, and conservation design: a case study in the Canadian Northwest Atlantic
    FACETS • Vol. 8 • pp. 1 - 16
    Marine Protected Areas (MPAs) are conservation tools that promote biodiversity by regulating human impacts. However, because MPAs are fixed in space and, by design, difficult to change, climate change may challenge their long-term effectiveness. It is therefore imperative to consider anticipated ecological changes in their design. We predict the time of emergence (ToE: year when temperatures will exceed a species’ tolerance) of 30 fish and invertebrate species in the Scotian Shelf-Bay of Fundy draft network of conservation areas based on climate projections under two contrasting emission scenarios (RCP 2.6 and RCP 8.5). We demonstrate a strong Southwest-to-Northeast gradient of change under both scenarios. Cold water-associated species had earlier ToEs, particularly in southwesterly areas. Under low emissions, 20.0% of habitat and 12.6% of species emerged from the network as a whole by 2100. Under high emissions, 51% of habitat and 42% of species emerged. These impacts are expected within the next 30–50 years in some southwestern areas. The magnitude and velocity of change will be tempered by reduced emissions. Our identification of high- and low-risk areas for species of direct and indirect conservation interest can support decisions regarding site and network design (and designation scheduling), promoting climate resilience.
  • OPEN ACCESS
    Structuring forces of intertidal infaunal communities on the northern coast of British Columbia, Canada: assessing the relative importance of top-down, bottom-up, middle-out, and abiotic variables
    FACETS • Vol. 8 • pp. 1 - 14
    While trophic and habitat-related abiotic variables (predation, competition, tolerance, etc.) are known to influence community structure in many ecosystems, some systems appear to be only minimally influenced by these variables. Sampling multiple tidal flat communities in northern BC, Canada, we investigated the relative importance of top-down and middle-out (mesopredators) variables, competition for resources (bottom up), and abiotic variables in structuring an infaunal community (invertebrates living in sediment). Similar to previous studies on mudflats in the Bay of Fundy (also at a north temperate latitude), we determined that these variables accounted for a minor (0%–9%) proportion of the observed variation in this infaunal community, suggesting that these variables play a small role in structuring this community. Based on the results of our study and in combination with previous experiments on infaunal recovery patterns post disturbance, we posit that the main factors influencing these infaunal communities likely operate at a scale of sites (kilometres) and(or) plot (metres or less) but not transects (10–100 m within site). Candidate forces structuring these intertidal communities that need future examination include regional species pools and the variables that affect these pools, sediment biogeochemistry, and disturbance/recovery history of a site. The similarity of our Pacific coast findings to those from the north temperate Atlantic coast suggests some similarity in the processes structuring these distinct infaunal communities.
  • OPEN ACCESS
    One informs the other: Unionid species at risk and benthic macroinvertebrate community monitoring data are complementary
    FACETS • Vol. 8 • pp. 1 - 13
    Benthic macroinvertebrate communities, which include unionid freshwater mussels, enhance the health of river ecosystems. Human impacts have driven declines within freshwater mussel communities and due to their complex life cycles, mussel recovery efforts are complex. In Canada, conservation of imperiled species has focused on biodiversity hotspots such as the Sydenham River in the Laurentian Great Lakes Basin. In practice, species conservation and habitat monitoring are siloed between federal agencies and local conservation authorities, limiting the potential for alignment of conservation policy and practice. Here we bring together federal, local, and our own survey data to explore patterns of co-occurrences between mussel species and other macroinvertebrate taxa to explore the extent to which knowledge of one benthic community informs the other. Mussel communities (species richness, community composition) differed between sites where imperiled mussel species were present and/or absent. Benthic macroinvertebrate metrics (e.g., family richness, percent Ephemeroptera, Plecoptera, and Trichoptera taxa) and specific indicator taxa were correlated with mussel species richness and the presence of imperiled mussel species. We show that benthic macroinvertebrate diversity indicators provided insight into imperiled species occurrences that warrant further investigation. These findings underscore support for coordinated watershed monitoring efforts and could be crucial for more successful freshwater mussel conservation.
