Tag: Population genetics

Peer-reviewed articles

Lack of population genetic structure of lumpfish along the Norwegian coast: A reappraisal based on EST-STRs analyses

Contact

Davíð Gíslason

Project Manager

davidg@matis.is

Lumpfish is now the single most important cleaner fish species to date and there is an extensive lumpfish translocation along the Norwegian coast. A reliable baseline information about the population genetics structure of lumpfish is a prerequisite for an optimal managing of the species to minimize possible genetic translocation and avoid possible hybridisation and introgression with local populations. The current study is a follow up of the study by Jónsdóttir et al. (2018) using expressed sequence tag-short tandem repeats (EST-STRs) markers. Samples (N = 291) were analyzed from six sample locations along the Norwegian coastline from south to north, with additional 18 samples of first-generation (from wild fish) reared fish from a fish farm outside Tromsø (North Norway). Present findings show a lack of population differentiation among lumpfish sampling population along the Norwegian coast using EST-STRs, which is in accordance with the findings of Jónsdóttir et al. (2018) where genomic STRs (g-STRs) were analyzed. Present findings indicate that should translocated lumpfish escape from salmon sea pens in Norway, this will probably have little impact on the genetic composition of the local lumpfish population.

Reports

Preliminary project for research on the genetic composition of Icelandic herring compared to other stocks in the Northeast Atlantic: Biological diversity and processing properties / A pilot study on the multidisciplinary approach for the genetic stock identification of herring in the Northeast Atlantic: Biodiversity, functional and chemical properties

Published:

01/10/2013

Authors:

Sigurlaug Skírnisdóttir, Guðbjörg Ólafsdóttir, Sarah Helyar, Christophe Pampoulie, Guðmundur J. Óskarsson, Ásbjörn Jónsson, Jan Arge Jacobsen, Aril Slotte, Hóraldur Joensen, Henrik Hauch Nielsen, Lísa Libungan, Sigurjón Arason, Sindri Sigurðsson, Sigríður Hjörleifsdóttir, Anna K. Daníelsdóttir

Supported by:

Fisheries Project Fund, AG ‐ Fisk, Faroese Fisheries Research Fund, Research Studies Fund, Student Innovation Fund

Contact

Guðbjörg Ólafsdóttir

Specialist

gudbjorg.olafsdottir@matis.is

Preliminary project for research on the genetic composition of Icelandic herring compared to other stocks in the Northeast Atlantic: Biological diversity and processing properties / A pilot study on the multidisciplinary approach for the genetic stock identification of herring in the Northeast Atlantic: Biodiversity, functional and chemical properties

The purpose of the project was to:

· Develop a genetic analysis set with 20-25 genetic markers to assess the genetic composition and stock structure of herring in the Northeast Atlantic

· Use genetic makeup, milling and other biological factors to differentiate strains

· Study the relationship between stock units and the processing properties of herring

Knowledge of herring stocks is of great importance for the sustainable utilization and management of herring fisheries. A key factor for sustainable fisheries management and quota allocation is to know what stock units are in the fishing areas and how large they are. In this project, approx. 4,500 samples collected from nine possible stock units in the Northeast Atlantic in the years 2008 - 2012 (off Iceland, Norway, the Faroe Islands and Scotland). This extensive and extensive sample collection will then be used in further research projects. The results of a genetic analysis with 24 genetic markers showed that local herring stocks in fjords in Norway were significantly different from all other stock units. However, no significant differences were found for the possible stem units. Other more sensitive methods, such as DNA monopoly analysis (SNPs), may be able to differentiate between the strains, but this research has already begun in a new follow-up project. The biological information collected in the project did not differentiate between possible stem units. Studies of the Icelandic summer spawning herring and the Norwegian-Icelandic spring spawning herring showed differences in body color, water and fat content as well as stage of puberty and weight. No results have been obtained from the mill analyzes, but they will be published in connection with a doctoral project at the University of Iceland.

