12 Works

Data from: Can we rely on selected genetic markers for population identification? evidence from coastal Atlantic cod

Per Erik Jorde, Ann-Elin Synnes, Sigurd Heiberg Espeland, Marte Sodeland & Halvor Knutsen
The use of genetic markers under putative selection in population studies carries the potential for erroneous identification of populations and misassignment of individuals to population of origin. Selected markers are nevertheless attractive, especially in marine organisms that are characterized by weak population structure at neutral loci. Highly fecund species may tolerate the cost of strong selective mortality during early life stages, potentially leading to a shift in offspring genotypes away from the parental proportions. In...

Data from: Stable coexistence of genetically divergent Atlantic cod ecotypes at multiple spatial scales

Halvor Knutsen, Per Erik Jorde, Jeffrey A. Hutchings, Jakob Hemmer-Hansen, Peter Grønkjær, Kris-Emil Mose Jørgensen, Carl Andre, Marte Sodeland, Jon Albretsen, Esben M. Olsen & Peter Grønkjaer
Coexistence in the same habitat of closely related yet genetically different populations is a phenomenon that challenges our understanding of local population structure and adaptation. Identifying the underlying mechanisms for such coexistence can yield new insight into adaptive evolution, diversification, and the potential for organisms to adapt and persist in response to a changing environment. Recent studies have documented cryptic, sympatric populations of Atlantic cod (Gadus morhua) in coastal areas. We analyzed genetic origin of...

Data from: Are we underestimating the occurrence of sympatric populations?

Per Erik Jorde, Anastasia Andersson, Nils Ryman & Linda Laikre
Sympatric populations are conspecific populations that co-exist spatially. They are of interest in evolutionary biology by representing the potential first steps of sympatric speciation and are important to identify and monitor in conservation management. Sympatric existence in freshwater habitats can be more easily defined than terrestrial ones, and a series of sympatric fish populations have been reported. Reviewing the literature pertaining to sympatric populations of salmonid fishes, we find that most cases of sympatry appear...

Data from: Personalities influence spatial responses to environmental fluctuations in wild fish

David Villegas‐Ríos, Denis Réale, Carla Freitas, Even Moland & Esben M. Olsen
1. Although growing evidence supports the idea that animal personality can explain plasticity in response to changes in the social environment, it remains to be tested whether it can explain spatial responses of individuals in the face of natural environmental fluctuations. This is a major challenge in ecology and evolution as spatial dynamics link individual- and population-level processes. 2. In this study we investigated the potential of individual personalities to predict differences in fish behaviour...

Data from: Seasonal dynamics of spatial distribution and overlap between Northeast Arctic cod (Gadus morhua) and capelin (Mallotus villosus) in the Barents Sea

Johanna Fall, Lorenzo Ciannelli, Georg Skaret & Edda Johannesen
The trophic link between cod (Gadus sp.) and capelin (Mallotus sp.) is important in many panarctic ecosystems. Since the early 2000s, the Northeast Arctic cod stock (G. morhua) in the Barents Sea has increased greatly, and the sea has been exceptionally warm. Such changes have potentially large effects on species distributions and overlap, which in turn could affect the strength of species interactions. Due to its high latitude location, the Barents Sea has strong seasonal...

Data from: Potential of a no-take marine reserve to protect home ranges of anadromous brown trout (Salmo trutta)

Susanna H. Thorbjørnsen, Even Moland, Colin Simpfendorfer, Michelle Heupel, Halvor Knutsen & Esben M. Olsen
1. The extent to which no‐take marine reserves can benefit anadromous species requires examination. 2. Here, we used acoustic telemetry to investigate the spatial behavior of anadromous brown trout (sea trout, Salmo trutta) in relation to a small marine reserve(~1.5 km2) located inside a fjord on the Norwegian Skagerrak coast. 3. On average, sea trout spent 42.3 % (±5.0% SE) of their time in the fjord within the reserve, a proportion similar to the area...

