David Cote

Fisheries and Oceans Canada | DFO · Ecological Sciences

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 (Lo...

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...

In many rivers, natural variations in water discharge are affected by flow regulation related to hydropower production. Due to increased energy demand, there has been increased development of mini hydropower stations on small, steep rivers. As the majority of previous research has focused on experimental streams or larger river systems, knowledge o...

Previous studies have suggested that diets of river otters (Lontra canadensis) vary in response to seasonal shifts in prey availability, and that they select slowly moving fish of moderate size. To test these assumptions for marine-coastal river otters in Newfoundland, Canada, we reconstructed diets and estimated body length of important fish prey...

We examined the spatial dynamics of Atlantic cod, Gadus morhua, through its life history on the northeast and southeast coasts of Newfoundland in order to delineate dispersal and critical habitat requirements as potential determinants of appropriate spatial scales for management. Hydroacoustic surveys across the northeast Newfoundland shelf in 1990...

There has been considerable focus on winter studies of Atlantic salmon Salmo salar parr during the last two decades. However, a lack of knowledge exists about the linkage between the physical conditions, including ice, and parr behavior in flow environments during the cold season. In this study, the movement and growth of Atlantic salmon parr were...

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 density, biomass and estimated production of brook trout Salvelinus fontinalis and Atlantic salmon Salmo salar were related to habitat factors in streams of Terra Nova National Park, Newfoundland, Canada. Fish communities at 29 sites (18 brooks; 15 watersheds) were sampled in the summer of 2002, 2003 and 2005. Salmonid density, biomass per unit...

Though there has been an increased focus on the interaction between the physical habitat and the behaviour of Atlantic salmon parr (JAS; Salmo salar L.), only a few studies have attempted to link winter conditions using hydraulic variables and ice conditions with behaviour and habitat use in natural flow environments. In this study, mobility of Atl...

The fauna of insular Newfoundland compared to the mainland is depauperate, e.g., 35 spp of mayflies versus about 160 spp in Maine. The question is can this depauperate fauna provide good biomonitoring information? A comparative study using present /absent data from 85 sites in eastern Newfoundland was analyzed with particular reference to the Ephem...

Terra Nova National Park (TNNP) protects representative examples of the Central and Northshore Forest ecoregions of Newfoundland and includes over 206 bodies of water (Table A). These standing waterbodies make up 6% of the park’s area and are used for drinking water, are a focus of recreational activities and support wildlife including harvested po...

Restoration action was taken on three culverts situated on small high gradient streams in Terra Nova National Park with the objectives of reestablishing natural fish movements and naturalizing stream habitat. Old corrugated pipe culverts, which had excessive water velocities and were “perched” at the outflow, were replaced with oversized pipe culve...

The Northwest River is a beautiful rugged river, popular with kayakers and anglers. It flows over 60 kilometres from its headwaters in the Bay du Nord Wilderness Area, through open barren country and cascading falls before emptying into the Atlantic Ocean in Terra Nova National Park on the northeast coast of Newfoundland. For generations, local com...

Acoustic telemetry was used to monitor the movements and landscape scale habitat use of age 2–3 year juvenile Atlantic cod Gadus morhua in Newman Sound, a coastal fjord of Newfoundland, during late autumn and early winter (24 October 1999 to 22 January 2000). Substratum, bathymetric relief and depth use were studied to determine if it differed from...

A location-finding acoustic telemetry system (resolution +/-1 m) was used to map ocean substrates and to continuously monitor the habitat associations (substrate, water temperature, and depth) of 58 Age 2 to 3 juvenile Atlantic cod Gadus morhua from 11 August to 20 December 1999. Substrate use was studied in 2 stages to determine if it differed fro...

We monitored swimming speed of 2–3 year-old juvenile Atlantic cod (Gadus morhua) from August to December 1999, using a 2-D location finding acoustic telemetry system in a coastal area of Newfoundland, Canada. We concurrently monitored the locations of 22–41 individuals by triangulation using a fixed hydrophone array. We estimated average swimming s...

Scuba surveys were used to examine the seasonal abundance and habitat use (substrate, temperature, and depth) of two species of juvenile cod Gadus spp. over the diel cycle in a coastal area of Bonavista Bay, Newfoundland. The abundance of age-0 cod increased throughout the study period (from early August until mid-November), while that of age-1 and...

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A discussion of management options to restore the Atlantic salmon population in Northwest River, Terra Nova National Park, Newfoundland, Canada.

Short-term and long-term effects of intraperitoneal implantation of dummy acoustic transmitters (1.9-4.6% of the fishes' body weight) in wild juvenile Atlantic cod Gadus morhua were investigated. Short-term effects were examined by comparing critical swimming speeds 24 h after surgery for implanted, sham-implanted, and control groups using a Blazka...

Biological telemetry is a powerful technique that provides continuous and simultaneous monitoring of fish in their natural environment, in both space and time, enabling researchers to study fish without constraints associated with many study techniques in use today. This paper describes a new acoustic telemetry technology which relies on an advance...

This paper describes a pilot study investigating the effectiveness of a combined acoustic and radio transmitting (CART) tag employing a dynamic conductivity switch in monitoring the migratory behavior of adult Atlantic Salmon (Salmo salar) through an estuary environment. The unique feature of the transmitter is its ability to sense the electrical c...

A combined acoustic and radio transmitting (CART) tag employing a dynamic conductivity switch suitable for investigating the migratory behavior of diadromous fish is described. The unique feature of the transmitter is its ability to sense the electrical conductivity of the ambient water and therefore operate in the appropriate signal mode. Under fr...