The aim of the project was:

· To develop a genetic approach based on 20-25 microsatellite loci to study the genetic variation of herring stocks in the Northeast Atlantic Ocean

· To use genetic, biological and otolith characters as discriminating parameters for stock identification

· To analyze physicochemical characteristics of different herring stocks

Sustainable fisheries management and quota decisions made by authorities are based on knowledge on fish stock structures and their sizes. Herring is a highly migratory fish species, and therefore it is likely to show low genetic differences among stocks. The mixed stock herring fishery creates considerable problems for the industry and the management of the stocks. In this project more than 4,500 individuals were sampled from 9 putative herring stocks in the Northeast Atlantic Ocean during the years 2008 and 2012. The sampling accomplished in the project is extensive and valuable for future research projects. The results of the genetic study based on 24 microsatellite genetic loci showed that the local Norwegian fjord stocks were significantly different from all other putative stocks. The other Northeast Atlantic herring stock units were not found to be significantly different. Power analyzes performed during this study revealed that sampling scheme, protocols and genetic design were sufficient to detect any level of genetic differentiation around 0.001. Therefore, a more sensitive type of genetic markers are needed for the problem addressed, such as SNPs (single nucleotide polymorphism) and that work has already started. Biological parameters alone did not have enough discriminating power for stock identification. The Icelandic summer ‐ spawning herring (ISSH) and the Norwegian spring ‐ spawning herring (NSSH) differed mainly in color and water / fat content. The herring from the two stocks were also found to be different in relation to maturity and weight. The methodology of otolith microstructure analyzes and their results will be published later in a PhD thesis at University of Iceland.

Report closed until 01.02.2015

View report

Reports

Turbot - a new colonist from the sea / Sandhverfa - a new settler from the deep

Published:

01/06/2012

Authors:

Sigurlaug Skírnisdóttir, Kristinn Ólafsson, Arild Folkvord, Matthías Oddgeirsson, Sigurbjörg Hauksdóttir, Steinunn Magnúsdóttir, Sigríður Hjörleifsdóttir, Snorri Gunnarsson, Hans Høie, Julie Skadal, Agnar Steinarsson, Albert Imsland

Supported by:

Fisheries Project Fund

Contact

Sigurlaug Skírnisdóttir

Project Manager

sigurlaug.skirnisdottir@matis.is

Turbot - a new colonist from the sea / Sandhverfa - a new settler from the deep

The purpose of the project was threefold:

• To obtain information on the distribution, migration and population growth of a sand dune near Iceland.  

• To use the reading of oxygen and carbon isotopes in grinders to assess the ambient temperature and life history of a sand dune near Iceland.  

• To develop DNA genotypes and assess the genetic variability of sandeels in Iceland and compare them with sandeels in nearby oceans.  

In total, samples were collected from 70 sandeels caught in Icelandic waters. The majority of the samples were collected off the southwest coast (67%) and this coincides with the ambient temperature in these areas, which is suitable for a sand dune. Sand turbines were found in the southeast and off the northeast in the autumn when the annual sea temperature in these areas is highest. About 300 samples were taken from the grinders of 25 sand turbines, aged 3 to 19 years, and oxygen (O) and hydrocarbon isotopes were analyzed by mass spectrometry. Using this method, the ambient temperature of the sampled fish was calculated to be in the range of 3-15 ° C. A clear seasonal fluctuation in ambient temperature was observed in the majority of the mills, although individual variability in ambient temperature was also significant. Lower calculated ambient temperatures were found in samples from the northeast compared to samples from the southwest and southeast coasts. The structure of a sand eel in Icelandic waters was studied with 12 genetic markers and it was compared with a sand eel from the northeast Atlantic and the Adriatic Sea. Significant genetic differences were found between all pairs of samples on the Kattegat and the Adriatic Sea, on the one hand, and between Iceland and the Irish Sea, as well as southern Norway and the Irish Sea. This basic study therefore suggests that sand eels in Icelandic waters may have originated in southern Norway. The results of the SETTLEMENTS project indicate that the sand dunes off Iceland are establishing themselves as a special Icelandic stock and that a new settler has arrived from the depths.