Data from: Fishing pressure impacts the abundance gradient of European lobsters across the borders of a newly established marine protected area

Portia Nillos-Kleiven, Sigurd Heiberg, Esben Olsen, Rene Abesamis, Even Moland & Alf Kleiven
Marine protected areas (MPAs) are considered as viable fisheries management tools due to their potential benefits of adult spillover and recruitment subsidy to nearby fisheries. However, before-after-control-impact (BACI) studies that explore the biological and fishery effects of MPAs to surrounding fisheries are scarce. We present results from a fine-scale spatial gradient study conducted before and after the implementation of a 5km2 lobster MPA in southern Norway. A significant non-linear response in lobster abundance, estimated as...

Data from: Food-web structure varies along environmental gradients in a high-latitude marine ecosystem

Susanne Kortsch, Raul Primicerio, Michaela Aschan, Sigrid Lind, Andrey V. Dolgov & Benjamin Planque
Large-scale patterns in species diversity and community composition are associated with environmental gradients, but the implications of these patterns for food-web structure are still unclear. Here, we investigated how spatial patterns in food-web structure are associated with environmental gradients in the Barents Sea, a highly productive shelf sea of the Arctic Ocean. We compared food webs from 25 subregions in the Barents Sea and examined spatial correlations among food-web metrics, and between metrics and spatial...

Data from: Fine-scale population differences in Atlantic cod reproductive success: a potential mechanism for ecological speciation in a marine fish

Nancy E. Roney, Rebekah A. Oomen, Halvor Knutsen, Esben M. Olsen & Jeffrey A. Hutchings
Successful resource-management and conservation outcomes ideally depend on matching the spatial scales of population demography, local adaptation, and threat mitigation. For marine fish with high dispersal capabilities, this remains a fundamental challenge. Based on daily parentage assignments of more than 4000 offspring, we document fine-scaled temporal differences in individual reproductive success for two spatially adjacent (<10km) populations of a broadcast-spawning marine fish. Distinguished by differences in genetics and life history, Atlantic cod (Gadus morhua) from...

Data from: Harvesting changes mating behavior in European lobster

Tonje K. Sørdalen, Kim T. Halvorsen, Hugo B. Harrison, Charlie D. Ellis, Leif Asbjørn Vøllestad, Halvor Knutsen, Even Moland & Esben M. Olsen
Removing individuals from a wild population can affect the availability of prospective mates and the outcome of competitive interactions, with subsequent effects on mating patterns and sexual selection. Consequently, the rate of harvest-induced evolution is predicted to be strongly dependent on the strength and dynamics of sexual selection yet, there is limited empirical knowledge on the interplay between selective harvesting and the mating systems of exploited species. In this study, we used genetic parentage assignment...

Data from: Timing is everything: fishing‐season placement may represent the most important angling‐induced evolutionary pressure on Atlantic salmon populations

Alison C. Harvey, Yongkai Tang, Vidar Wennevik, Øystein Skaala & Kevin A. Glover
Fisheries‐induced evolution can change the trajectory of wild fish populations by selectively targeting certain phenotypes. For important fish species like Atlantic salmon, this could have large implications for their conservation and management. Most salmon rivers are managed by specifying an angling season of predetermined length based on population demography, which is typically established from catch statistics. Given the circularity of using catch statistics to estimate demographic parameters, it may be difficult to quantify the selective...

Data from: Cleaner fish escape salmon farms and hybridize with local wrasse populations

Ellika Faust, Kim T Halvorsen, Per Andersen, Halvor Knutsen & André Carl
The genetic impact of farmed fish escaping aquaculture is a highly debated issue. However, non-target species, such as cleaner fish used to remove sea lice from farmed fish, are rarely considered. Here we report that wild corkwing wrasse (Symphodus melops), which are transported long distances to be used as cleaner fish in salmon farms, escape and hybridize with local populations. Recently, increasing numbers of corkwing wrasse have been reported in Flatanger in Norway, north of...

Registration Year

  • 2018

Resource Types

  • Dataset


  • Norwegian Institute of Marine Research
  • University of Agder
  • University of Oslo
  • University of Gothenburg
  • James Cook University
  • The Arctic University of Norway
  • Oregon State University
  • Knipovich Polar Research Institute of Marine Fisheries and Oceanography
  • Aarhus University
  • Dalhousie University