Gesche Winkler

Gesche Winkler
Université du Québec à Rimouski UQAR | uqar · Institut des Sciences de la Mer de Rimouski (ISMER)

Dr. rer. nat

About

78
Publications
11,655
Reads
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1,123
Citations
Citations since 2017
40 Research Items
569 Citations
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
Additional affiliations
July 2007 - present
Université du Québec à Rimouski UQAR
Position
  • professor-researcher
January 2006 - December 2006
Université de Lille
Position
  • PostDoc Position
September 2000 - December 2005
Laval University
Position
  • PostDoc Position

Publications

Publications (78)
Article
Full-text available
Detailed in situ vertical and temporal distribution of appendicularians, marine snow, fecal pellets, nano- and microplankton were recorded simultaneously with environmental data in the San Jorge Gulf, Argentinean Patagonia (45°–47°S). Data were taken at a fixed station over 36 h in February 2014 with an autonomous Video Plankton Recorder and a Flow...
Article
Knowledge on the larval ecology of winter‐spawning fish from the Estuary and Gulf of St. Lawrence (EGSL), Canada, remains scarce due to the seasonal ice cover that prevents ichthyoplankton sampling using conventional methods. Two winter‐spawning species, Atlantic halibut (Hippoglossus hippoglossus) and Greenland halibut (Reinhardtius hippoglossoide...
Article
Full-text available
Abstract Larval settlement and recruitment are crucial phases in the benthic‐pelagic life cycle of marine benthic invertebrates that controls population dynamic and habitat connectivity. Our study investigated potential triggers driving the settlement of bivalve larvae in a highly dynamic intertidal coarse sand habitat. The early recruitment rate o...
Article
Full-text available
Diel vertical migration (DVM) of krill was studied throughout 36 h at a fixed station (46.05°S, 66.19°W; 98-m depth) located in the center of the San Jorge Gulf, Southern Patagonia area, during February 2014. Using an echosounder system, combined with an autonomous Video Plankton Recorder (Auto-VPR) and Jacknet samplings, we describe the migration...
Article
The aim of this study was to quantify somatic growth and reproduction of Thysanoessa raschii in response to environmental conditions in the St. Lawrence Estuary and Gulf of St. Lawrence, Canada. We sampled between 2010 and 2016 from spring to late summer and incubated individuals. Fresh molts were collected daily and measured to calculate the growt...
Article
Full-text available
The aim of this study was to explore an emerging discipline addressing the impact of anthropogenic noise on larval stages of marine organisms. We assessed the influence of boat noise on the feeding behaviour of the pelagic larvae of winter flounder (Pseudopleuronectes americanus, Walbaum, 1792). The hypothesis was that boat noise influences the fee...
Article
Full-text available
Blue whale survival and fitness are highly contingent on successful food intake during an intense feeding season. Factors affecting time spent at the surface or at depth in a prey patch are likely to alter foraging effort, net energy gain, and fitness. We specifically examined the energetic consequences of a demonstrated reduction in dive duration...
Article
Full-text available
The goal of this study was to evaluate and compare the short-term performances and the physiological plasticity of two cryptic species Eurytemora carolleeae and Eurytemora affinis (North-Atlantic clade) by simulating rapid advection from freshwater to brackish water conditions and reciprocally. To do so, two reciprocal transplant experiments withou...
Article
Full-text available
Krill species play a pivotal role in energetic transfer from lower to upper trophic levels. However, functional feeding responses, which determine how food availability influences ingestion rates, are still not well defined for northern krill species. Here, we estimated and compared the functional feeding responses on natural communities of phytopl...
Article
The St. Lawrence estuary (SLE) supports important nursery habitats for many fish species, including the newly re-established population of striped bass (Morone saxatilis). The present study aims to describe pelagic (5 m isobaths) and littoral (<1.5 m-deep) nearshore habitats of the SLE and to document their use by fish larvae and age-0 juveniles, e...
Article
Secondary dispersal (= migration) of bivalves occurs after metamorphosis and is a key recruitment process that can radically change patterns of primary settlement. An example of secondary dispersal is active migration behavior of bivalve recruits such as in bysso-pelagic drift. We hypothesize that these active migrations represent an energy cost fo...
Article
Full-text available
Arctic biodiversity has long been poorly documented and is now facing rapid transformations due to ongoing climate change and other impacts, including shipping activities. These changes are placing marine coastal invertebrate communities at greater risk, especially in sensitive areas such as commercial ports. Preserving biodiversity is a significan...
Article
Species characterized by low dispersal capacities, such as mysids, usually show evidence of genetic differentiation. Many mysids are broadly distributed and often show eurythermal and euryhaline traits. This study aimed to describe intraspecific genetic structure and the phylogeography of Neomysis americana, a key species of estuarine food webs in...