  • OPEN ACCESS
    On the troubling use of plastic ‘habitat’ structures for fish in freshwater ecosystems – or – when restoration is just littering
    FACETS • Vol. 8 • pp. 1 - 19
    The creation and deployment of plastic structures made out of pipes and panels in freshwater ecosystems to enhance fish habitat or restore freshwater systems have become popularized in some regions. Here, we outline concerns with these activities, examine the associated evidence base for using plastic materials for restoration, and provide some suggestions for a path forward. The evidence base supporting the use of plastic structures in freshwater systems is limited in terms of ecological benefit and assurances that the use of plastics does not contribute to pollution via plastic degradation or leaching. Rarely was a cradle-to-grave approach (i.e. the full life cycle of restoration as well as the full suite of environmental consequences arising from plastic creation to disposal) considered nor were decommissioning plans required for deployment of plastic habitats. We suggest that there is a need to embrace natural materials when engaging in habitat restoration and provide more opportunities for relevant actors to have a voice regarding the types of materials used. It is clear that restoration of freshwater ecosystems is critically important, but those efforts need to be guided by science and not result in potential long-term harm. We conclude that based on the current evidence base, the use of plastic for habitat enhancement or restoration in freshwater systems is nothing short of littering.
  • OPEN ACCESS
    Canada's marine carbon sink: an early career perspective on the state of research and existing knowledge gaps
    FACETS • Vol. 8 • pp. 1 - 21
    Improving our understanding of how the ocean absorbs carbon dioxide is critical to climate change mitigation efforts. We, a group of early career ocean professionals working in Canada, summarize current research and identify steps forward to improve our understanding of the marine carbon sink in Canadian national and offshore waters. We have compiled an extensive collection of reported surface ocean air–sea carbon dioxide exchange values within each of Canada's three adjacent ocean basins. We review the current understanding of air–sea carbon fluxes and identify major challenges limiting our understanding in the Pacific, the Arctic, and the Atlantic Ocean. We focus on ways of reducing uncertainty to inform Canada's carbon stocktake, establish baselines for marine carbon dioxide removal projects, and support efforts to mitigate and adapt to ocean acidification. Future directions recommended by this group include investing in maturing and building capacity in the use of marine carbon sensors, improving ocean biogeochemical models fit-for-purpose in regional and ocean carbon dioxide removal applications, creating transparent and robust monitoring, verification, and reporting protocols for marine carbon dioxide removal, tailoring community-specific approaches to co-generate knowledge with First Nations, and advancing training opportunities for early career ocean professionals in marine carbon science and technology.
  • OPEN ACCESS
    Barriers to implementation of dynamic reference points in fisheries management
    FACETS • Vol. 8 • pp. 1 - 10
    Fish populations are dynamic; their productivity depends on the environment, predator and prey interactions, and fisheries harvest rates. Failure to account for these factors in fisheries science and management can lead to a misestimation of stock dynamics and productivity, resulting in overexploitation or forgone fisheries yield. Using an online survey, we asked fisheries scientists, industry stakeholders, Indigenous partners, and non-governmental organizations whether changing ecosystem productivity was a problem in their experience, how often dynamic approaches to fisheries reference points have been adopted, what methods had been used, and what fisheries they had been applied to. Changing fisheries or ecosystem productivity was reported as an issue by 96% of respondents; however, 74% of respondents said they had never seen dynamic reference points implemented, 16% said in very few instances, while 10% said frequently. The most common barriers to implementation of dynamic approaches in fisheries management were institutional inertia and uncertainty about whether a change in productivity was lasting. We discuss trade-offs between fisheries management performance and stability.
