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




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


Sigurlaug Skírnisdóttir

Project Manager

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

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