Øystein Skaala

Research Activities

Laboratory:

Institute of Marine research, Department of Aquaculture.

Contact person (name and e-mail):

Øystein Skaala, oystein.skaala@imr.no.

Persons working on brown trout population genetics:

Øystein Skaala, Tove Karlsen, Kevin Glover, Kjartan Hovgård (University of Bergen).

General research topics of the laboratory:

Conservation and management, genetic population structure, phylogeography.

General description of research on brown trout population genetics:

After finishing studies on a fine-spotted brown trout population in the Hardangervidda mountain plateau the research is now focussed on genetic population structure of freshwater resident trout in the Hardangervidda mountain plateau and genetic effects of hatchery releases. Also, we study the genetic population structure of anadromous trout or seatrout in the two major Norwegian fjord systems, the Hardangerfjord and the Sognefjord. Finally we collaborate with Russian colleagues in a study on colonization routes of seatrout in Norway and the White Sea, Russia. We find that in many respects the brown trout is also an excellent model species for studies on some of the problems seen in connection with salmon farming.

Protein electrophoresis is the major molecular tool employed.

List of projects (brown trout) for the past 3 years:

Study #1

Researcher:	Øystein Skaala
Collaborators:	Geir Solberg (Syrtveit fiskeanlegg)
Source of project funding:	In house
Topic:	Gene diversity, natural hybridisation.
Objective:	Test hypotheses about hybrid origin of a «marmorated» salmonid population in River Otra.
Design:	Sections in the river were sampled by gillnetting, and individual trout assigned to «marmorated», «common» anh «intermediate» category and genotyped by protein electrophoresis. Observed alleles and genotypes were compared to those observed in brown trout, brook charr, Arctic charr, and salmon. Genotypic distributions in the various categories were compared.
Methodology:	Allozymes.
Trout population:	Resident and anadromous populations.
Origin of samples:	Norway, Atlantic Sea Basin.
Status:	Initiated in 1995, finished in 1996.

Study #2

Researcher:	Øystein Skaala
Collaborators:	Rolf Y. Jenssen (Statkraft Sima), Åsmund Tysse (Environmental division, Buskerud county).
Source of project funding:	Statkraft.
Topic:	Stocking effects and efficiency.
Objective:	To study effects of hatchery releases on wild stocks.
Design:	Stocked and nearby undisturbed lakes are sampled by gillnetting, and individual trout aged and assigned to origin (naturally spawned, hatchery stock 1 and 2) according to age and finclipping. Genetic variability in stocked and undisturbed populations is compared, and further compared to the variability in donor stocks. Furthermore, families of pure stocks and «hybridized» are individually tagged and performance compared through 1,5 year in hatchery and then after release in the wild to obtain further information about stock differences.
Methodology:	Allozymes, estimation of performance, i.e. survival, growth, maturation, feeding.
Trout population:	Hatchery stocks, resident populations.
Origin of samples:	Norway, Atlantic Sea Basin.
Status:	Initiated autumn 1996, continues to 2001.

Study #3

Researcher:	Kjartan Hovgård (MSc student), Øystein Skaala (superviser)
Collaborators:	Kevin Glover; Harald Sægrov (Rådgivende biologer)
Source of project funding:	In house
Topic:	Genetic diversity and gene flow.
Objective:	To study population structure and gene flow between Norwegian fjords.
Design:	Juvenile trout were sampled by electrofishing, aged, length- and weight recorded, and genotyped. Genetic variability in populations is compared.
Methodology:	Allozyme electrophoresis.
Trout population:	Anadromous populations.
Origin of samples:	Norway, Atlantic Sea Basin.
Status:	Samples collected, typing finished, study finished by end of 1998.

Study #4

Researcher:	Alexander Makhrov (Vavilov institute of General Genetics, Moscow, Russia), Øystein Skaala
Source of project funding:	In house.
Topic:	Genetic diversity, gene flow, isolation by distance.
Objective:	To study polyandry, intraspecific redd superimposition and assortative mating between native and introduced trout.
Design:	Samples are collected mainly by electrofishing, and genotyped by protein electrophoresis.
Methodology:	Allozymes.
Trout population:	Anadromous populations.
Origin of samples:	Russia, Norway, Atlantic Sea Basin and White Sea Basin.
Status:	Samples collected, most of typing finished, study to be continued.

Publications (brown trout genetics)

Journal papers:

Skaala, Ø. 1992. Genetic population structure of Norwegian brown trout. J.Fish Biol., 41, 631-646.

Skaala, Ø. & K.E. Jørstad. 1987. Fine-spotted brown trout (Salmo trutta): its phenotypic description and biochemical genetic variation. Can. J. Fish. Aquat. Sci., 44, 1775-1779.

Skaala, Ø. & K.E. Jørstad.1988. Inheritance of the fine-spotted pigmentation pattern of brown trout. Pol. Arch. Hydrobiol., 35, 295-304.

Skaala, Ø. & G. Solberg. 1997. Biochemical genetic variability and the taxonomic position of the marmorated trout in River Otra, Norway. Nord. J. Freshw. Res.

Skaala, Ø., K.E. Jørstad & R. Borgstrøm. 1991. Fine-spotted brown trout: genetic aspects and the need for conservation. J. Fish Biol., 39 (Supplement A), 123-130.

Skaala, Ø. K.E. Jørstad & R. Borgstrøm. 1996. Genetic impact on two wild brown trout (Salmo trutta) populations after release of non-indigenous hatchery spawners. Can. J. Fish. Aquat. Sci., 53, 2027-2035.

Technical Reports:

Skaala, Ø., K.E. Jørstad og R. Borgstrøm, 1992. Oppdrettsfisk og villfisk. Fiskets Gang, nr 1:26-30.

Skaala, Ø. Å. Tysse og R. Jenssen. 1997. Genetiske effekter av fiskeutsetting. Prosjektrapport, August 1997.

Theses (eg, PhD and MSc theses):

Skaala, Ø. 1992. Genetic variation in brown trout Salmo trutta L., and application of genetic markers in studies on gene flow from cultured populations. Dr. Scient. thesis. Institutt for fiskeri og marinbiologi, Universitetet i Bergen.