  • OPEN ACCESS
    British Columbia freshwater salmon hatcheries demonstrate minimal contribution to piscine orthoreovirus (PRV) regional occurrence with no evidence for nonendemic strain introductions
    FACETS • Vol. 8 • pp. 1 - 9
    Piscine orthoreovirus genotype 1 (PRV-1) is a common virus in farmed and wild salmon in the northeastern Pacific Ocean. Its regional occurrence in freshwater is far less clear. From 2019 to 2021, tissues of 5619 juvenile anadromous salmon (primarily Atlantic, Chinook, and coho) sampled from 12 commercial and 27 enhancement British Columbia hatcheries during 83 sampling events were screened for PRV-1 prior to seawater entry. More than 2200 (∼40%) were also screened using a Pan-PRV assay targeting all known PRV genotypes. PRV-1 was detected in four coho salmon at two freshwater enhancement facilities and in one Chinook salmon at a commercial facility. Partial (S1 segment) genome sequencing identified detections to be of the PRV-1 subgenotype endemic to the northeastern Pacific. PRV-1 was not detected (5611 individuals; 99.9%) or test results were inconclusive (3 individuals; 0.05%) for all remaining samples screened for PRV-1. PRV-2 and PRV-3 were not detected using the Pan-PRV assay. It is concluded that commercial and enhancement freshwater hatcheries of British Columbia contribute minimally to the prevalence and persistence of PRV-1 in anadromous salmon of the northeastern Pacific, and these hatcheries appear not to have contracted or participated in the distribution of nonendemic forms of PRV in recent years.
  • OPEN ACCESS
    Baseline composition, quantity, and condition of bycatch in the southern Gulf of St. Lawrence spring and summer American lobster fisheries
    FACETS • Vol. 8 • pp. 1 - 17
    The impact of the southern Gulf of St. Lawrence American lobster (Homarus americanus) fishery on species bycatch is currently unknown. The composition of the incidental catch, both nonharvestable lobster (by fisheries regulations) and nonlobster species, was systematically collected over the 2015 spring and summer fishing seasons. A total of 51 948 (7147 were nonlobster taxa) individual organisms weighing 13 987.60 kg (1223.91 kg of nonlobster taxa) were captured as bycatch during 73 fishing trips. By weight per trip, the most common lobster bycatch were undersized male and females, and the highest nonlobster species catch were Atlantic rock crab (Cancer irroratus). A semiquantitative assessment of injury and vitality was applied to bycatch as a proxy for discard mortality. The majority of the individuals assessed for visible injury were deemed uninjured (98% both fish and invertebrates); however, postrelease mortality was not measured. A smaller study in 2019 corroborated the 2015 catches and supported current assumptions that the passive gear type, the low diversity of bycatch, and the rapid hand-sorting of the trap minimize the impact of the lobster fishery on incidentally captured taxa. Further scientific monitoring is recommended to better account for all sources of mortality in stock assessments and rebuilding plans.
  • OPEN ACCESS
    Community science to the rescue: capturing water quality data during the COVID-19 pandemic
    FACETS • Vol. 8 • pp. 1 - 12
    In 2020, the COVID-19 pandemic interrupted all aspects of human activity, including environmental research and monitoring. Despite a lack of laboratory access and other restrictive measures, we adapted an existing community science monitoring program to continue through the summer of 2020. We worked with local community groups to recruit 58 volunteers who collected lake water samples from 60 sites on 16 lakes in south-central Ontario from June to September 2020. We organized drop-off depots and had volunteers freeze samples to monitor nearshore nutrients (phosphorus and nitrogen) and chlorophyll-a. A survey was distributed to volunteers to analyze lake-front property owners’ activities during the pandemic. We found spatial patterns in nearshore water quality across the lakes, with sub-watershed development being a significant predictor of nutrients and chlorophyll-a. Additionally, pre-pandemic (2019) and pandemic (2020 and 2021) nutrient concentrations were compared, but there was no clear impact of the pandemic on nearshore nutrient concentrations, despite changes in lake-front property owners activities. Overall, this study demonstrated the ability of community science to provide water quality data on a large spatial scale despite a major societal disruption, providing insight into regional nutrient trends during the first year of the pandemic.
