A5011725744- Marine and fisheries research
- Fish Ecology and Management Studies
- Marine Bivalve and Aquaculture Studies
- Isotope Analysis in Ecology
- Fish Biology and Ecology Studies
- Aquaculture Nutrition and Growth
- Genetic diversity and population structure
- Identification and Quantification in Food
- Ichthyology and Marine Biology
- Physiological and biochemical adaptations
- Genetic and phenotypic traits in livestock
- Marine and coastal ecosystems
- Arctic and Antarctic ice dynamics
- Environmental DNA in Biodiversity Studies
- Oceanographic and Atmospheric Processes
- Indigenous Studies and Ecology
- Aquatic Ecosystems and Phytoplankton Dynamics
- Fish biology, ecology, and behavior
- Aquatic life and conservation
- Reproductive biology and impacts on aquatic species
- Aquatic Ecosystems and Biodiversity
- Coral and Marine Ecosystems Studies
- Marine and coastal plant biology
- Aquatic Invertebrate Ecology and Behavior
- Geology and Paleoclimatology Research
Aarhus University
2015-2025
Grønlands Naturinstitut
2013-2016
Danish Centre for Marine Research
2005
Abstract The study of hybrid zones is central to our understanding the genetic basis reproductive isolation and speciation, yet very little known about extent significance in marine fishes. We examined population structure cod transition area between North Sea Baltic employing nine microsatellite loci. Genetic differentiation sample rest increased along a transect proper, with large increase level occurring Western area. Our objective was determine whether this pattern caused purely by...
Abstract Field metabolic rate (FMR) is key to understanding individual and population-level responses environmental changes, but challenging measure in field conditions, particularly aquatic environments. Here we show that FMR can be estimated directly from the isotopic composition of carbon fish otoliths (δ 13 C oto ). We describe relationship between δ values oxygen consumption rate, report results laboratory experiments relating individual-level measurements rates Atlantic cod ( Gadus...
A number of evolutionary mechanisms have been suggested for generating low but significant genetic structuring among marine fish populations. We used nine microsatellite loci and recently developed methods in landscape genetics coalescence-based estimation historical gene flow effective population sizes to assess temporal spatial dynamics the structure European flounder (Platichthys flesus L.). collected 1062 flounders from 13 localities northeast Atlantic Baltic Seas found temporally stable...
Abstract DNA from archived otoliths was used to explore the temporal stability of genetic composition two cod populations, Moray Firth (North Sea) sampled in 1965 and 2002, Bornholm Basin (Baltic 1928 1997. We found no significant changes allele frequencies for population, while subtle but over time were detected population. Estimates effective population size ( N e ) generally exceeded 500 both populations when employing a number varieties method. However, confidence intervals very wide 's...
Abstract Population structure was previously believed to be very limited or absent in classical marine fishes, but recently, evidence of weakly differentiated local populations has been accumulating using noncoding microsatellite markers. However, the evolutionary significance such minute genetic differences remains unknown. Therefore, order elucidate relationship between markers and adaptive divergence among we combined cDNA microarray analysis European flounders ( Platichthys flesus ). We...
Otoliths are remarkable recorders that store visual and chemical information can be interpreted with regard to individual fish phenotype trajectory, life history events environment. However, the stored in otoliths must knowledge otolith is an integral part of sensory systems. This means environmental signals recorded will regulated by homeostatic apparatus – its physiology ultimately genetic make-up. Although this may complicate interpretation signals, it also opens up avenues for new...
Coexistence in the same habitat of closely related yet genetically different populations is a phenomenon that challenges our understanding local population structure and adaptation. Identifying underlying mechanisms for such coexistence can yield new insight into adaptive evolution, diversification potential organisms to adapt persist response changing environment. Recent studies have documented cryptic, sympatric Atlantic cod (Gadus morhua) coastal areas. We analysed genetic origin 6,483...
Abstract Parallel evolution and the extent to which it involves gene reuse have attracted much interest. Whereas has theoretically been predicted under circumstances is expected, empirical studies that directly compare systems showing high low parallelism are rare. Three‐spined stickleback ( Gasterosteus aculeatus ), where freshwater populations independently founded by ancestral marine populations, represent prime examples of phenotypic genomic parallelism, but cases exist low. Based on RAD...
Abstract Over the past 3 decades, N orth Sea A tlantic cod ( G adus morhua ) have exhibited variable length‐at‐age along with declines in spawning stock biomass and timing of maturity. Multiple factors affecting growth development fish acted on this economically important over same period including warming waters an intensive fishery. Here, we employ as a model population, exploring how physiologically relevant temperature metric (the growing degree‐day, GDD ; °C day) can be used to compare...
