David Cote

Fisheries and Oceans Canada | DFO · Ecological Sciences

The mesopelagic zone represents one of the few habitats that remains relatively untouched from anthropogenic activities. Among the many species inhabiting the north Atlantic mesopelagic zone, glacier lanternfish (Benthosema glaciale) is the most abundant and widely distributed. This species has been regarded as a potential target for a dedicated fi...

Ocean warming and Arctic sea ice decline are expected to affect biological pump efficiency by altering the timing, quantity, quality, and composition of export production. However, the origins and composition of sinking organic matter are still understudied for the oceans generally, and in ice-covered areas especially. Here we use compound-specific...

Benthic species assemblages are groups of species that co-occur on the seafloor. Linking assemblages to physical environmental features allows for understanding and predicting their spatial distribution. Species identity and abundance are commonly quantified using a taxonomic approach to assess benthic diversity, yet functional traits that describe...

The Government of Canada has committed to protect 10% of coastal and marine areas by 2020, which requires the creation of new protected areas throughout Canada’s marine territory. The Labrador Inuit Land Claims Agreement (LILCA), signed in 2005, established the Labrador Inuit Settlement Area (LISA) which includes 72,520 km2 of lands and 48,690 km2...

The polar cod, Boreogadus saida, is an abundant and ubiquitous forage fish and a crucial link in Arctic marine trophic dynamics. Our objective was to unravel layers of genomic structure in B. saida from Canadian waters, specifically screening for potential hybridization with the Arctic cod, Arctogadus glacialis, large chromosomal inversions, and se...

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...

The Gilbert Bay marine protected area (MPA) was established in Labrador, Canada to protect a resident population of Atlantic cod (Gadus morhua) and associated habitat. However, fisheries removals outside MPA boundaries have contributed to population decline and increases in potentially competing species may hinder recovery. Using acoustic telemetry...

A new species of holothuroid, Pseudothyone labradorensissp. nov. (order Dendrochirotida and family Sclerodactylidae), was discovered off the coast of Labrador (eastern Canada) at a depth of 740–969 m. Two specimens were described based on morphological and genetic parameters. Distinctive characters included pinkish body colour, presence of tube fee...

Unprecedented warm river temperatures in July 2023 in Labrador, a subarctic region of Canada, were the highest since monitoring began (1994–2023) and ranged from 19.4°C (Hunt River) to 22.5°C (Eagle River). Incipient lethal water temperatures were exceeded for adult Atlantic salmon and brook trout (≥25°C) on 14 days in five of seven rivers and Arct...

Species extinction and population extirpation are now widespread across aquatic ecosystems with many diadromous species, including Atlantic salmon (Salmo salar), in decline throughout much of the North Atlantic. Declines can occur simultaneously at both large and small regional scales rendering factors driving the decreases more elusive. On the sou...

Movements reflect important activities and life history events for animals, and therefore understanding what influences movement in organisms is increasingly important as climate change alters environmental conditions at unprecedented rates. This has relevance for predicting the effects of climate change on fitness and interpreting stock status of...

Predicting and measuring changes resulting from marine protected areas (MPAs) has posed a challenge for practitioners, partly because ecosystems are complex and can change in unanticipated ways, but also due to MPA characteristics such as design factors, conservation objectives (COs), and monitoring programs, that can leave little chance of meeting...

Predicting and measuring changes resulting from marine protected areas (MPAs) has posed a challenge for practitioners, partly because ecosystems are complex and can change in unanticipated ways, but also due to MPA characteristics such as design factors, conservation objectives (COs), and monitoring programs, that can leave little chance of meeting...

This popular literature article provides a general overview of the key decision points to optimize the application of eDNA.

The performance of environmental DNA (eDNA) metabarcoding has rarely been evaluated against conventional sampling methods in deep ocean mesopelagic environments. We assessed the biodiversity patterns generated with eDNA and two co-located conventional methods, oblique midwater trawls and vertical multinets, to compare regional and sample-level dive...

Resource user compliance is a key element in effective fisheries management. Herein, we examine two decades of enforcement records pertaining to Atlantic salmon from Newfoundland and Labrador, Canada. Illegal incidents were negatively correlated with the number of licensed anglers but not salmon abundance. Over two decades, illegal incidents declin...

The oceanography of the Labrador Sea is well studied because of its globally important deep‐water convection that oxygenates the deep ocean and drives climate‐regulating ocean currents. However, little is known about the fish communities that inhabit this area, particularly beyond the depths accessible to standard research surveys and commercial fi...