  • OPEN ACCESS
    Applying ensemble ecosystem model projections to future-proof marine conservation planning in the Northwest Atlantic Ocean
    FACETS • Vol. 8 • pp. 1 - 16
    Climate change is altering marine ecosystems across the globe and is projected to do so for centuries to come. Marine conservation agencies can use short- and long-term projections of species-specific or ecosystem-level climate responses to inform marine conservation planning. Yet, integration of climate change adaptation, mitigation, and resilience into marine conservation planning is limited. We analysed future trajectories of climate change impacts on total consumer biomass and six key physical and biogeochemical drivers across the Northwest Atlantic Ocean to evaluate the consequences for Marine Protected Areas (MPAs) and Other Effective area-based Conservation Measures (OECMs) in Atlantic Canada. We identified climate change hotspots and refugia, where the environmental drivers are projected to change most or remain close to their current state, respectively, by mid- and end-century. We used standardized outputs from the Fisheries and Marine Ecosystem Model Intercomparison Project and the 6th Coupled Model Intercomparison Project. Our analysis revealed that, currently, no existing marine conservation areas in Atlantic Canada overlap with identified climate refugia. Most (75%) established MPAs and more than one-third (39%) of the established OECMs lie within cumulative climate hotspots. Our results provide important long-term context for adaptation and future-proofing spatial marine conservation planning in Canada and the Northwest Atlantic region.
  • OPEN ACCESS
    A social–ecological geography of southern Canadian lakes
    FACETS • Vol. 8 • pp. 1 - 16
    Anthropogenic pressures, including urban and agricultural expansion, can negatively influence a lake's capacity to provide aquatic ecosystem services (ES). However, identifying lakes most at risk of losing their ES (i.e., higher vulnerability) requires integrating information on lake ecological state, global change threats, and ES use. Here, we provide a social–ecological framework that combines these features within a regional context by evaluating the ecological state of 659 lakes across Canada. Using the deviation of impacted lakes from reference ones, we identified much higher total nitrogen and chloride concentrations as the main indicators of an altered lake ecological state in all regions identified. Lake ecological state was mapped using an additive colour model along with regional scores of threat levels and recreational ES use. Urban and agriculturally developed areas were linked to higher lake vulnerability and ES loss. Lakes in Southern Ontario were most concerning, being highly altered, under threat, and heavily used. Lakes near coastal urban centers were altered and used, but less threatened, whereas those in the Prairies were altered and threatened, but less used. Our novel framework provides the first social–ecological geography of Canadian lakes, and is a promising tool to assess lake state and vulnerability at scales relevant for management.
  • OPEN ACCESS
    Impact of plastic pollution on atmospheric carbon dioxide
    FACETS • Vol. 8 • pp. 1 - 7
    Since the beginning of its large-scale production in the early 20th century, plastics have remained an important material in widespread use throughout modern society. Nevertheless, despite possessing many benefits, plastics are resistant to degradation and instead accumulate in the ocean and terrestrial sediments, thereby potentially affecting marine and terrestrial ecosystems. Plastics release CO2 throughout their entire lifecycle; during the extraction of materials used in their production, through plastic–carbon leaching in the marine and terrestrial environment, and during their different end-of-life scenarios, which include recycling, landfill, and incineration. Here, we use the University of Victoria earth system climate model to quantity the effects on atmospheric CO2 and the ocean carbon cycle by using upper-bound estimates of carbon emissions from marine plastic–carbon leaching or land-based incineration. Despite the suggestions of some, our results indicate that it has only a very minor influence and an insignificant effect on the earth's global climate system. This holds even if plastic contamination increases well beyond current levels. On the other hand, carbon emissions associated with plastic production and incineration have a greater impact on climate while still dwarfed by emissions associated with the combustion of fossil fuels (coal, oil, and natural gas) and other anthropogenic sources. Our results have important policy implications for ongoing United Nations Environment Programme Intergovernmental Negotiating Committee on Plastic Pollution negotiations.