The aim of the LANDNEMI project was threefold:

• To collect information about distribution, migration and population growth of turbot in Icelandic waters.

• Use stable oxygen and carbon isotope signals in turbot otoliths to extract information about environmental and life history of turbot in Icelandic waters.

• To develop DNA multiplex microsatellites and determine intra- and inter-population genetic diversity of turbot.

Samples from 70 turbot caught in Icelandic fishing grounds were collected, with majority of the fish caught of the southwest coast (67%) in line with higher sea temperatures in those areas. The turbot caught in other fishing grounds around Iceland (southeast and northeast) were caught during fall when the sea temperatures reach the annual high. Nearly 300 otolith samples were extracted from otoliths of 25 turbot, with age ranging from 3 to 19 years, and subject to mass spectrometry determination of stable oxygen and carbon isotopes. The results from mass spectrometry analysis were then used to calculate temperatures experienced during the life span of the sampled turbot, and were found to be in the range from 3 to 15 ° C. Clear seasonal patterns in experienced temperature were observed in the majority of the turbot otoliths, although the individual range in experienced temperature varied substantially. A lower experienced temperature was indicated from a fish caught off Norðausturhorn compared to those caught off Suðvesturhorn and Suðausturhorn. The stock structure of turbot was investigated with 12 microsatellite markers in North-East Atlantic Ocean and the Adriatic Sea. Hierarchical analysis identified three primary genetic groups; one from the Adriatic Sea, one from Kattegat, and the third composing of samples from Iceland, south Norway, the Irish Sea and the North Sea. The third group was further divided into two clusters; Iceland and south Norway, and the Irish Sea and the North Sea. This pilot study suggests that the turbot in Icelandic waters may originate from southern Norway. Overall the results from the LANDNEMI project indicate that turbot around Iceland is emerging as an Icelandic stock unit and that the species could be considered a new colonist from the sea.

Report closed until 01.12.2013

View report

Reports

Population genetics of the Icelandic Nephrops norvegius stock / Stofnerfðafræði leturhumars á Íslandsmiðum

Published:

01/06/2010

Authors:

Sigurlaug Skírnisdóttir, Sigurbjörg Hauksdóttir, Kristinn Ólafsson, Christophe Pampouli, Hrafnkell Eiríksson, Steinunn Á. Magnúsdóttir, Guðmundur H. Gunnarsson, Guðmundur Ó. Hreggviðsson, Sigríður Hjörleifsdóttir

Supported by:

The Icelandic Fisheries Research Fund, the Student Innovation Fund

Contact

Sigurlaug Skírnisdóttir

Project Manager

sigurlaug.skirnisdottir@matis.is

Population genetics of the Icelandic Nephrops norvegius stock / Stofnerfðafræði leturhumars á Íslandsmiðum

As the name of the project "Stock genetics of lobster in Icelandic waters" indicates, the aim of the project was to examine the type of lobster (Nephrops norvegicus) in Icelandic waters, but stock type research is an important factor for sustainable fisheries management. The main objectives of the project were to develop new genetic boundaries to assess genetic variability within and between geographically separated hunting areas in Iceland, to define the paternity of female egg masses from separate hunting areas in order to shed light on the reproductive process of lobster breeding and to stem genetic factors. Genetic analysis involves the use of so-called genetic markers, which are based on specific DNA sequences that are somehow detectable in the genome. Genetic markers based on repeated short sequences (2-6 bases) are most commonly used, which are known to vary between individuals of the same species. These areas therefore vary in length between individuals and make them suitable options. Genetic analysis is a very powerful technology that can be used for individual analysis in a group of organisms. This method is now increasingly used for parental analysis, to assess population structure, for research traceability and to accelerate targeted breeding. Usually 5-15 different genetic markers need to be used to differentiate individuals. A large part of the development work is therefore to find the best conditions for PCR reactions, where as many genetic markers as possible can be used in one reaction (multiplex) and simultaneous runs on a sequencer. Well-made genetic analysis kits that are easy and cheap to use and provide a lot of information and good diagnostic skills are very useful for a variety of uses. They are therefore valuable products and marketers, as both genetic analysis and services based on them can be sold. The project developed eight new genetic markers for lobsters and used them to analyze samples from separate geographical fishing areas around Iceland, while Scottish lobster samples were used as a group. In addition, four previously published genetic markers were used for the analyzes. The results of analyzes with these 12 genetic markers from geographically separated regions (together with the subgroup) did not show a significant genetic difference of lobster between the regions. The results of the project have been published in articles and student projects. The student thesis is entitled "Development of microsatellite multiplex systems for Nephrops norvegicus" and is by Sóleyja Valgeirsdóttir. One article has been approved for publication in the project, which describes eight new genetic markers. The title of the article is: "Isolation and characterization of eight new microsatellite loci in the Norway lobster, Nephrops norvegicus (Linnaeus, 1758)" (approved for publication in the journal Molecular Ecology Resources, Appendix 1). Another article has been submitted for publication in the ICES Journal of Marine Science under the title "A pilot genetic study revealed the absence of spatial genetic structure of the Norway lobster (Nephrops norvegicus) at fishing grounds in Icelandic waters" but it deals with the structure of lobster in Icelandic waters where lobsters from Scotland were kept as an outing group (Appendix 2).