Accumulating evidence has demonstrated a decrease in post-release survival of angled Atlantic salmon (Salmo salar) during periods of warm water temperatures. Consequently, the application of water temperature-related fishery closures by resource managers is gaining interest. Here, the role of water temperature-related fishery closures in recreation...

FIPEX v10.4 is designed to decrease the time required to assess the individual and cumulative effects of river barriers to fish passage and to assess river connectivity from headwaters to outflow (i.e., longitudinal connectivity) Loss of longitudinal connectivity due to anthropogenic barriers is a global problem contributing to unprecedented biodiv...

Ongoing effects of climate change create a dual challenge of shifting distributions of organisms and concerns about the fate of organic carbon in nature. Marine sediments store vast amounts of organic carbon, but the fate of that material hinges on the biology of organisms associated with the seafloor and how they influence rates of carbon decompos...

Labrador Inuit have expressed concern about the impacts of climate change on their health and well-being and their future access to marine resources, including fisheries. This study filled important knowledge gaps identified by the Nunatsiavut Government and Inuit communities regarding benthic biodiversity and habitat structure within major geomorp...

We defined mesozooplankton biogeography in the North American Arctic to elucidate drivers of biodiversity, community structure, and biomass of this key component of the Arctic marine ecosystem. A multivariate analysis identified four mesozooplankton assemblages: Arctic-oceanic, Arctic-shelf, Coastal-Hudson, and Labrador Sea. Bathymetry was a major...

Across temperate and equatorial oceans, a diverse community of fish and zooplankton occupies the mesopelagic zone, where they are detectable as sound-scattering layers. At high latitudes, extreme day-night light cycles may limit the range of some species, while at lower latitudes communities are structured by dynamic ocean processes, such as temper...

Seafloor habitat maps are an important management tool used to delineate distinct regions of the seabed based on their biophysical properties. Spatially continuous bathymetry and backscatter-derived terrain features are commonly used as proxies for environmental conditions and processes that affect species distributions. Multi-scale approaches are...

This paper presents the first records of the brittle star Ophiactis abyssicola in Canadian waters and range extensions of up to 1900 km in the Northwest Atlantic from previously known locations. Samples were collected off northern Labrador and the northern portion of insular Newfoundland (eastern Canada) at 433 and 1097 m depths, respectively. This...

Climate change will alter ecosystems and impose hardships on marine resource users as fish assemblages redistribute to habitats that meet their physiological requirements. Marine gadids represent some of the most ecologically and socio-economically important species in the North Atlantic, but face an uncertain future in the wake of rising ocean tem...

We describe observations of sea lamprey (Petromyzon marinus) and striped bass (Morone saxatilis) incursions into Labrador, Canada. While P. marinus have been periodically observed in similar latitudes, their numbers have conspicuously increased in estuarine environments in 2020. In contrast, M. saxatilis were not observed from Labrador until 2017 b...

Arctic charr Salvelinus alpinus are a commercially and culturally valued species for northern Indigenous peoples. Climate shifts could have important implications for charr and those that rely on them, but studies that evaluate responses to ecosystem change and the spatial scales at which they occur are rare. We compare marine-phase habitat use, lo...

Numerous studies demonstrate the utility of information from coastal seine surveys for monitoring juveniles of Atlantic cod Gadus morhua , but few studies have linked such surveys to older ages within cohorts. We related juvenile (age-0 and -1) cod population components at a long-term monitoring site in Newfoundland to offshore pre-adult (age-3) co...

When faced with the loss of a population, resource managers often feel compelled to choose restoration strategies perceived to have low‐risk, such as the management of the ecological components of the system or the application of regulatory measures. It can be counterintuitive to share decision‐making and resource management with those who want to...

The oceans sequester 31% of atmospheric carbon annually 1, but the magnitude of biologically enhanced sequestration is not evenly distributed across the globe 2. Measuring surface primary productivity offers a reasonable proxy for estimating carbon flux into the ocean 3 but entirely misses the processes that affect carbon export to sequestration de...

Commercial Snow Crab (Chionoecetes opilio) harvesters believe marine noise from seismic surveys reduces commercial Snow Crab catch rates. Depending on the type of seismic survey used, animals living in a particular area could be exposed to loud noise (e.g. daily Sound Exposure Level (SEL) >165 dB re 1 μPa²·s) for periods ranging from hours (typical...