  • OPEN ACCESS
    How do human actions affect fisheries? Differences in perceptions between fishers and scientists in the Maine lobster fishery
    FACETS • Vol. 7 • pp. 174 - 193
    The degree to which human actions affect marine fisheries has been a fundamental question shaping people’s relationship with the sea. Today, divergences in stakeholder views about the impacts of human activities such as fishing, climate change, pollution, and resource management can hinder effective co-management and adaptation. Here, we used surveys to construct mental models of the Maine lobster fishery, identifying divergent views held by two key stakeholder groups: lobster fishers and marine scientists. The two groups were differentiated by their perceptions of the relative impact of pollution, water temperature, and fishing. Notably, many fishers perceive the process of fishing to have a positive effect on fisheries through the input of bait. Scientists exhibited a statistically significantly stronger concern for climate change and identified CO2 as one of the dominant pollutants in the Gulf of Maine. However, fishers and scientists agreed that management has a positive impact, which appeared to be a change over the past two decades, possibly due to increased collaboration between the two groups. This work contributes to the goal of decreasing the distance between stakeholder perspectives in the context of a co-managed fishery as well as understanding broader perceptions of impacts of human activities on marine ecosystems.
  • OPEN ACCESS
    Uptake of PCBs into sediment dwellers and trophic transfer in relation to sediment conditions in the Salish Sea
    FACETS • Vol. 7 • pp. 936 - 965
    We examined uptake of polychlorinated biphenyls (PCBs) into various marine sediment feeders relative to physical and geochemical factors and transfer to higher trophic levels. PCBs exceeding Canadian Council Ministers of the Environment Guidelines by 6–55× were found in industrialized harbours and some near-outfall sediments, indicating ongoing land input. Sediment PCBs were correlated with organic flux and content. Tissue PCBs were >10× sediment PCBs in all samples and highest in Victoria Harbour infauna, suggesting considerable uptake from these extremely contaminated, organically enriched, chronically disturbed sediments. Sediment PCBs were the primary predictor of tissue lipid PCBs followed by %fines. This results in generally higher tissue PCBs in more depositional regions. The lipid/sediment PCBs (uptake rate) declined with increasing sediment PCBs, acid volatile sulfides and benthos biomass turnover. PCB homologue composition did not change with uptake from sediments or at higher trophic levels, suggesting minimal metabolization in tissues. Trophic bio-magnification occurs since lipid PCBs were 2–100× higher in seal blubber than sediment feeders. PCBs were compared with polybrominated diphenyl ethers (PBDEs) for the same samples. PCBs were highest in industrialized harbours, whereas PBDEs were elevated in harbours but highest near wastewater discharges. This reflects differences in usage history, sediment dynamics, and affinities. PCBs appear to be more bio-accumulative and persistent at higher trophic levels than PBDEs.
  • OPEN ACCESS
    A novel morphometry-based method for assessing maturity in male Tanner crab, Chionoecetes bairdi
    FACETS • Vol. 7 • pp. 1598 - 1616
    Accurate classification of maturity status and estimation of size at 50% maturity for male crabs are important to the management of North Pacific crab stocks, which form the basis of several economically valuable fisheries. We demonstrate a straightforward maturity classification approach applied to male Tanner crabs (Chionoecetes bairdi), based on the use of log-transformed chela height distributions calculated via kernel density functions. The linear equation defining the relationship between the minima of these chela height distributions, and the midpoint of the corresponding carapace width bins is then used to estimate the incidence of maturity by size group across the population. We demonstrate the performance of this approach relative to two other currently applied methodologies. Finally, we apply this method to assess annual size at 50% maturity in eastern Bering Sea male Tanner crabs, and spatiotemporal trends in this parameter. We demonstrate the existence of high interannual and spatial variability in this population metric and find evidence of a decline in size at maturity in the western stock.