Article
Krill, as forage species, play a pivotal role in marine food webs by linking lower to upper trophic levels. Despite their ecological relevance, processes affecting their physiological condition and their feeding selectivity remain not well known. Here, we hypothesize that significant spatial fluctuations of environmental conditions in a Subarctic r...
Article
Full-text available
After being extirpated from the St. Lawrence River in the 1960s, striped bass (Morone saxatilis) were reintroduced to the estuary in 2002 and by 2008, they were naturally reproducing. To document the habitat use and feeding ecology of this reintroduced population, we examined the gut contents of 333 larvae and juveniles. Samples were collected in f...
Article
Foraging efficiency (FE) is determined by the ratio of energy intake to energy expen- diture and represents a metric for estimating the capacity to store energy. Blue whales Bal- aenoptera musculus rely mostly on stored energy reserves for reproduction. They feed almost exclusively on krill, which vary in density and abundance both spatially and te...
Article
Full-text available
After being extirpated from the St. Lawrence Estuary (SLE), striped bass (Morone saxatilis) were reintroduced in 2002, and by 2008 they were naturally reproducing. The increase of this reintroduced population prompted the need to document its nursery habitats utilization, which contribute to species recruitment. We analysed mortality-dispersion rat...
Article
Full-text available
The goal of this study was to understand the zooplankton community composition and food web structure in San Jorge Gulf (45°–47°S, 65°30'W), a highly productive marine ecosystem in southern Argentina. A spatial grid of 14 stations was sampled in 2014. The sampled zooplankton community was composed of 30 taxa, with copepods accounting for 83% of the...
Preprint
Neomysis americana dominates the macrozooplankton of the St. Lawrence estuarine transition zone. Our aim was to determine how the growth and reproduction of N. americana may be controlled by environmental factors. The population was sampled fortnightly at Saint-Jean-Port-Joli from May to October 2013. A Bhattacharya cohort analysis was applied to t...
Article
Neomysis americana dominates the macrozooplankton of the St. Lawrence estuarine transition zone. Our aim was to determine how the growth and reproduction of N. americana may be controlled by environmental factors. The population was sampled fortnightly at Saint-Jean-Port-Joli from May to October 2013. A Bhattacharya cohort analysis was applied to t...
Article
Full-text available
The analysis of the abundance and distribution of the early life-history stages of the western Baltic spring-spawning herring population, spanning 23 yr, revealed that the abundance of yolk-sac larvae was strongly spatially structured and significantly more abundant during the optimal temperature window for viable hatch of herring larvae (9 C to 13...
Article
Full-text available
Different krill species have a pivotal position in many marine food webs by both preying upon several tro-phic levels and being forage species for consumers. Within these food webs, different krill species coexist, though it remains unclear what mechanisms allow for the coexistence, for instance, of northern krill species in subarctic environments....
Poster
Full-text available
Muchas especies zooplantónicas realizan migraciones verticales diurnas, concentrándose cerca de la superficie durante la noche y descendiendo a zonas más profundas al amanecer. En este trabajo se realizó una descripción del comportamiento migratorio vertical del ensamble de dos especies de krill Euphausia lucens y Euphausia vallentinii presentes en...
Article
The Nordic krill Meganyctiphanes norvegica and Arctic krill Thysanoessa raschii both dominate the krill community within the Estuary and Gulf of St. Lawrence system where they are central forage species for its pelagic ecosystem. We developed a species‐specific physiological individual based model that implements the critical physiological processe...
Poster
Full-text available
Esta investigación formó parte del proyecto multidisciplinario MARES (MArine ecosystem health of the San Jorge Gulf: Present status and RESilience capacity), enmarcado dentro de “Pampa Azul”. El objetivo del presente estudio fue investigar la composición, la distribución espacial en relación con los factores ambientales y las relaciones tróficas de...
Article
Two dominant krill species Meganyctiphanes norvegica (Sars, 1857) and Thysanoessa raschii (Sars, 1864) coexist in the subarctic waters of lower St. Lawrence Estuary, Canada. Both species perform diel vertical migrations representing often large displacements of ~100–150 m through several temperature regimes. We studied the impact of temperature, a...
Article
Full-text available
Copepods are the main natural food of many marine fish larvae. However, enriched rotifers are the most commonly used live prey in larval rearing. Impacts on the feeding behavior, growth, survival, and fatty acid (FA) composition of winter flounder larvae fed with copepods and rotifers were determined and compared to the FA composition of the two li...