Warming water temperatures, combined with increased mortality following catch and release, could have synergistic consequences if rivers remain open to catch and release at high water temperatures, and catchability of fish remains similar across water temperatures. Here archived data for Atlantic salmon, Salmo salar L., were used to (a) quantify th...

The deep ocean is the largest biome on Earth and faces increasing anthropogenic pressures from climate change and commercial fisheries. Our ability to sustainably manage this expansive habitat is impeded by our poor understanding of its inhabitants and by the difficulties in surveying and monitoring these areas. Environmental DNA (eDNA) metabarcodi...

Sound is an environmental feature that is used by a variety of marine taxa for feeding, reproduction, navigation and predator avoidance. Consequently, alterations to the soundscape have the potential to alter an individual’s behaviour, physiology and ultimately fitness. Furthermore, such responses have the potential to negatively influence commerci...

The deep ocean is the largest biome on Earth and faces increasing anthropogenic pressures from climate change and commercial fisheries. Our ability to sustainably manage this expansive habitat is impeded by our poor understanding of its inhabitants and by the difficulties in surveying and monitoring these areas. Environmental DNA (eDNA) metabarcodi...

The resiliency of populations and species to environmental change is dependent on the maintenance of genetic diversity, and as such quantifying diversity is central to combatting ongoing wide spread reductions in biodiversity. With the advent of next‐generation sequencing, several methods now exist for resolving fine‐scale population structure, but...

Despite the challenges winter poses to salmonids inhabiting temperate and northern environments, there are relatively few studies that evaluate the factors that influence activity and habitat use during this season, particularly for lake environments that are ice-covered. This study examines brook trout depth distribution and movement (activity and...

Foreword This series documents the scientific basis for the evaluation of aquatic resources and ecosystems in Canada. As such, it addresses the issues of the day in the time frames required and the documents it contains are not intended as definitive statements on the subjects addressed but rather as progress reports on ongoing investigations.

Like many deeper ocean species, the fine-scale movement ecology of snow crab is not well understood. We integrated fine-scale positioning telemetry with larger-scale position estimates from autonomous mobile surveys and harvester returns to evaluate movements of male and female snow crab (Chionoecetes opilio). Effects of life stage–sex, temperature...

In this study, a series of experimental releases of aquaculture fish were conducted to simulate escapes in a Canadian fjord (Fortune Bay, Newfoundland and Labrador) and investigate the hierarchical influence of fish size, season, and release location on dispersal patterns and residency time within the fjord. The behaviour of farmed salmon on the so...

The restoration of four partial stream barriers was evaluated in watersheds of Terra Nova National Park, Newfoundland, Canada from 2009 to 2011. Brook trout (n = 462) were tagged and tracked moving through our study sites using PIT telemetry and the restoration actions were assessed using three different measures: passage success rates; the range o...

Sound is used by a variety of marine taxa for feeding, reproduction, navigation and predator avoidance and therefore alterations to the soundscape from industrial noise have the potential to negatively affect an animal's fitness. Furthermore, responses to industrial noise would also have the potential to negatively influence commercial fishing inte...

Fish exhibit habitat-specific distributions in heterogeneous landscapes. Many sampling techniques are limited to specific seabed types and have limited utility in comparisons of fish abundance among multiple habitats. We measured the relative abundance and the composition of fish communities in four naturally occurring coastal marine seabed types (...

This paper examines the effect of lake characteristics on population density and how this variation affects growth, mortality and population size structure of brook trout, Salvelinus fontinalis. The study was conducted on 17 recreationally fished, reproductively isolated boreal forest lakes in Newfoundland, Canada from 1993 to 2000. A standardized...

Coastal seine surveys contain some of the only direct measures of age-0 abundance for Atlantic cod (Gadus morhua) and Pacific cod (Gadus macrocephalus), yet their utility in forecasting future year-class strength has not been evaluated among regions. We analyzed coastal time series from the Gulf of Alaska, Newfoundland, and Norway to test the hypot...

Environmental heterogeneity can combine with evolutionary responses to create very dynamic and often locally independent populations across a landscape. Such complexity creates difficulties for managers trying to conserve populations across large areas. This study develops, applies, and tests the use of stochastic life-history modeling and Monte Ca...

Aquaculture companies operating along the south coast of Newfoundland have requested permission to use farmed European-origin Atlantic salmon in their operations to increase their competitiveness. Canada’s National Code on Introductions and Transfers of Aquatic Organisms requires that a risk assessment be conducted in evaluating requests for import...

