Clupea harengus Archives

Atlantic herring Clupea harengus feeding in the Norwegian Sea are assumed to consist of Norwegian spring spawners (NSSH), Icelandic summer spawners (ISSH) and North Sea autumn spawners (NSAH). Putative Norwegian autumn spawners (NASH), Faroese autumn (FASH) and spring (FSSH) spawners also feed in the area.

However, until there is a method to discriminate between populations in mixed samples, fishery and survey data from the Norwegian Sea will be solely attributed to the predominating NSSH, ultimately causing biased stock assessments.

Hence, we evaluated if a panel of 120 single nucleotide polymorphisms (SNPs) associated with spawning characteristics and salinity preferences would be an effective discrimination tool. The overall observed levels of genetic differentiation were high (FST = 0.57, p < 0.001, 95% CI: 0.51−0.62). Spawners from stocks under current management (NSSH, NSAH and ISSH) were well separated, but the putative populations were not. Discriminant analysis of principal component as well as Structure runs confirmed the differentiation observed with FST. When the SNP panels were tested on commercial fishery samples of NSSH east of Iceland, up to 16% were assigned to ISSH.

This implies that catch data are seriously biased and demonstrates the potential of SNP panels as a tool to solve the problem. However, work is needed to develop improved SNP panels that effectively separate the putative populations from the managed stocks. We recommend that such a tool should be established in regular sampling of fishery and surveys in the Norwegian Sea and accounted for in future stock assessments, advice and management.

Forverkefni til rannsókna á erfðasamsetningu íslensku síldarinnar samanborið við aðra stofna í Norðaustur Atlantshafi: Líffræðilegur fjölbreytileiki og vinnslueiginleikar / A pilot study on the multidisciplinary approach for the genetic stock identification of herring in the Northeast Atlantic: Biodiversity, functional and chemical properties

Höfundur færslu Eftir admin
Dagsetning færslu 01/10/2013

Útgefið:

01/10/2013

Höfundar:

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

Styrkt af:

Verkefnasjóður sjávarútvegsins, AG‐Fisk, Rannsóknarsjóður sjávarútvegsins í Færeyjum, Rannsóknarnámssjóður, Nýsköpunarsjóður námsmanna

Tengiliður

Guðbjörg Ólafsdóttir

Sérfræðingur

gudbjorg.olafsdottir@matis.is

Forverkefni til rannsókna á erfðasamsetningu íslensku síldarinnar samanborið við aðra stofna í Norðaustur Atlantshafi: Líffræðilegur fjölbreytileiki og vinnslueiginleikar / A pilot study on the multidisciplinary approach for the genetic stock identification of herring in the Northeast Atlantic: Biodiversity, functional and chemical properties

Tilgangur verkefnisins var að:

· þróa erfðagreiningarsett með 20‐25 erfðamörkum til að meta erfðasamsetningu og stofngerð síldar í Norðaustur Atlantshafi

· nota erfðasamsetningu, kvarnagreiningar og aðra líffræðilega þætti til aðgreiningar stofneininga

· rannsaka tengsl á milli stofneininga og vinnslueiginleika síldar

Þekking á síldarstofnum hefur mikla þýðingu fyrir sjálfbæra nýtingu og stjórnun síldveiða. Lykilatriði fyrir sjálfbæra fiskveiðistjórnun og úthlutun kvóta er að hafa vitneskju um hvaða stofneiningar eru á veiðisvæðunum og hversu stórar þær eru. Í þessu verkefni var u.þ.b. 4.500 sýnum safnað úr níu mögulegum stofneiningum í norðaustur Atlantshafi á árunum 2008 ‐ 2012 (við Ísland, Noreg, Færeyjar og Skotland). Þessi víðtæka og umfangsmikla sýnasöfnun mun síðan nýtast í framhalds‐rannsóknarverkefnum. Niðurstöður erfðagreininga með 24 erfðamörkum sýndu að staðbundnir síldarstofnar í fjörðum í Noregi voru marktækt frábrugðnir öllum öðrum stofneiningum. Hins vegar fannst ekki marktækur munur fyrir hinar mögulegu stofneiningarnar. Aðrar næmari aðferðir eins og DNA einkirnisgreiningar (SNPs) geta mögulega greint á milli stofneininganna en þær rannsóknir eru nú þegar hafnar í nýju framhalds‐ verkefni. Þær líffræðilegu upplýsingar sem safnað var í verkefninu greindu ekki á milli mögulegra stofneininga. Rannsóknir á íslensku sumargotssíldinni og norsk‐ íslensku vorgotssíldinni sýndu mun á holdlit, vatns‐ og fituinnihaldi sem og kynþroskastigi og þyngd. Ekki eru komnar niðurstöður úr kvarnagreiningunum en þær verða birtar í tengslum við doktorsverkefni við Háskóla Íslands.

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 analyses 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 analyses and their results will be published later in a PhD thesis at University of Iceland.

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Guðbjörg Ólafsdóttir

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