Preprint
Full-text available
Arctic biodiversity has been for a long time underestimated, situated in a region considered as an austere environment combined to the lack of knowledge. The analysis of environmental DNA (eDNA), a new method tracing DNA from macro-organisms, is changing the way we monitor aquatic biodiversity and has the potential to answer large-scale fundamental...
Preprint
Full-text available
Arctic biodiversity has been for a long time underestimated, situated in a region considered as an austere environment combined to the lack of knowledge. The analysis of environmental DNA (eDNA), a new method tracing DNA from macro-organisms, is changing the way we monitor aquatic biodiversity and has the potential to answer large-scale fundamental...
Article
Rivers’ damming disrupts the seasonal cycle of freshwater and nutrient inputs into the marine system, which can lead to changes in coastal plankton dynamics. Here we use a 3-D 5-km resolution coupled biophysical model and downscale it to a 400-m resolution to simulate the effect of damming the Romaine River in Québec, Canada, which discharges on av...
Poster
Spatio-temporal variations of the physiological condition and the feeding behaviour of Meganyctiphanes norvegica in the gulf of St. Lawrence
Presentation
Full-text available
In subarctic ecosystems, the krill communities are composed of many species, ranging from temperate to arctic, with diverse morphology and ecology. These krill species may express differential eco-physiological traits, which in turn may vary with strong seasonal changes in temperature and food supply in these environments. To enhance our capacity t...
Article
Full-text available
Ballast water is a major vector of non-indigenous species introductions world-wide. Our understanding of population dynamics of organisms entrained in ballast is largely limited to studies of zooplankton and phytoplankton. Bacteria are more numerous and diverse than zooplankton or phytoplankton, yet remain comparatively understudied. We apply a met...
Article
Arctic coastal ecosystems are likely to be strongly affected by predicted environmental changes such as sea-ice decline and increase in freshwater input and turbidity. These changes are expected to impact primary production dynamics and consequently benthic consumers. The trophic relationship between primary producers and benthic primary consumers...
Article
Full-text available
Le copepode calanoide Eurytemora affinis est un complexe d’especes cles des reseaux trophiques estuariens. En dominant les communautes planctoniques dans la plupart des estuaires de l’hemisphere nord, E. affinis permet un transfert d’energies vers les niveaux trophiques superieurs. Il influence directement le recrutement des especes de poissons et...
Presentation
Full-text available
Krill as forage species play a key role in energy transfer to higher trophic levels in marine ecosystems. In the St. Lawrence estuary, three krill species (Meganyctiphanes norvegica, Thysanoessa raschii, Thysanoessa inermis) coexist and dominate the macrozooplankton biomass. Although, these species are ecologically important, the dynamics of their...
Article
Full-text available
Our understanding of the systematics of the Eurytemora affinis complex developed at a fast pace over the last decades. Formerly considered as a complex of cryptic species, it is now believed to include three valid species: E. affinis, Eurytemora carolleeae, and Eurytemora caspica. American and European representatives have been studied in detail wi...
Poster
Full-text available
The St. Lawrence estuarine transition zone includes the interface between the freshwater and the brackish. The euryhaline and dominant copepod Eurytemora affinis occurs throughout the entire transition zone, but E. affinis is a sibling species complex with two morphologically similar but genetically distinct clades. The E. caroleeae and the North-A...
Poster
Full-text available
The lower St. Lawrence estuary (LSLE) is influenced by river discharge and saltwater inflow. Together with arctic water inflow and ice cover in winter, a strong stratification occurs resulting in a cold intermediate layer (CIL) from spring to autumn. This stratification provides thermal habitats. Here, we focus on two krill species Thysanoessa rasc...
Article
La campagne océanographique de deux semaines qui s'est déroulée à bord du navire de recherche le Coriolis II (photo ci­-dessous) dans la région du prospect Old Harry au coeur du golfe du Saint­Laurent s'est terminée le 21 juin dernier. Malgré une météo qui n'a pas toujours été favorable, plusieurs jours de forte mer et quelques nausées, cette campa...
Article
Full-text available
The cryptic species complex, Eurytemora affinis is an important component of the mesozooplankton of estuarine transition zones (ETZs). In the St Lawrence ETZ, two clades, the Atlantic and the North-Atlantic clades co-occur. However, their distribution along environmental gradients is spatially segregated, potentially because of differential habitat...
Article
Full-text available
Eurytemora affinis is the dominant copepod in the St Lawrence estuarine transition zone (ETZ). The distribution patterns of two co-occurring genetically divergent clades of E. affinis were analyzed. The Atlantic (A) and the North-Atlantic (NA) clade occurrences were spatially and temporally variable. Three and five distinctive habitats were found i...