Fishing and climate change impact the demography of marine fishes, but it is generally ignored that many species are made up genetically distinct locally adapted populations may show idiosyncratic responses to environmental anthropogenic pressures. Here, we track 80 years Atlantic cod (Gadus morhua) population dynamics in West Greenland using DNA from archived otoliths combination with fish niche based modeling. We document how interacting effects high fishing pressure lead dramatic...
Current knowledge on the feeding ecology of Greenland shark (Somniosus microcephalus), a potential top predator in arctic marine ecosystems, is based small sample sizes as well narrow size ranges sharks. Therefore, size-related patterns remain poorly documented. Using stomach content data (N=88) and stable isotope values white muscle tissue (N=40), this study evaluates diet sharks ranging from 81 cm to 474 (total length). The importance prey categories ('Fish', 'Mammal', 'Squid',...
Knowledge of metabolic costs associated with maintenance, foraging, activity and growth under natural conditions is important for understanding fish behaviours the bioenergetic consequences a changing environment. Fish performance in wild within complex environment can be investigated by analysing individual-level field rate and, at present, stable carbon isotope tracer otoliths offers possibility to reconstruct rate. The isotopic composition linked oxygen consumption through oxidation...
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 467:47-59 (2012) - DOI: https://doi.org/10.3354/meps09945 Spatial variability of carbon (δ13C) and nitrogen (δ15N) stable isotope ratios in an Arctic marine food web Joan Holst Hansen1,*, Rasmus Berg Hedeholm2,3, Kaj Sünksen2, Jens Tang Christensen1, Peter Grønkjær1 1Marine Ecology, Department Bioscience,...
Stable isotope studies of long-term ecosystem change are often hampered by lack archived tissue samples. Here, we provide a reliable method for extracting the organic matrix from fish otoliths, demonstrate differences in values between soluble and insoluble fractions, trophic enrichment factors (ε). The analyses were performed on otoliths wild-caught adult Atlantic cod (Gadus morhua) 6-month diet-switch experiment with juvenile cod. Acid hydrolysis otolith powder followed ultrafiltration...
Abstract The occurrence of natal homing in marine fish remains a fundamental question ecology as its unequivocal demonstration requires tracking individuals from fertilization to reproduction. Here, we provide evidence long‐distance (>1000 km) over more than 60 years Atlantic cod ( Gadus morhua ), through genetic analysis archived samples marked and recaptured individuals. Using high differentiation single‐nucleotide polymorphism assay, demonstrate that the vast majority tagged West...
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 154:91-105 (1997) - doi:10.3354/meps154091 Ontogenetic and environmental effects on vertical distribution of cod larvae in Bornholm Basin, Baltic Sea Grønkjær P, Wieland K Cod eggs are neutrally buoyant at depths exceeding 55 m. When these hatch must enter upper photic portion water column locate capture...
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 438:185-194 (2011) - DOI: https://doi.org/10.3354/meps09301 Sandeel as a link between primary production and higher trophic levels on Faroe shelf Kirstin Eliasen1,2,*, Jákup Reinert1, Eilif Gaard1, Bogi Hansen1,2, Jan Arge Jacobsen1, Peter Grønkjær2, Jens Tang Christensen2 1Faroe Research Institute, 110...
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 461:197-209 (2012) - DOI: https://doi.org/10.3354/meps09871 Tissue-specific turnover rates and trophic enrichment of stable N C isotopes in juvenile Atlantic cod Gadus morhua fed three different diets Torben Ankjærø, Jens Tang Christensen, Peter Grønkjær* Department Bioscience, Ecology, Aarhus University,...
Horizon scanning is an increasingly common strategy to identify key research needs and frame future agendas in science. Here, we present the results of first such exercise for field sclerochronology, thereby providing overview persistent emergent questions that should be addressed by studies. Through online correspondence following 5th International Sclerochronology Conference 2019, participants submitted rated either knowledge gaps or promising applications sclerochronology. An initial list...
Abstract Coexistence of ecotypes, genetically divergent population units, is a widespread phenomenon, potentially affecting ecosystem functioning and local food web stability. In coastal Skagerrak, Atlantic cod ( Gadus morhua ) occur as two such coexisting ecotypes. We applied combination acoustic telemetry, genotyping, stable isotope analysis to 72 individuals investigate movement ecology niche putative “Fjord” oceanic “North Sea” ecotypes—thus named based on previous molecular studies....
Retention or dispersion of larvae from the spawning grounds has been identified as one key processes influencing recruitment success in fish stocks.To examine potential effects transport on recruitment, numerical simulations were performed utilizing a three-dimensional physical oceanographic model Baltic Sea.Cod represented Lagrangian drifters released deepwater region Bornholm Basin, main ground for cod.Simulations major seasons 1993 and 1994, when annual interannual variability...