Many studies have identified the importance of local adaptation in Atlantic salmon (Salmo salar) and the strong genetic differences that exist between allopatric or parapatric resident and anadromous populations. However, as truly sympatric migratory phenotypes of Atlantic salmon have not been studied, it remains unclear whether distinct genotypes...

Recent advances in the ability to quantify longitudinal connectivity of riverine systems is enabling a better understanding of how connectivity affects fish assemblages. However, the role of connectivity relative to other factors, such as land use, in structuring biological assemblages is just emerging. We assessed the relevance of a structural con...

Anthropogenic barriers to fish passage, such as culverts and dams, are major factors impeding the persistence and recovery of aquatic species. Considerable work has focused on mitigating these impacts; however, activities associated with measuring and restoring connectivity of aquatic ecosystems often face challenges in determining the passability...

We explored the importance of environmental drivers in structuring benthic macroinvertebrate communities along a spatial hierarchy (local to landscape scale) in Low Arctic stream systems that were previously unstudied. Macroinvertebrate communities from 29 sites in Low Arctic areas of northern Labrador and Québec, Canada, were quantified by taxonom...

Monitoring programs using benthic macroinvertebrates are well-used and expanding to areas where communities are species-poor. The sensitivity of these depauperate communities to environmental conditions, however, is not well known. In this study, impoverished benthic invertebrate communities were compared from three climatically and geologically di...

The reference-condition approach evaluates the ecological impact at a site of interest through comparisons to unimpacted sites of otherwise similar conditions. Reference conditions should ideally represent natural spatial and temporal variation of unimpacted systems, including infrequent disturbance events. This study examined the year-to-year vari...

Understanding the intrinsic variability of habitat-specific faunal communities is important to species conservation and ecosystem management. Community variability is driven by many environmental factors, including density-dependent habitat selection. Extensions of MacCall's Basin Model of density dependent habitat selection indicate that variance...

The effects on benthic macroinvertebrate communities of simulated degradation of streams enabled evaluation of the effects of starting condition, type of degradation, and biota descriptor on the type 1 and type 2 error rates of bioassessment. Benthic macroinvertebrate communities from five reference streams in the Fraser River basin (British Columb...

Evaluation of the ecological status of river sites in Canada is supported by building models using the reference condition approach. However, geography, data scarcity and inter-operability constraints have frustrated attempts to monitor national-scale status and trends. This issue is particularly true in Atlantic Canada, where no ecological assessm...

Lake morphometry and water chemistry were analyzed as predictors of brook trout and total salmonid biomass (brook trout, Atlantic salmon and Arctic char) in water bodies of Newfoundland. Lake morphometric variables included surface area, depth, perimeter and catchment area while water chemistry variables included conductivity/TDS and total Phosphor...

Despite heightened levels of protection, impacts of river fragmentation are widespread in Canada's National Parks. Fragmentation associated with dams and culverts is a pervasive stressor that impacts Species at Risk and/or culturally important species such as Atlantic salmon and American eel. While this ecological problem is tractable and efforts a...

Habitat connectivity has one of the most significant effects on the persistence and/or recovery of aquatic species. The modification of stream barriers is a critical step towards the reconnection of movement corridors for fish species. One important aspect in the improvement of stream barriers is an understanding of how barriers affect the movement...

Barriers (culverts and dams) can impede fish passage and affect the overall habitat connectivity of rivers. However, a challenge lies in how to conceptualize and adequately measure passability at barriers. We hypothesize that estimates of barrier and watershed connectivity are dependent on assumptions about the nature of passability, and how it is...

Young fish often avoid deep water to reduce predation risk from larger fish. Less clear are explanations for the avoidance of shallows by large piscivorous fish however, one hypothesis suggests that this distribution reduces contact with depth-limited semi-aquatic mammal and bird piscivores. We determined prey size selection of the river otter (Lon...

Habitat connectivity is a central factor in shaping aquatic biological communities, but few tools exist to describe and quantify this attribute at a network scale in riverine systems. Here, we develop a new index to quantify longitudinal connectivity of river networks based on the expected probability of an organism being able to move freely betwee...

The effect of anchor-ice dams on the physical habitat and behavioural responses of Atlantic salmon Salmo salar parr in a small, steep stream was investigated. Anchor-ice dams formed periodically, leading to a dynamic winter environment as the study reach alternated between riffle and walk dominated habitat. Parr demonstrated large individual variat...