Conference Paper
We review research demonstrating the importance of estuarine transition zones (ETZ) and associated turbidity maxima as nursery areas for young fish. More specifically in the St. Lawrence ETZ, the plankton food web is longitudinally organized across the frontal gradients. Elevated algae biomass occurs at the head of the ETZ, supporting a high zoopla...
Conference Paper
Full-text available
In Canada, interest in a potential new krill source focusses on the evaluation of biochemical composition of northern and arctic krill for nutraceutical, cosmetic and pharmaceutical industries. Our prime objective is to examine the ecological resilience of the krill stocks in the St. Lawrence system prior to human exploitation. Krill stocks must co...
Article
Full-text available
Stable isotope ratios of carbon (d13C) in zooplankton are widely applied in ecosystem-level studies of energy flux and trophic interactions. Carbonate (CaCO3) and lipid content are highly variable both among and within zooplankton species. Such variability can arise from the d13C-depleted nature of lipids as well as differences in carbon incorporat...
Article
Full-text available
The diet and feeding ecology of Eastern Canada–West Greenland bowhead whales were examined using fatty acid composition of the outer blubber layer of 50 individuals sampled during the summers of 2008 and 2009. Bowhead blubber was rich in the following fatty acids (FA): 14:0, 16:0, 16:1n–7, 18:0, 18:1n–11, 18:1n–9, 18:1n–7, 20:1n–11, 20:1n–9, 20:1n–...
Article
Full-text available
The Saguenay-St. Lawrence Marine Park (SSLMP) is a region that sustains a high abundance of zooplankton. The connectivity between zooplankton populations within the SSLMP and the surrounding areas was investigated for Calanus finmarchicus and C. hyperboreus. Deep-dwelling stage V copepodites (CVs) were collected in the Marine Park as well as in put...
Article
Full-text available
The objective of this study was to investigate the short-term impact of forest harvesting within the first year after perturbation on water quality and zooplankton in oligotrophic lakes of the eastern Canadian Boreal Shield. To achieve this objective a balanced multiple before/after-control-impact (MBACI) experimental design was used including four...
Article
Full-text available
The eastern Canada-West Greenland (EC-WG) bowhead whale Balaena mysticetus population is slowly recovering from the intensive commercial whaling of the 18th and 20th centuries. However, climate change, through effects on ice conditions and prey availability, is one of several threats that might affect bowhead whale recovery. In this study, we explo...
Article
Full-text available
This study aimed at describing changes in the stable isotopic composition of late copepodite stage V (CV) subarctic marine copepods (Calanus finmarchicus and C. hyperboreus) during overwintering non-feeding periods. Diapausing stage CVs sampled in deep waters of the Lower St. Lawrence Estuary (Québec, Canada) in late-September 2009 were monitored f...
Article
Full-text available
A literature review and a search through public databases revealed that little attention had been paid to the winter oceanographic conditions of the Saguenay Fjord. This observation led to an exploratory survey carried out in the Saguenay Fjord during winter 2010, providing the first historical winter measurements throughout the entire water column...
Article
Full-text available
This study defined the status quo of biogeographic domains and examined spatial patterns of stable isotopes (SIs) of carbon and nitrogen in relation to biophysical groupings to gain greater insight into how mesozooplankton may respond to continuous environmental change in the Canadian Arctic and sub-Arctic regions. Mesozooplankton communities were...
Article
Full-text available
Evolutionary diversification of the broadly distributed copepod sibling species complex Eurytemora affinis has been documented in the northern hemisphere. However, the fine scale geographic distribution, levels of genetic subdivision, evolutionary, and demographic histories of European populations have been less explored. To gain information on gen...
Article
This paper presents a hydrodynamic study of the St. Lawrence Estuary's estuarine transition zone, a 100 km region where fresh water from the river mixes with salt water from the estuary. The circulation of the estuarine transition zone is driven by strong tides, a large river flow, and well‐defined salinity gradients. For this study, a three‐dimens...
Article
Full-text available
While the populations of the copepod Eurytemora affinis are often morphologically (i.e. taxonomy) indistinguishable, the species complex is composed of genetically distinct clades, representing divergent evolutionary histories. The most distant clades, genetically and morphologically (i.e. phylogeny), are transatlantic clades: North American and Eu...
Article
The brackish water copepod Eurytemora affinis is the most abundant copepod species in the low salinity zone (2-15) of the Seine estuary. Despite its ecological importance, little is known about its population dynamics in the Seine. We studied the effects of temperature (10 °C and 15 °C) and salinity (5, 15 and 25) on reproduction under non-limiting...
Article
Full-text available
Invasive species are often composed of highly differentiated populations or sibling species distributed across their native ranges. This study analysed patterns of distribution and the evolutionary and demographic histories of populations within the native range of the copepod species complex Eurytemora affinis. Genetic structure was analysed for s...