  • OPEN ACCESS
    Learning from Indigenous knowledge holders on the state and future of wild Pacific salmon
    FACETS • Vol. 7 • pp. 718 - 740
    In response to colonial research paradigms that have subjugated Indigenous Peoples, knowledges, lands, and waters, Indigenous research methodologies have emerged to center Indigenous visions and voices in research practice. Here, we employ such methodologies to improve collective understanding of the state and future of wild Pacific salmon (Oncorhynchus spp.) and fish–people–place relationships across British Columbia’s three largest salmon-producing rivers: the Fraser, Skeena, and Nass. Through partnerships with 18 communities of “Salmon People” and semi-structured interviews with 48 knowledge holders (i.e., Elders), we learned that, on average, Elders spent more than half of a century actively engaged in salmon fishing and processing. Modern salmon catches are reported to be approximately one-sixth of what they were estimated to be five to seven decades ago, and the top five threats to salmon identified by Elders included (i) aquaculture, (ii) climate change, (iii) contaminants, (iv) industrial development, and (v) infectious diseases. Threat priorities varied regionally, reflecting distinct lived experiences and regional variation in the prevalence and impact of different threats. Elders perceived threats to salmon equally as threats to aquatic health and human well-being, with evidence that the relationships between people and water, and salmon and people, are being profoundly transformed.
  • OPEN ACCESS
    A climate-resilient marine conservation network for Canada
    FACETS • Vol. 7 • pp. 571 - 590
    Climate change and biodiversity loss are twin crises that are driving global marine conservation efforts. However, if unaccounted for, climate change can undermine the efficacy of such efforts. Despite this, integration of climate change adaptation and resilience into spatial marine conservation and management has been limited in Canada and elsewhere. With climate change impacts becoming increasingly severe, now is the time to anticipate and reduce impacts wherever possible. We provide five recommendations for an inclusive, proactive, climate-ready approach for Canada’s growing marine conservation network: (1) integrating climate-resilience as a universal objective of the Canadian Marine Conservation Network, creating and implementing (2) national transdisciplinary working groups with representation from all knowledge holders and (3) necessary tools that integrate climate change into conservation design, (4) defining operational and climate-relevant monitoring and management objectives, and (5) strengthening communication and increasing knowledge exchange around the roles and benefits of protected areas within government and towards the public. Canada’s extensive marine and coastal areas reflect national and international responsibility to engage on this issue. Canada is well positioned to assume a leading role in climate change adaptation for marine conservation and help accelerate progress towards international commitments around mitigating ongoing biodiversity loss and climate change.
  • OPEN ACCESS
    Which fish is this? Fishers know more than 100 fish species in megadiverse tropical rivers
    FACETS • Vol. 7 • pp. 988 - 1007
    Ethnobiological studies on folk, common, or popular names that fishers use to identify fish can help improve fisheries monitoring and collaborations between fishers and researchers. This study investigates fishers’ knowledge (recognition, naming, and habitat use) on 115 and 119 fish species, respectively, in the Negro and Tapajos Rivers, two megadiverse rivers in the Brazilian Amazon, and investigates the relationship between such knowledge and fish importance to fisheries, fish abundance, and fish size. We also compared fishers’ perceptions on fisheries and fish abundance with literature data on fish harvests and fish sampling. We interviewed 16 fishers in 16 communities (one fisher per community, 8 communities along each river). These fishers recognized an average of 91 ± 10.4 species in the Negro River and 115 ± 7.2 species in the Tapajos River, but all fishers recognized 114 species in Negro and all species in Tapajos. The fishers’ knowledge of fish species was positively related to fishers’ perceptions on fish abundance, size, and importance to fisheries in the Negro, but only positively related to fish size in the Tapajos. Our results highlight the usefulness of fishers’ knowledge to providing data on use and cultural relevance of fish species in high diversity aquatic ecosystems.