The genetic structure of population and mating behavior of exploited marine species are important criteria for effective fisheries management. The distribution of Nephrops norvegicus, Norway lobster, in Icelandic waters is limited to the warmer sea of the south coast. The distribution of the Icelandic stock can be divided into ten geographical areas but the main aim of this project was to develop microsatellite markers to use for the genetics analysis and to analyze whether the lobsters in each area are a self-contained unit stock or not. The aim was furthermore to determine the paternity of egg masses from individual females, and thus elucidate the breeding structure in Icelandic waters. The final goal was to produce a plan for the conservation and management of genetic resources in the Icelandic Norway lobster stock taking into account possible natural population diversity. Microsatellites are short sequence repeats of 2-6 bases found in all prokaryotic and eukaryotic genomes analyzed to date. Microsatellites are variable, which means the number of repeats in a specific area of the DNA variants between the different members of a species. Consequently, the alleles of the microsatellites differ by the length. The different alleles and thus the different length of the microsatellites can be caused by insertion or deletion of one or more repeats during the DNA replication. These sequences are usually under a high degree of length variability and that makes them as powerful genetic markers. Therefore, microsatellites are suitable for population genetics, for family tracing in breeding programs, genetic monitoring, and kinship studies as well as tracing of origin. Usually, 5-15 microsatellites are enough to discriminate between individuals. A microsatellite multiplex system is the use of multiple, unique primer sets in a single PCR mixture to produce amplicons of varying sizes, specific to different DNA sequences. By targeting multiple loci at once, additional information may be gained from a single reaction. It is a great advantage that microsatellite markers can be run in multiplex assay systems. Larger numbers of samples and smaller DNA quantities can then be genotyped at once, saving time and money. This also minimizes the risk of handling errors. In this study we developed eight new microsatellite markers that were used to characterize the genetic diversity of Norway lobster, in and between isolated geographical areas in Icelandic waters, and an out-group sample from Scotland. In addition, four previously published microsatellite markers were used for the analysis. The microsatellites did not detect significant genetic differentiation among the location sampled, not even among Icelandic samples and the out-group collected in Scotland. The outcomes of the project are two papers and one student report. The report is titled "Development of microsatellite multiplex systems for Nephrops norvegicus" by Sóley Valgeirsdóttir. The first paper is titled; „Isolation and characterization of eight new microsatellite loci in the Norway lobster, Nephrops norvegicus (Linnaeus, 1758)“ where the eight new loci are described (Molecular Ecology Resources; Appendix 1; accepted for publication). The second paper is titled "A pilot genetic study revealed the absence of spatial genetic structure of the Norway lobster (Nephrops norvegicus) at fishing grounds in Icelandic waters" (ICES Journal of Marine Science; Appendix 2; submitted).

View report
EN
IS EN